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alamo5000
20 December 2015, 10:10
As we all know I am building my SBR but yesterday the conversation turned to building a load for that type of rifle.

There is a lot of talk about dwell time and all that when talking about shorter barrels (mine is 10.5 with a 1/7 twist)...

I have done some google fu and with a standard 55 grain bullet muzzle velocity will be around 2500 fps out of a 10.5 barrel.

In my 16" rifle I am getting around 2600 fps with 69 grain SMKs. So just doing the math here (in theory) that if I shot my current loads through a 10.5 barrel my muzzle velocity would be down to under 2000 fps.

That said wouldn't that increase dwell time? Really though that's not my question or point of discussion... I am assuming that all these loads would run flawlessly through the gun....

On the flip side if I go with a lighter projectile I get my velocity up substantially but there are obviously trade offs to doing this.

On the really light side you have 40 grain bullets... and on the heavy side you have 77 grain bullets...

Basically considering that I am talking 200 yards tops so the real long range benefits of a 77 grain is kind of negated as to ballistics. That said I am of the school that more lead the better.

Basically it would boil down to what would be equivalent to a light load with a 77 grain (or other heavy round) or a faster load with a lighter projectile.

I also have a little bit faster burning of a powder that I am going to experiment with (H4895)

After thinking it over it might be best to go somewhere in the middle...a 55 or 62 grain bullet...but I am not really sure.

What do you reloaders think?

The end result is to be able to have an accuratized and effective load that is built for my gun. Also mainly I can reload fast and cheap...to get that consistent load...

Any ideas???

Molon, Molon! Where are you at bro!!![:D]

DeviantLogic
20 December 2015, 15:59
Generally speaking, you pick the bullet weight off the barrel twist rate. The faster the twist rate, the heavier the bullet,

In an ideal world, you pick the barrel based on the bullet you will be shooting. There are formulas out there for matching up the barrel twist rate and bullet specifics...https://en.wikipedia.org/wiki/Miller_twist_rule. *Note that barrel length is not a determining factor.

Even with the "ideal" bullet weight/twist rate calculated, your barrel may still like different grain bullets more or less.

***Hopefully Molon will respond...I'm sure his explanation/recommendations will be better than mine!

DeviantLogic
20 December 2015, 16:24
Sorry, didn't see where you had posted the twist rate. Honestly I'd go with 77gr. For the best accuracy, perform a ladder test to determine the sweet spot for your specific combination of bullet, powder, and barrel.

alamo5000
20 December 2015, 17:46
If it's straight up on twist rate that's one thing... it cuts down the hunt quite a bit for a suitable projectile. Maybe I was just doing my regular bit of over thinking... on a regular rifle it pretty much all makes sense to me. With an SBR though I got to wondering about velocity and all that stuff too.

If I go with the 75 grains based on the hogdon reload data and a little bit of guesswork I would be right around 2000 fps. I just kind of wonder if that would matter...Of course I wouldn't want to get shot with it.

I punched all that into a ballistics calculator and it would seem alright for the purpose intended...especially considering it's a 1x optic.

I am having to kind of fight my nature to go for accuracy for long range and all that. Accuracy yes... but in this case out to 200 yards I am pretty sure I would be doing ok.

I just wonder if a low velocity 75 grain shot would be more destructive than a faster 55 grain...

alamo5000
20 December 2015, 17:54
I wonder what this video would look like with a 75 or 77 grain bullet....

(Watch below)

https://www.youtube.com/watch?v=6CYq3t0rC_I

voodoo_man
20 December 2015, 18:37
77gr otm works wonders.

3inch group at 100y in my 7.75 inch pws mk107 upper.

Its seriously an awesome round.

Does cool stuff to people too.

alamo5000
20 December 2015, 18:54
77gr otm works wonders.

3inch group at 100y in my 7.75 inch pws mk107 upper.

Its seriously an awesome round.

Does cool stuff to people too.

I will take your word for it when it comes to 'cool stuff to people' [:D] LOL!

Just knowing me if it can be made accurate it will be made accurate [BD] It's just one of the things I am better at doing. It takes a certain level of nerdiness to make it be right on zero. That said to be honest I am specifically NOT looking for dime size groups at 100 yards... it would be nice to do it but it's not the point behind the build.

That said for a gun that is designed like my SBR is designed bullet/round design matters but it has an entirely different aspect to it.

So far there have been several people saying go heavy. I was just kind of at a loss on what that would do considering the velocity loss (or exactly what kind of loss that would be)...

Molon
20 December 2015, 19:12
Are you loading just for accuracy, or are you also loading for terminal ballistic properties? Extensive testing done at Lake City decades ago determined that 60% of the cartridge accuracy was determined by the bullet.

So, if you are loading strictly for accuracy, the first thing you need to do is find a bullet that shoots well from your barrel.

EVERY BARREL IS A LAW UNTO ITSELF. (So say we all!)

What shoots well from my barrels, might not shoot well from your barrels. Also, twist rate only determines the gyroscopic stability factor of a bullet fired from a particular barrel. Twist rate will not determine what weight bullet will shoot the most accurately from your barrel. (Of course you must have enough twist to produce the minimum necessary amount of gyroscopic stability for a given bullet.)

