Build Help!

[TommyValkyrie]

What billet upper are you going with? If it's a Mega, you might have issues. I'm not positive (someone else might be able to clarify), but the Mega billet uppers don't usually work with Geissele rails without modification.

I'm building a Mega billet rifle right now, and I decided on the Parallax Tactical M-lok handguard because the Geissele rails require machining of the upper receiver.

I do have a Mega billet on the way, should be here Tuesday gods willing

[FortTom]

I would stick with the 5.56 platform vs 300 BLK if this is your build. The costs associated with 300 ammo might turn you off on the platform. Besides, unless you are suppressed and/or shooting a short barrel, I think the benefits of 300 BLK are wasted.

I bought .300blk for deer hunting, and really, the novelty has worn off. Have contemplated selling my .300blk barrel for a while now. I agree, if it's not suppressed or short barrel (or both) the benefits are wasted. I was uneducated at the time I built mine. It's a fine gun, but it does nothing more than what the same gun in 5.56 could do, IMO, and costs more to shoot.

I see a lot of that going on around here. I got offered a barrel, piston drive, and hand guard about a week ago, for probably a third or less than the guy paid for it, and still took a pass... I'm just throwing this out there, but I believe the 300BLK is a better round for the CQC commando types. For me personally, as a civilian, I could never really learn to care for it much..Just curious, if I read your post correctly, this is your first build? You don't have to justify anything to me, but I'm curious as to why this cartridge was your first pick.

If it's not to late, I would take UWone77's and Ride4frnt's advice into serious consideration.

Either way, good luck.

[CarbonScoring]

I do have a Mega billet on the way, should be here Tuesday gods willing

The Geissele rails and Mega billet uppers look great together (nsz85 did this combo). Just be prepared to take the upper to a machinist to get it milled to fit the rail.

[TommyValkyrie]

The Geissele rails and Mega billet uppers look great together (nsz85 did this combo). Just be prepared to take the upper to a machinist to get it milled to fit the rail.

That video is actually what made me decide to go with Mega and a geissele, as a matter of fact.

I see a lot of that going on around here. I got offered a barrel, piston drive, and hand guard about a week ago, for probably a third or less than the guy paid for it, and still took a pass... I'm just throwing this out there, but I believe the 300BLK is a better round for the CQC commando types. For me personally, as a civilian, I could never really learn to care for it much..Just curious, if I read your post correctly, this is your first build? You don't have to justify anything to me, but I'm curious as to why this cartridge was your first pick.

If it's not to late, I would take UWone77's and Ride4frnt's advice into serious consideration.

Either way, good luck.

I am debating what to do, and I will until I actually purchase the barrel. A little off topic, but do you guys no what type of performance I could expect out of a 5.56, and a .223 out of a 16" barrel?

[Dstrbdmedic167]

I am debating what to do, and I will until I actually purchase the barrel. A little off topic, but do you guys no what type of performance I could expect out of a 5.56, and a .223 out of a 16" barrel?

Elaborate on what you mean by performance? That depends a lot on the actual barrel you go with. I had a psa 16" 5.56 that would shoot 2 MOA at 100yds and yielded well over 3000 fps. My 12.5" arp 223 Wylde will do 2800 and get me .5" MOA at 100yds. Both were with my reloads that were just plinking style reloads( ie- 55gr fmj auto loaded)

[TommyValkyrie]

Elaborate on what you mean by performance? That depends a lot on the actual barrel you go with. I had a psa 16" 5.56 that would shoot 2 MOA at 100yds and yielded well over 3000 fps. My 12.5" arp 223 Wylde will do 2800 and get me .5" MOA at 100yds. Both were with my reloads that were just plinking style reloads( ie- 55gr fmj auto loaded)

I plan on using almost entirely commercial ammo. I do live in a city, or rather, just outside of one. So anything over a MAX of 200 yards is useless to me for this build. I plan on a long range 308 build once I'm finished, but this will be more of a CQC build, one of the main reasons I decided on 300blk initially.
I was always afraid of approaching a 5.56, because all I ever hear is that they just tumble out of anything other than 20" and up. I'm more interested in 75-100 yard performance, so for my needs (Or rather, wants) for this rifle, I just keep thinking that 300blk would fit best.

