Load Development for an SBR

[DeviantLogic]

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]

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]

[BoilerUp]

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-naviga...ure-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]

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

[alamo5000]

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]

I have to add with a simple barrel swap I can do a 458 socom too... my upper is 458 compatible.

[alamo5000]

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]

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.co...atch-100-Count

75 grain Hornaday

http://www.midsouthshooterssupply.co...tion-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]

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]

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]

So, I infer that "barrier blind" isn't a requirement.

[alamo5000]

So, I infer that "barrier blind" isn't a requirement.

Define 'barrier blind'....

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]

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]

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