I've owned several 1:7" twist barrels that shot slightly more accurately with 55 grain bullets than they did with 75-77 grain bullets. Since you stated that you would only be shooting to approximately to 200 yards you might not necessarily need the higher ballistic coefficient of the heaver/longer bullets, but that also doesn't mean that one of the heavier/longer bullets won't be the one to shoot the most accurately in your barrel, even at shorter distances.

One of the smallest 10-groups that I've fired from a semi-automatic AR-15 at a distance of 100 yards had an extreme spread of 0.428". The bullet used was the Barnes 85 grain Match Burner.



https://app.box.com/shared/static/82p8qofbagaech8qgnjcuek6bzb5365c.jpg



Another small 10-shot group fired from a semi-automatic AR-15 at a distance of 100 yards had an extreme spread of 0.474". The group was fired using Sierra 55 grain BlitzKings.


https://app.box.com/shared/static/uzajpcwtt0ie1v60zicazeuwp31c4ro0.jpg


Both of the groups pictured above were fired from barrels with 1:7.7" twists.


So find a bullet that your barrel likes, and then you can start making adjustments with different charges of different burning rate powders.

If you're loading for terminal ballistic properties, that's a whole nother ball game.

alamo5000
20 December 2015, 19:18
Are you loading just for accuracy, or are you also loading for terminal ballistic properties? Extensive testing done at Lake City decades ago determined that 60% of the cartridge accuracy was determined by the bullet.

So, if you are loading strictly for accuracy, the first thing you need to do is find a bullet that shoots well from your barrel.

EVERY BARREL IS A LAW UNTO ITSELF. (So say we all!)

What shoots well from my barrels, might not shoot well from your barrels. Also, twist rate only determines the gyroscopic stability factor of a bullet fired from a particular barrel. Twist rate will not determine what weight bullet will shoot the most accurately from your barrel. (Of course you must have enough twist to produce the minimum necessary amount of gyroscopic stability for a given bullet.)

I've owned severl 1:7" twist barrels that shot slightly more accurately with 55 grain bullets than they did with 75-77 grain bullets. Since you stated that you would only be shooting to approximately to 200 yards you might not necessarily need the higher ballistic coefficeint of the heaver/longer bullets, but that also doesn't mean that one of the heavier/longer bullets won't be the one to shoot the most accurately in your barrel, even at shorter distances.

One of the smallest 10-groups that I've fired from a semi-automatic AR-15 at a distance of 100 yards had an extreme spread of 0.428". The bullet used was the Berger 85 grain Match Burner.



https://app.box.com/shared/static/82p8qofbagaech8qgnjcuek6bzb5365c.jpg



Another small 10-shot group fired from a semi-automatic AR-15 at a distance of 100 yards had an extreme spread of 0.474". The group was fired using Sierra 55 grain BlitzKings.


https://app.box.com/shared/static/uzajpcwtt0ie1v60zicazeuwp31c4ro0.jpg


Both of the groups pictured above were fired from barrels with 1:7.7" twists.


So find a bullet that your barrel likes, and then you can start making adjustments with different charges of different burning rate powders.

If you're loading for terminal ballistic properties, that's a whole nother ball game.

Yes SIR! Thank you!!!

I would most definitely like to see a similar post precisely about terminal ballistics.

My predisposition is to always try to make super accurate rounds but I built this SBR precisely to do something different. In other words extreme accuracy is a secondary concern. I would actually say terminal ballistics would be primary actually.

Again, I don't want to throw out accuracy completely, but terminal ballistics is more what I am aiming for. It would be nice to have the best of both worlds... or a good compromise.

DeviantLogic
20 December 2015, 19:22
I just wonder if a low velocity 75 grain shot would be more destructive than a faster 55 grain...

Should be able to calculate energy upon impact. Energy = mass x velocity2. Think in terms of 200/300 yards and not 10 ft from the muzzle.


I have done some google fu and with a standard 55 grain bullet muzzle velocity will be around 2500 fps out of a 10.5 barrel.


If I go with the 75 grains based on the hogdon reload data and a little bit of guesswork I would be right around 2000 fps.

I'd be really surprised if there was a 500fps difference between the a 55gr and 77gr.

DeviantLogic
20 December 2015, 19:25
Molon is the man...that's all I gotta say [:D]

alamo5000
20 December 2015, 19:29
Hell, I could be completely wrong. But I know what I don't know so here I am asking LOL!

I do understand that under a certain level of velocity projectiles will not expand or perform as intended... so based on my own deductive reasoning if I did create a 77gr load...at the same time I would be decreasing the range where terminal ballistics would be adversely effected.

I just don't know all those details and I don't want to be wandering around in space forever trying to figure it out.

If I can shoot 2 inch groups at 100 yards and have effective bad ass terminal ballistics at that range then I am happy with that. For this rifle I don't need dime size groups. That said although the thought of having a heavy load (77gr) sounds on paper to be awesome I still want to know more about the lighter loads too.... 55 gr... 62gr... I am just not sure...

It's better to ask than to feel around in the dark.

alamo5000
20 December 2015, 19:30
Molon is the man...that's all I gotta say [:D]

^^^ What he said.