[Ride4frnt]

I plan on using almost entirely commercial ammo. I do live in a city, or rather, just outside of one. So anything over a MAX of 200 yards is useless to me for this build. I plan on a long range 308 build once I'm finished, but this will be more of a CQC build, one of the main reasons I decided on 300blk initially.
I was always afraid of approaching a 5.56, because all I ever hear is that they just tumble out of anything other than 20" and up. I'm more interested in 75-100 yard performance, so for my needs (Or rather, wants) for this rifle, I just keep thinking that 300blk would fit best.

Think of cost as well. .300blk will break you. And it's not as readily available. Inside 200yds you could shoot 5.56 accurately with irons (no groups, but you could hit a body sized target) .300 is gonna perform best with a suppressor.

[Dstrbdmedic167]

I plan on using almost entirely commercial ammo. I do live in a city, or rather, just outside of one. So anything over a MAX of 200 yards is useless to me for this build. I plan on a long range 308 build once I'm finished, but this will be more of a CQC build, one of the main reasons I decided on 300blk initially.
I was always afraid of approaching a 5.56, because all I ever hear is that they just tumble out of anything other than 20" and up. I'm more interested in 75-100 yard performance, so for my needs (Or rather, wants) for this rifle, I just keep thinking that 300blk would fit best.

Couldn't be farther from the truth.. I have had a 7.5" pistol and still didn't have any tumbling issues even out to 100 yds. (never went much further with that one) I'll say it like this it is THE round our military and LEO use.( take that as you want but it's a positive to me) Yea the 300 is a lot bigger bullet but of you think about it which is likely to tumble first? A small 55-62gr projectile or a 125-220gr projectile in essence the same case? especially if your planning a CQB type build and looking for 100yds or less in most cases the 5.56 is and will be the way to go. You will also spend A LOT less money of 5.56 - ammo vs 300blk ammo. I'm building a 300 blk SBR now. But only because I plan to solely run it suppressed and subsonic. Otherwise I'll stick to my 5.56 or wolverine for CQB, 6.8 for average range and 308 if I really need to get out there... Just my $.02...

[TommyValkyrie]

Couldn't be farther from the truth.. I have had a 7.5" pistol and still didn't have any tumbling issues even out to 100 yds. (never went much further with that one) I'll say it like this it is THE round our military and LEO use.( take that as you want but it's a positive to me) Yea the 300 is a lot bigger bullet but of you think about it which is likely to tumble first? A small 55-62gr projectile or a 125-220gr projectile in essence the same case? especially if your planning a CQB type build and looking for 100yds or less in most cases the 5.56 is and will be the way to go. You will also spend A LOT less money of 5.56 - ammo vs 300blk ammo. I'm building a 300 blk SBR now. But only because I plan to solely run it suppressed and subsonic. Otherwise I'll stick to my 5.56 or wolverine for CQB, 6.8 for average range and 308 if I really need to get out there... Just my $.02...

Think of cost as well. .300blk will break you. And it's not as readily available. Inside 200yds you could shoot 5.56 accurately with irons (no groups, but you could hit a body sized target) .300 is gonna perform best with a suppressor.

I do plan on suppressing it, but I do want to be able to use supersonic as well. From the guys I've talked to, 300blk supersonic hits pretty damn hard. However you guys are starting to push me towards 5.56, so now I'm all over the place.

[CarbonScoring]

Are you just going to be punching paper, or do you need a harder hitting round?

For a home defense rifle, I believe either round would be better than pistol calibers. If, like me, you are going to be shooting 99.999999% (hopefully 100%) of the time at the range, 5.56 is probably a better choice.

As for performance, most quality, 16" barrels should be able to do 1 MOA at 100 yards. Look at the Mega or Rainier Match barrels.

[GOST]

I personally wouldn't go with 300 BO unless I was building an SBR, and was reloading.

[TommyValkyrie]

I personally wouldn't go with 300 BO unless I was building an SBR, and was reloading.

I may or may not SBR it at some point, around 10.5 inch barrel. I have been wanting to reload for a long time but I'd have no idea where to start or what I was doing.

Are you just going to be punching paper, or do you need a harder hitting round?

For a home defense rifle, I believe either round would be better than pistol calibers. If, like me, you are going to be shooting 99.999999% (hopefully 100%) of the time at the range, 5.56 is probably a better choice.

As for performance, most quality, 16" barrels should be able to do 1 MOA at 100 yards. Look at the Mega or Rainier Match barrels.

