AR-15 in .300BLK (300 Blackout)

[Slow Hand]

Well, since my .300BLK upper is officially done now, I'll go ahead and drop a couple pics:

Looks good. Is it a semi auto now or still a straight pull bolt action? ;-)

 

[42769vette]

Looks good. Is it a semi auto now or still a straight pull bolt action? ;-)

i ask the same question yesterday. best looking single shot ive ever seen

 

[shooter521]

Looks good. Is it a semi auto now or still a straight pull bolt action? ;-)

i ask the same question yesterday. best looking single shot ive ever seen

I blame Cwood.

Hopefully I'll be able to sneak in a test-fire on Monday, now that it has been fixed.

 

[shooter521]

Hopefully I'll be able to sneak in a test-fire on Monday, now that it has been fixed.

Update – Not fixed.

Shooting Rem L300AAC2 (115gr CTFB), I had consistent failures to feed, where the fired case would eject, but the bolt would close without picking up a new round from the mag. Tried a different BCG and magazine and things improved somewhat, but still had intermittent feed failures. I'm sort of at a loss. The original BCG appears good - I believe it's an LMT unit, gas rings are intact and gas key is properly staked. I'll have to do some further experimentation with different mags and ammo.

What buffer weights are y'all running with the .300BLK pistol-length gas systems?

 

[byggpoppa]

H2 as per AAC.

 

[mammynun]

Update – Not fixed.

Shooting Rem L300AAC2 (115gr CTFB), I had consistent failures to feed, where the fired case would eject, but the bolt would close without picking up a new round from the mag. Tried a different BCG and magazine and things improved somewhat, but still had intermittent feed failures. I'm sort of at a loss. The original BCG appears good - I believe it's an LMT unit, gas rings are intact and gas key is properly staked. I'll have to do some further experimentation with different mags and ammo.

What buffer weights are y'all running with the .300BLK pistol-length gas systems?

I'm having the same issue. I've tried 3 different buffers (carbine, H1 and H2) and springs that all work flawlessly in a RRA 5.56. All the spring/buffer combos seem to drag in my Palmetto State pistol receiver extension (hurry form 1!!!!)
Mine works a lot better with USGI mags than Magpuls (20 or 30 rounds), but still no where near 100%. I have some different ammo (only fired Gunn so far) , but haven't tried it yet...
The bolt locks to the rear with a single round in the mag.
I'm hoping more rounds and a proper receiver extention will solve my problems.

ETA: http://dsgarms.com/ProductInfo/NVU-10RH-300BLK.aspx is my upper, Noveske blem lower with a pistol PSA lpk.

 

[Hop]

These sound like they are on the verge of being under-gassed. What size it the gas port on these guns? Barrel length? Gas system length? If I had a suppressor that could handle super sonic I'd let you try it and see if they cycle.

 

[OneBadV8]

I was wondering the same thing as Hop. Would a different Flash Suppressor/Muzzle Brake that created more pressure help? Like the Noveske Pig (KX3)

 

[shibumiseeker]

I've got a 16" with a carbine length gas system I built and it runs perfectly as is, but when I put IndyMonkey's YHM Titanium can on it it would have occasional failures to return fully into battery with both my 150gr loads and subsonic loads. My guess is increasing the dwell time is screwing up the lock timing.

If you are running a pistol length gas system with your rig (what's the barrel length?) you may be getting too much dwell and it could be undergassed as Hop noted, or it could even be overgassed as either will affect the timing. Since it's easier to play with buffer weights try those first, but this is an area where adjustable gas blocks are really handy. Optimally the buffer weight is tuned to the proper gas amount and dwell time and there's an intersection area where it will run, but being near the middle of that area makes it run the most reliably under varying conditions. But you probably already know all of that.

 

[shooter521]

Mine is an 11.5" barrel with a pistol-length gas system.

 

[mammynun]

Mine's 10" with an AAC Blackout FH, waiting on the SDN-6 to get out of "jail." I suspect (hope?) that my issue is being caused by excessive drag from the pistol receiver extension. It is noticeably harder to cycle when using the CH.

 

[KLB]

I think I am going to have to start looking into a .300BLK SBR with a suppressor. It just looks like too much fun to pass up.

 

[shooter521]

Blackout bump!

Just got this accessory as a gift from esrice for hosting his SBR upper for the past year or so... works well with the whole black-and-silver scheme that I've got going on here. Thanks, Evan!

 

[patience0830]

AR10A4 .243 RIFLE MOLY BBL ASY POST BAN COMPLETE ASSY

AR-10 chambered in .243 Winchester is a fabulous all purpose rifle in part because of the all purpose .243 Winchester cartridge. The .243 Winchester is ultra accurate and outperforms other varmint type ammunition. This round fits the AR-10 platform with no alterations and has much less recoil than the 7.62 NATO.
Caliber: .243 Winchester
Barrel: 20" Inch Match Grade Chrome Moly Barrel
Rifling Twist: 1:10 RH
Muzzle Device: None
Front Sight Base: Picatinny Gas Block, Top of gas block is .398 (+/- .010) lower than top of receiver

Your Price: $425.00 EA

You gotta have an AR10 sized lower for .243 Win.

Now .243 WSSM( WSM?) will fit the AR15 platform lower with the right upper.

 

[jblomenberg16]

Blackout bump!

Just got this accessory as a gift from esrice for hosting his SBR upper for the past year or so... works well with the whole black-and-silver scheme that I've got going on here. Thanks, Evan!

Very nice! Wonder if he'll loan out his stencil...I've been looking at doing something similar, just haven't found a good stencil yet.

 

[esrice]

Thanks, Evan!

Thank YOU sir! I really appreciate all of your help and AR/NFA guidance.

Very nice! Wonder if he'll loan out his stencil...I've been looking at doing something similar, just haven't found a good stencil yet.

Later I'll post up a how-to for this. It wasn't nearly as easy as I was anticipating.

 

[jblomenberg16]

Later I'll post up a how-to for this. It wasn't nearly as easy as I was anticipating.

Looking forward to it, as I've not be successful yet either.

 

[42769vette]

Later I'll post up a how-to for this. It wasn't nearly as easy as I was anticipating.

defintally do that, thats one of the hesitations i had about getting a blackout was the possibability of puttting the wrong mag in the wrong gun.

i was going to buy some tan pmags but your mag looks coolier

 

[JonProphet]

Subscribed. Just read all 28 pages of this. Me thinks, I'm going to be drinking the kool-aide for my new stripped lower. Time will tell!

Question, is 16" the longest barrel you can get? I'm not a big fan of the shorties. Also, on the can side of things, if I wanted to go supersonic, would I need a different can? This is all hypothetical for me, as all I have at this point is a stripped lower that I want to slowly build.


-JD-

 

[dagibson1507]

I'm pretty sure one of the sight supporters teased a 18" barreled upper around christmas. As far as a can you would need a full power 308 can or at least the huntertown ak rated can.