DeviantLogic
20 December 2015, 19:37
It's better to ask than to feel around in the dark.

Absolutely! I love the thought process in reloading. Trying to think through it along with you :)

alamo5000
20 December 2015, 19:50
Absolutely! I love the thought process in reloading. Trying to think through it along with you :)

At least my inquisitive nature isn't irritating EVERYONE LOL!!!

I am just thinking out loud here but if I did create a load with a 77gr bullet ....in a strict measure of terminal ballistics it might only be 'really' effective for 50 or 60 yards. That of course is pure 110% speculation.

Which I came to that conclusion merely by looking at a ballistics chart with some estimated numbers.

That then leads me to considering lighter rounds IE 55gr...

It might be splitting hairs but I want a stable bullet that has good terminal performance and pretty good accuracy out to at least 100 yards.

I will be using a supressor so I need to take that into account (definitely needs bullet stability) I also will not use a bipod or anything. I have an Aimpoint T2 on the way so my goal here with this set up is to be minute of man. Point and get on target and blast. Accuracy yes, but it is not primary.

That said if I am ever trying to kill a hostage taker who is standing behind a hostage I want to hit him not her. In other words I will never be in that situation so it won't matter.... but I want to make a load that will do it.

alamo5000
20 December 2015, 20:07
For example I made some numbers up and plugged them into a ballistics calculator.

I figured out of a 10.5" barrel I might get roughly 2500 fps using 55gr bullets.

https://c2.staticflickr.com/6/5641/23880230575_073d4d18c2_o.jpg

If you notice at 100 yards I still would have over 2100 fps which I am sure would be enough to do major damage.

That would be about equivalent of shooting a bad guy at 250 yards with a 55 grain bullet out of a 16" gun.

https://c2.staticflickr.com/6/5717/23253552693_d65f25c278_o.jpg

alamo5000
20 December 2015, 20:26
Maybe Molon can come back and look at my posts and tell me if I am full of shit or not [:D]

DeviantLogic
20 December 2015, 21:07
We don't need Molon for that [BD]

I did a lookup on what to expect on muzzle velocities for 10.5" barrels. Expect a muzzle velocity drop of 300-350 fps across the board. Main point of reference is http://www.sadefensejournal.com/wp/?p=1093

Pulled out my Sierra reloading manual, going off the second column. For 55 gr = 2800 fps, 77 gr= 2500 fps. Take off 350 fps and you're then looking at 2450 fps and 2150 fps.

Plug in the data to Hornady's online ballistic calculator for Sierra 55 gr BlitzKing and Sierra 77 gr MatchKing.

Below are the results I got. Again...I'd take the 77gr [:D]

https://farm1.staticflickr.com/668/23772767442_5aafbcf087_o.jpg (https://flic.kr/p/CdHDwJ)

https://farm6.staticflickr.com/5689/23798612731_84495a821b_o.jpg (https://flic.kr/p/Cg17ra)

alamo5000
20 December 2015, 21:18
We don't need Molon for that [BD]

Hardy harr harrr harr !!! LOL HAHAAA!!!

It's worth taking a look at either. Another aspect is cost. The 55 gr is plentiful and cheap. The 77 is much more expensive on a per round basis.

At the end of the day though it's kind of cool that we are able to come up with these possibilities.

I did hear/read somewhere that a 77 gr bullet will not fragment below 2100 fps or something like that. I don't know the exact number...so based on that that would make the terminal ballistics of that really bad ass 50 yards and in... not that I would care to be shot with it at any range.

Again Molon needs to get back on here and let us know these things :)

But if a 77 won't fragment under 2100 fps (or whatever that number is) that kind of limits it for my wants... whereas with the 55gr it's still going to do what it will do out to and past 100 yards (per my requirement)

This is definitely going to need more brain power and time... and of course experimentation....

alamo5000
20 December 2015, 21:23
http://www.m4carbine.net/showthread.php?38754-Ballistics-on-a-10-5-quot-barrel/page2

Read the second response down...

alamo5000
20 December 2015, 21:27
From the 'other site' that I just found....

https://www.ar15.com/archive/topic.html?b=3&f=16&t=363223

"A much more realistic threshold for reliable fragmentation with the 75-77 grain OTM loads is 2,250 FPS. From your 10.5ā€¯ barrel, this will give you a fragmentation range of approximately 48 yards."

(found about 10 posts down the page)

alamo5000
20 December 2015, 21:44
At this point I am looking at 'which' 55gr to start tinkering with :)

I might even go 50gr....

Or a 55gr soft point... ???

Slippers
21 December 2015, 05:06
You should check with markm. He's done some fragmentation tests with the 77 smk out of SBRs. I believe he found it still fragments fine at 100-150 yards with a short barrel.

Also, do keep in mind that devgru use mk262 (77 smk) for training and 70 gr Barnes tsx for shooting bad guys, and they use a lot of SBRs. If it wasn't lethal, they would not be using it.

alamo5000
21 December 2015, 05:47
You should check with markm. He's done some fragmentation tests with the 77 smk out of SBRs. I believe he found it still fragments fine at 100-150 yards with a short barrel.

Also, do keep in mind that devgru use mk262 (77 smk) for training and 70 gr Barnes tsx for shooting bad guys, and they use a lot of SBRs. If it wasn't lethal, they would not be using it.