I do want something that hits a little harder, I'm just not a fan of the AK platform. I will be punching holes in plenty of paper though as well. I plan on getting some serious training down the road too.

[UWone77]

First,

I would not shoot 300 supersonic out of a pistol can. Most of them are only rated for subs. Regardless, I shoot rifles rounds out of my rifle cans.

I'd still stick to 5.56. If you really want 300 down the road, do a barrel swap or an upper swap. The distances and the type of shooting you seem to want to do, I'd just get myself a quality CHF barrel, Daniel Defense, BCM, Rainier Mountain Series, ect and call it a day.

[TommyValkyrie]

First,

I would not shoot 300 supersonic out of a pistol can. Most of them are only rated for subs. Regardless, I shoot rifles rounds out of my rifle cans.

I'd still stick to 5.56. If you really want 300 down the road, do a barrel swap or an upper swap. The distances and the type of shooting you seem to want to do, I'd just get myself a quality CHF barrel, Daniel Defense, BCM, Rainier Mountain Series, ect and call it a day.

I wouldn't shoot supersonic anything out of a can. Watched a guy I knew shoot 5.56 supersonic out of a 9mm can, didn't end well. The osprey however, is rated for 300 subsonic

[WHSmithIV]

I thought originally to build a .300 blackout pistol. It would actually be one of the most perfect bedside home defense weapons especially with subsonic rounds. However, to use it outside the home for other things would be cost prohibitive due to the cost of ammo. That is one of the reasons I've changed the design to be a 7.62x39 - ammo is much cheaper. I also changed the plan on barrel length so that the pistol build won't be too much of a flamethrower. What use is a flash hider with so much flash that still throws so much flame that it's still a flame thrower? This is a problem I've been wrestling with. I want the 7.62x39 to be an actual pistol build but I don't want so darn much flash from it that I can't see at night when I use it. A 10.5" barrel seems like it 'might' work, but I'm not even really sure of that. I know a 7.5" or 8" barrel simply wont give the cartridge enough time to burn off the powder and it would be a flame thrower.

There simply isn't yet enough data available publicly posted for barrel lengths, flash emitted and calibers for rifle cartridges used as pistol configurations.

Well, I'm going to build this one with my best guess. Then I will publish data on how well it does the job with factory available and military surplus ammo. One thing is for sure, it WILL eat anything I feed it.

We all buy the parts we like and can afford to make our guns the way we want them to be. Technically there isn't a lot between what is available and there is MOST certainly a LOT of options available. AR's are Lego kits for adults. Your parts list is good. Build it! Then show us all pictures and a range report.

I can't give you specific info on the parts you have. I am not a type 7 FFL who builds custom guns. I just build my own and I haven't used any of the parts in your list. Your parts list does look good though and I would build one from them.

-Will-


Edit:
You build what you want. Just use milspec and decent components. That's all you really need to do. How many rounds do you expect to put through it in the next 10 years? Just because some parts are eye candy that doesn't mean that they are actually any better than less expensive parts that are not eye candy. Those less expensive parts often get the job done just as well or even better than the more expensive parts. I worked in an Aluminum factory for several years. The raw metal is extruded into more workable smaller pieces. There really is no difference whether a lower receiver is forged or a billet (a billet is simply worked from a block that is cut from the block rather than being melted into it's primary shape). Melting into the primary shape or forging it, metallurigically, with aluminum there will be no difference as to strength using the same same T rating of the metal. Billet made will simply have a nicer external finish. A more 'satin' type of finish. The metal will work the same and actually the cheaper forging will be just a tad stronger since the molecules of the metal will have aligned in the forging. Forging is melting metal into its final shape. Trying to compare a forged OR billet receiver to a polymer one is really like comparing an apple to a daisy. Comparing a forged or billet receiver really is like comparing two very close types of apples together. Fit is always determined by the quality of the machining, not by which version of the metal was used. Anodizing is what provides the hardening finish and the chemicals used for that anodizing will determine how 'satin' the finish is - but that's all. It won't provide a stronger receiver.

So, for those of you with a tight budget, there is no need to buy billet receivers that cost more for them to have that more satin finish. Buy the forged parts. You need a reliable and functional gun. For those of you with cash to spare and build guns to make them look and have a great external finish, buy the billet receivers. Functionality from either type of receiver wont change and neither will the strength of the metal.

Will