Another reason I'm on wevo :)

I dont recall seeing markm around but f you do pass the word.

I would like to hear his input. The more the better.

Molon
21 December 2015, 16:05
I figured out of a 10.5" barrel I might get roughly 2500 fps using 55gr bullets. . .

If you notice at 100 yards I still would have over 2100 fps which I am sure would be enough to do major damage. . .





The established fragmentation threshold for M193 (determined through extensive testing by actual experts in the field of terminal ballistics such as Dr. Martin Fackler) is 2700 FPS. Below a striking velocity of 2700 FPS the M193 projectile will not reliably fragment and instead will simply yaw 180 degrees and travel base forward.




https://app.box.com/shared/static/ll89r4wviyezl4xworvdpkstcr47el0w.jpg





The wound profile of the M193 projectile striking at 2650 FPS is little better than the wound profile from a .22 LR. Ask yourself, would a .22 rimfire be your first choice for a self-defense load?





https://app.box.com/shared/static/vo7vhcukod.jpg





Even when the M193 projectile has a striking velocity of 2700 FPS or higher, it’s only going to perform “as advertised” approximately 15% of the time. The other 85% of the time, the ballistic neck (the distance that the bullet travels in tissue before bullet upset occurs) is so long that the bullet will have passed through much of or all of the body before fragmenting.




https://app.box.com/shared/static/9gmebfjy76.jpg




Fackler, ML: “Literature Review”. Wound Ballistics Review; 5(2):40, Fall 2001


“In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle. The man walked in to my clinic with no limp whatsoever: the entrance and exit holes were about 4 mm across, and punctate.

X-ray films showed intact bones, no bullet fragments, and no evidence of significant tissue disruption caused by the bullet’s temporary cavity. The bullet path passed well lateral to the femoral vessels. He was back on duty in a few days. Devastating? Hardly.

The wound profile of the M193 bullet (page 29 of the Emergency War Surgery—NATO Handbook, GPO, Washington, D.C., 1988) shows that most often the bullet travels about five inches through flesh before beginning significant yaw. But about 15% of the time, it travels much farther than that before yawing—in which case it causes even milder wounds, if it missed bones, guts, lung, and major blood vessels. In my experience and research, at least as many M16 users in Vietnam concluded that it produced unacceptably minimal, rather than “massive”, wounds.

After viewing the wound profile, recall that the Vietnamese were small people, and generally very slim. Many M16 bullets passed through their torsos traveling mostly point forward, and caused minimal damage. Most shots piercing an extremity, even in the heavier-built Americans, unless they hit bone, caused no more damage than a 22 caliber rimfire bullet.”




With all the advancements that have made in bullet technology over the last decade, the 55 grain FMJ bullet is a very poor choice for a self-defense load.

I personally only use factory loaded ammunition for my self-defense loads. That being said, if you’re going to hand-load ammunition with an eye toward terminal ballistic properties, here are a few things that you might want to consider.


to be continued . . .


...

voodoo_man
21 December 2015, 16:42
https://youtu.be/HODSWc_Nid0

alamo5000
21 December 2015, 16:57
OK so I am back to 77gr????

I wonder about say like a 40gr soft point or other varieties of bullets...out of a 10.5 barrel this whole ballistics thing gets interesting.

I basically want to shoot what I shoot. In my other rifle I have one load. That's it. No rezeroing. None of that.

I just wonder if there is a 'really good' all around projectile?

Whatever I end up deciding on I am just going to buy and make a bunch of those loads.... so far there is strong evidence that says 70-77 grain range is a the better option.

BoilerUp
21 December 2015, 17:13
Hmmm...I've been considering 62gr Gold Dots (Federal Fusion) as my go-to home defense round for 5.56. My understanding is that it gives good expansion plus barrier performance. Unfortunately, I don't think the bullets are readily available for rolling your own.

alamo5000
21 December 2015, 17:17
Hmmm...I've been considering 62gr Gold Dots (Federal Fusion) as my go-to home defense round for 5.56. My understanding is that it gives good expansion plus barrier performance. Unfortunately, I don't think the bullets are readily available for rolling your own.

Are you trying to do that out of a 10.5 SBR?

I can find all kinds of bullets... I am just wondering which ones are going to be most wicked :)

Hard to argue with voodoo man or slippers... but I am just wondering and trying to figure out what to get and/or roll for a 10.5 rifle.

alamo5000
21 December 2015, 17:29
This is my first SBR but this thread might should be mandatory reading for anyone considering an SBR... 11.5 or 12.5 opens up a lot of world when it comes to terminal ballistics.

DeviantLogic
21 December 2015, 17:30
I wonder about say like a 40gr soft point or other varieties of bullets...out of a 10.5 barrel this whole ballistics thing gets interesting.

I think going to 40 grain would be going in the wrong direction from where you are building the load for. In my opinion, what you should be looking for in terms of a self defense load for this rifle is the energy transfer upon impact and what the bullet does on impact. The 77 grain wins in calculated energy, however you may look at variants around that weight and see if there's any bullets that do better than others in your rifle.

The "all around projectile" really depends on what you're shooting. If all the barrels have 1:7 or 1:8 twist rates, then I'd go with the heavier (70-77 gr) rounds. Have slower twist rates in the mix and I'd look at 55-62 gr.

All this talk about terminal ballistics for self defense makes me want to buy a 300blk upper.

alamo5000
21 December 2015, 18:13
I think going to 40 grain would be going in the wrong direction from where you are building the load for. In my opinion, what you should be looking for in terms of a self defense load for this rifle is the energy transfer upon impact and what the bullet does on impact The 77 grain wins in calculated energy, however you may look at variants around that weight and see if there's any bullets that do better than others in your rifle.

The "all around projectile" really depends on what you're shooting. If all the barrels have 1:7 or 1:8 twist rates, then I'd go with the heavier (70-77 gr) rounds. Have slower twist rates in the mix and I'd look at 55-62 gr.

All this talk about terminal ballistics for self defense makes me want to buy a 300blk upper.

I guess for a 10.5 I might should rethink the 100 yard benchmark that I arbitrarily set. I guess it can't be all things to all people. 50-60 yards might be a more fair benchmark for what is set up to be a CQB gun from the get go.

This certainly has me thinking about all kinds of barrel lengths. Of course I am going to run the hell out of the 10.5 and see what I come up with. I can always build another upper.

alamo5000
21 December 2015, 18:35
http://www.youtube.com/watch?v=bJ9nFehD4Xw

BoilerUp
21 December 2015, 19:00
Are you trying to do that out of a 10.5 SBR?

I can find all kinds of bullets... I am just wondering which ones are going to be most wicked :)

Hard to argue with voodoo man or slippers... but I am just wondering and trying to figure out what to get and/or roll for a 10.5 rifle.

I'm running 16" for now. Will probably move to SBR in the next year. The Gold Dots have a great reputation for LEO work and for performance out of SBRs. All hear-say from my perspective, but I used a 90 gr Gold Dot in 6.8 (Federal XM68GD) to put down a deer last month (16" ARP Scout) and the bullets reputation in the 6.8 community has led me to explore it more for other calibers. Since the Speer bullets are unobtanium as components for reloaders (what is available are pulls), the Nosler Tactical Bonded is a close competitor and is used in many LEO factory ammo offerings: http://shop.nosler.com/nosler-navigator/tactical-law-enforcement-defense/nosler-22-64-gr-bonded-performance-protected-point-w-cannelure-100ct.html

Do a google search on Gold Dot and SBR and you will get some interesting hits.

Personally, I'd only keep factory loads handy/ready for a HD situation anyway just to avoid that extra variable coming into play in a legal dispute.

DeviantLogic
21 December 2015, 19:18
Good video Alamo. I embedded the video in your post so we could view it without opening up another window.

alamo5000
21 December 2015, 19:52
Personally, I'd only keep factory loads handy/ready for a HD situation anyway just to avoid that extra variable coming into play in a legal dispute.


Good video Alamo. I embedded the video in your post so we could view it without opening up another window.

Thanks! I wish 'they' would fix the video link thingy so we don't have to remember code....

On a side note I got a little goody in the mail box this evening.... Aimpoint T2 :) I have to admit, first impressions are that it's awesome.


Really though all this worrying and stuff only matters until it matters. With a 10.5 barrel it is NOT designed to be a long range rifle. I just have to get used to that idea. This is completely new territory for me. I have never pulled the trigger on an SBR so all this is internet folk lore for now. I am sure if a bad guy got his ass blasted off at 50 yards with a 55 grain or a 77 grain bullet he would certainly know it.

What I want is to have a a single consistent load that I can shoot and be zeroed for. If I make a load of 77s that should be just fine. My main thing is I just want to have a stable bullet because I want to run a suppressor. Pitching and yawing and all that is unacceptable. Really though sometimes I think about this stuff until it gives me a headache.

I also need to come to the realization that no matter how bad ass all this stuff is my odds of having to shoot people is pretty low. Basically I will have a kick ass range toy I just have to enjoy it for what it is. I need to get the gun built first and then over time I can finish building the load. I just think that after thinking on it more MAYBE having a 100 yard 'threshold' might be too aggressive for a gun designed to fight in a phone booth.

That said I might buy me some 77s and see what happens :)

alamo5000
21 December 2015, 20:15
I have to add with a simple barrel swap I can do a 458 socom too... my upper is 458 compatible.

alamo5000
21 December 2015, 20:36
Back to the load though... that video got me thinking... powder choice might make a big difference.

I have a big tub of varget that I do my long range stuff with... that stuff is very hard to come by.

I also have a pound of H4895 which is a slight bit faster of a burning powder...

On the burn rate chart the 4895 is #87 and the varget is #99

I am wondering if using a faster powder (like the 4895) would be better or using a slower powder might produce better stability....

It's counter intuitive but MAYBE slowing things down some might be the right thing to do to in order for optimal function, dwell time, and bullet stability. I am really not sure.

It could take years to figure something like that out.

alamo5000
23 December 2015, 15:29
So I have bought a little bit of stuff...

I have Varget to play with and a left over pound of IMR 4895.

As for bullets I obviously have 69 grain SMK, I ordered some other bullets to try as well.

http://www.midsouthshooterssupply.com/item/000032279/22-Caliber-point224-Diameter-75-Grain-Boat-Tail-Hollow-Point-Match-100-Count

75 grain Hornaday

http://www.midsouthshooterssupply.com/item/0011522421/22-Caliber-point224-Diameter-77-Grain-HP-Boat-Tail-Custom-Competition-100-Count

77 grain Nosler

I am going to experiment a little and see which one works the best. Ideally if I can make the 75 grain work that would be great because I can get those by the bucket load cheap.

I am just wondering what if any terminal ballistics differences there might be or if I need to buy a pound of faster powder.

As it stands according to this chart here Varget is #99 on the list and IMR 4895 is #89.

http://www.lasc.us/BurnRatePrint.htm

I only ordered a limited number of bullets for me to experiment on but those are the three that I can try out for now.

I love the 69smk for long range shooting but I am talking about terminal ballistics inside of 100 yards...

I am also not sure about powder... there are so many choices it's just stupid. I will probably work a load up with all three using the IMR and see what I can get.

alamo5000
23 December 2015, 15:34
Another thing that gets me is all these gel tests are done at full power... why can't I see what they would do out down range at say 2000 fps or whatever....

alamo5000
23 December 2015, 15:44
Keep in mind my main goals with the load development are

1. bullet stability. I DO NOT want to tear up my new silencer by trying to shoot an unstable bullet out of an SBR.

2. Terminal Ballistics is second or at least knowing at what level and where and what range I can expect performance.

3. Extreme accuracy is third. I am not going to be shooting far or from rests for the most part so trying to get a tack driver would be nice but it's not the main goal.

BoilerUp
23 December 2015, 17:19
So, I infer that "barrier blind" isn't a requirement.

alamo5000
23 December 2015, 17:53
So, I infer that "barrier blind" isn't a requirement.

Define 'barrier blind'.... [BD]

I am still learning a bunch of the terminology that you guys use. Acronyms and such... I am not versed in tactical talk at all.

Truth be told 99% of the time this is going to be a plinker/range toy. I ain't gonna even try and lie about it. That said I would like to use my suppressor on the gun, but I won't even chance it until I KNOW the round is stable. 99% of the time this is going to be a fun target gun mainly because it's America and I can.

Depending on what you mean by barrier blind lay it on me so I can try to take that into account if possible.

If you know something I don't then by all means lay it on me. That's the whole point of having a thread.

EDIT: Googlefu found this:

http://www.homedefensegun.net/barrier-blind/

alamo5000
23 December 2015, 18:06
So, I infer that "barrier blind" isn't a requirement.

Again considering that it's a 10.5 SBR in .224... if you know of a good projectile/load that has all those characteristics please let me know.

alamo5000
23 December 2015, 18:10
If I am going for SD I should just build a 458 SOCOM upper with that extreme penetrator ammo.

Check out the video...start watching at 1:50

They rip a block of ballistics gel in two lengthwise...

https://www.youtube.com/watch?v=OVkWPerR6kE

Slippers
23 December 2015, 18:22
Bullet stability? 1:7 twist barrel and you're done. Nothing to worry about.

Powder burn rates will not make much of a difference in velocity. Very minor differences. And truthfully, you shouldn't be relying on reloads for self defense. Buy 75gr TAP or a good mk262 77gr clone like CBC or IMI razor core.

alamo5000
23 December 2015, 18:30
Bullet stability? 1:7 twist barrel and you're done. Nothing to worry about.

Powder burn rates will not make much of a difference in velocity. Very minor differences. And truthfully, you shouldn't be relying on reloads for self defense. Buy 75gr TAP or a good mk262 77gr clone like CBC or IMI razor core.

For plinking is what I am talking about... to make a generic load that will be stable for cheap. I am leaning towards the Hornaday bullets because they are like 15 cents a piece. Shoot more for less. I have some coming so I will try out 100 of them and see... same with the 77gr...

For SD I really like that 70gr barnes TSX that you mentioned earlier. I might buy a box or two of those for those just in case moments. Or the 77 gr black hills or whatever... I am sure all will get the job done. I just dislike having to rezero my rifle all the time.

So basically if I reload with the 75 grain hornadays and then buy some TAP for the real just in case.... that is a real possibility. Same grain, and hopefully same zero....

alamo5000
23 December 2015, 18:34
Bullet stability? 1:7 twist barrel and you're done. Nothing to worry about.

Powder burn rates will not make much of a difference in velocity. Very minor differences. And truthfully, you shouldn't be relying on reloads for self defense. Buy 75gr TAP or a good mk262 77gr clone like CBC or IMI razor core.

BTW my barrel is a 10.5 ballistic advantage with a 1:7 twist...

http://androcorpind.com/index.php?route=product/product&path=75_70_71&product_id=51

Slippers
23 December 2015, 18:34
I find if velocity is similar, the POI is usually really close at 100 yards.

alamo5000
23 December 2015, 18:46
I find if velocity is similar, the POI is usually really close at 100 yards.

I am coming from a baseline of my 16" gun... consider I have many seemingly stupid questions because I have never fired an SBR. Not even once. I will have one because it's America.

With my 16" gun if I swap grain weights I am all over the place. I can still hit the target but the POI is totally different. When I shoot my go to load (69gr smk) I can get well under sub moa... my best group was a 10 shot group that could be covered by a dime at 100 yards... I also was able to hit out to 800 yards with it. I'm frickin' phobic about it. It took me a while to get my rifle zeroed but now it goes where I want it to go.

I am having to completely throw out (for the most part) my thinking of that because I am going with a totally different style of gun.

Like I said, at present having reloads for the 75 grain hornadays if they work decent then I will buy a lot of them and shoot for cheaper.

I do keep on hearing about bullet stability out of short barrels. I see youtube videos with keyholes all over the place even with factory ammo...it's something I definitely want to address upfront. Until I am absolutely certain then I won't use my suppressor.

For this gun though I will probably zero somewhere between 25 and 50 yards...I arbitrarily set the 100 yard mark as my baseline but that was just picked out of the blue.

alamo5000
23 December 2015, 18:53
http://www.selwayarmory.com/hornady-bullets-22-caliber-224-diameter-75-gr-match-hollow-point-boat-tail-bag-of-2000.html

.14 cents a projectile ain't too bad. I will be maybe .20 cents or under per round which is a good thing... for a nice consistent round... That ultimately is what I am after.

And I want to make sure it's stable enough to use my suppressor, which now that I have beaten it like a dead horse, I am sure the 75 gr will be fine.

With this load having pinpoint precision is not primary. With my other gun, yes it is primary. With this gun I want it to be dead on accurate which would just be a bonus.

Doing all this out of an SBR seems like a different game than a regular length rifle though...

alamo5000
23 December 2015, 19:01
At the end of the day I just have to see which bullets the GUN likes...

When I was doing the load for my 16" gun when I hit 69gr SMK.... it was like magic.

I am just hoping that the gun likes cheap projectiles :)

RiverRat
23 December 2015, 23:33
I've started and stopped this post a half dozen times and I just can't stop myself this time - even though Will beat me to some of the punch.

Here is my viewpoint:

You haven't even built up this carbine yet. I believe you're grossly over-theorizing, particularly when unable to generate data.

I suggest you get your stamp, build the SBR, work out any kinks, attach the suppressor and tune if needed - all with a reputable factory ammo to establish a baseline. The likelihood of a good factory load close-range keyholing with your 1:7 barrel is very, very small. If anything, you'll overstabilize 55 gr, which won't matter at all for the ranges you should be considering with this rifle. But you can get real data when the gun is built. Then figure out how you're actually going to measure performance and start your test with a good M262 Mod 1 variant (Black Hills, CBC, IMI Razor Core), using those quantifiable endpoints. If it fails to perform as you would like, THEN consider alternatives to address shortcomings (likely with 77 SMK and 55 FMJ data already in hand).

Also consider that your secondary (defensive) objective for an optimal load is playing to the greatest weakness of an SBR (velocity). Sounds like a recipe for failure that would make me grab the 16" over the 10.5" without some specific need that short satisfies better (which is probably only a handful of scenarios and perhaps not worth agonizing over). Maybe this SBR is just a fun range/pit toy, which is still an excellent reason to build it.

alamo5000
24 December 2015, 04:07
I've started and stopped this post a half dozen times and I just can't stop myself this time - even though Will beat me to some of the punch.

Here is my viewpoint:

You haven't even built up this carbine yet. I believe you're grossly over-theorizing, particularly when unable to generate data.

I suggest you get your stamp, build the SBR, work out any kinks, attach the suppressor and tune if needed - all with a reputable factory ammo to establish a baseline. The likelihood of a good factory load close-range keyholing with your 1:7 barrel is very, very small. If anything, you'll overstabilize 55 gr, which won't matter at all for the ranges you should be considering with this rifle. But you can get real data when the gun is built. Then figure out how you're actually going to measure performance and start your test with a good M262 Mod 1 variant (Black Hills, CBC, IMI Razor Core), using those quantifiable endpoints. If it fails to perform as you would like, THEN consider alternatives to address shortcomings (likely with 77 SMK and 55 FMJ data already in hand).

Also consider that your secondary (defensive) objective for an optimal load is playing to the greatest weakness of an SBR (velocity). Sounds like a recipe for failure that would make me grab the 16" over the 10.5" without some specific need that short satisfies better (which is probably only a handful of scenarios and perhaps not worth agonizing over). Maybe this SBR is just a fun range/pit toy, which is still an excellent reason to build it.

But you're missing the point... "I over-think, therefore I am"... [BD]

It wouldn't be my post if I didn't agonize over dumb bullshit [:D]

That is my motto... just ask anyone LOL!!!

But on a serious note though look a couple posts up in this thread for the video by Hornaday and watch that one. It points out the stability issue.

I have also seen numerous videos and seen numerous posts about it and heard about it from numerous people who have even showed me pics of their bullets entering the target backwards or sideways. If the bullets keyhole or whatever.... I won't run my suppressor on it. Period. From all indications the 77 grain bullet is by far the most stable at those lower velocities, at least according to the online calculators and such.

I am starting from there merely because I don't want to F up a 900 suppressor. All the rest of the operator stuff can be sorted out later. But like I was saying, once I start doing a reload, I will do THAT reload. It makes life a lot easier when I can get one set of components and just roll with it. It's just bonus points that 77gr bullets also apparently have the best terminal ballistics from an SBR.

But you are right about me speculating. I do tend to do a lot of that. While I am agonizing over it I try to agonize over all of it just so that I can get it over with [BD]

alamo5000
24 December 2015, 04:13
My other motto is complaining about ATF wait times [BD]

alamo5000
24 December 2015, 04:51
You haven't even built up this carbine yet. I believe you're grossly over-theorizing, particularly when unable to generate data.

I suggest you get your stamp, build the SBR, work out any kinks, attach the suppressor and tune if needed - all with a reputable factory ammo to establish a baseline. The likelihood of a good factory load close-range keyholing with your 1:7 barrel is very, very small. If anything, you'll overstabilize 55 gr, which won't matter at all for the ranges you should be considering with this rifle. But you can get real data when the gun is built. Then figure out how you're actually going to measure performance and start your test with a good M262 Mod 1 variant (Black Hills, CBC, IMI Razor Core), using those quantifiable endpoints. If it fails to perform as you would like, THEN consider alternatives to address shortcomings (likely with 77 SMK and 55 FMJ data already in hand).


Also I should add if all goes well I will be shooting this gun on Saturday if all goes well (I hope). I will wrap the buffer tube with about 2 pounds of paracord and go pistol for a while until I can find an alternative.

After looking into it some I think I am glad that I did, because knowing my dumbass on day 1 I would put my suppressor on there and get a baffle strike. This gun will be unsuppressed (for now) until I am comfortable with what I wind up with ammo wise. I will do a lot of testing and tinkering in the mean time.... but my Wal Mart ammo does not get the suppressor treatment until I am (personally) sure about all that jive. If anything I have a couple hundred rounds of cheap ammo to test gun function to start with then I can, as you suggest, move on from there.

Slippers
24 December 2015, 05:50
I bet it drives you bonkers to know I shoot wolf steel case through my suppressor all the time. :)

Seriously, your fears are unwarranted.

Also, don't limit yourself to short ranges. I shoot out to 550 all the time with my 11.5. It's fun, and challenging. Short barrels tend to be at least as accurate as longer ones, you just lose velocity.

Dstrbdmedic167
24 December 2015, 06:03
^^ and I've been there and done it as well. With both his 11.5" and my 12.5". I may even try the new 8.2" wlv next time I get up there. Just because....

RiverRat
24 December 2015, 09:44
wrap the buffer tube with about 2 pounds of paracord and go pistol for a while until I can find an alternative.

A simple, short-term, zero impact, cost effective solution: http://www.thordsencustoms.com/

You can set your system up with the buffer tube and action spring you plan to use long-term. When you get your stamp, detach the Thorsden and slide on the stock.....done. The least expensive tube cover is something like $22 on sale this week.

alamo5000
24 December 2015, 10:00
I bet it drives you bonkers to know I shoot wolf steel case through my suppressor all the time. :)

Seriously, your fears are unwarranted.

Also, don't limit yourself to short ranges. I shoot out to 550 all the time with my 11.5. It's fun, and challenging. Short barrels tend to be at least as accurate as longer ones, you just lose velocity.


Bonkers? No way man. It makes me feel A LOT better to be truthful. I just dropped a lot of coin on a project that I'm not familiar with so in the end the shittier the ammo the better. Makes me feel a lot better. I will still do a load for my gun but I'm just making sure...

Dstrbdmedic167
24 December 2015, 10:04
As I always tend to tell you, you wayyyy over think things. I know tags your nature but a lot of it is not warranted.

Since it's so warm here today(80* and cloudy) I think I'll go shoot my new 8.2" upper on my SBR lower

alamo5000
24 December 2015, 10:17
As I always tend to tell you, you wayyyy over think things. I know tags your nature but a lot of it is not warranted.

Since it's so warm here today(80* and cloudy) I think I'll go shoot my new 8.2" upper on my SBR lower

I hate not knowing and when I don't know I dwell on it...that is unless I don't give a shit about it in which case I just forget about it.

I really am glad you guys are reassuring me. Seriously.

alamo5000
25 December 2015, 12:55
https://c2.staticflickr.com/6/5822/23341019564_aaae8aa81b_c.jpg

Runs like a champ. Had a few minor hiccups to start... working out the minor bugs.

One was that I did not adjust the gas block so I was having to manually charge after each round. After 2 minutes of head scratching I said to myself... 'let me try this'...and now it works just fine.

It is still a little tight. Sometimes the bolt locks back after the last round and it's pretty tight to release.... I imagine little things like that will work itself out as the gun is broken in.

And yes, I shot some federal 55 grain wal mart ammo through it and it works fine. And yes, I did shoot some through the suppressor :) Again no problems to speak of.

I will say this though... I haven't tinkered with the gas system or even zeroed the aimpoint but surprisingly the aimpoint is pretty good. It's on steel although about 8" low at 50 yards. The gas system though, I cranked it all the way to 12... then backed off to 10 and I might back off some more to see where the sweet spot is... with my 16" gun setting 7 is perfect.

Also I moved the AFG back a couple notches because the screw was riding the gas block. I just did the above mock up of the upper for pictures.