AR-15 in .300BLK (300 Blackout)

[usmcgt1371]

Where can I find the barrel conversion for the. 300 blackout for my stag model 2t? Asap

 

[sgreen3]

play suppressed, it will mainly be a demo rifle

, sounds like it will be one sweet rifle Vette! cant wait to hear how the build goes for ya

 

[42769vette]

, sounds like it will be one sweet rifle Vette! cant wait to hear how the build goes for ya

my goal is to have it done by the 1500 so i better finish ordering parts tomorow. obviously the suppressor will take a bit longer

 

[esrice]

Where can I find the barrel conversion for the. 300 blackout for my stag model 2t? Asap

All you would need is a .300BLK barrel. Check Noveske, CMMG, Spike's Tactical, etc.

 

[jblomenberg16]

Thread hasn't been active for a while, so thought I'd bump with some recent information.


My buddy got his YHM can last week, so we've been doing some testing with it to find some good subsonic loads that will cycle reliably. The test gun is a 16" CMMG upper with Carbine gas system, identical to mine, which I posted earlier in the thread. So far we've been successful with 208gr A-max, and 180gr lead round nose hunting bullets for 30-06 bolt guns.


A few things we've learned:

• Niether the 208A-max or the 180gr soft point expands at subsonic velocities when shot into water jugs. In fact, the 180gr soft point we managed to catch in a juge was clean enough and in good enough shape it could have probably be shot again!

• The 180 gr soft point will pennetrate 3+ gallon jugs of water at point blank range. (Video to come soon if I can get it off my phone)

• Seating depth seems to be a key factor in reliable cycling for subs as well as reliable velocity. We got more consistent velocity and more reliable cycling with bullets seated DEEPER in the case. When loaded to mag length and with the same powder charge, we could not get reliable cycling. We also noticed that the rounds seated to mag length would pick up velocity with each round. Our theory was that the heat from the previous round was heating the powder and air gap between the powder and bullet and hence changing the pressure curve.

The seating depth discovery was not a big surprise, but was not expected. We found that just like with full power loads for handguns and rifles, having a minimal powder gap behind the bullet seemed to provide the best performance.

It also seemed to increase chamber pressure, as the cases came out much cleaner than on those seated to mag length. Those seated to mag lenght were noticieably dirtier and it was clear gas was escaping through the chamber. That probably was why cycling was unreliable.

 

[shibumiseeker]

I've found the deeper seating is best in all loadings for the 300 BLK.

Did you measure to see if there was setback for the mag length rounds? This round will be especially prone to it since the neck tension relative to the the weight and size of the bullet is fairly low. With some 220gr rounds I loaded, actually seating them on the powder for a slightly compressed load gave the best performance.

I just made my first piece of brass for the 300 BLK, hope to make some more when the mini chop saw arrives

 

[esrice]

Thanks for the updates guys!

 

[Hop]

Well that's somewhat discouraging. A quick Google-fu search shows some 218 grain sub-sonic optimized bullets from The Bullet Depot -THEBULLETDEPOT - Vibrating Bullets as good performers.

Pics on Corbon's website here:
Subsonic Bullet Design

 

[jblomenberg16]

I've found the deeper seating is best in all loadings for the 300 BLK.

Did you measure to see if there was setback for the mag length rounds? This round will be especially prone to it since the neck tension relative to the the weight and size of the bullet is fairly low. With some 220gr rounds I loaded, actually seating them on the powder for a slightly compressed load gave the best performance.

I just made my first piece of brass for the 300 BLK, hope to make some more when the mini chop saw arrives

We did notice some set back on the soft point ammo. We had a few that had both cycled automatically, and also manually, that we then ejected when the range went cold. The setback wasn't quite as deep as what we were trying to seat to, but was in between. That could also add to the variation we saw in velocity and cycling.

 

[mammynun]

Site sponsor Orion Arms has 300 BLK ammo available. Red Star (made in Indiana) is $29.95 for 50 rounds. 110gr V-Max pushed by 19.5gns of H-110 yields 2300 FPS if what's printed on the box is correct. I picked up 2 boxes to try out. The headstamp on mine is all Lake City 08 with the NATO cross... nice and polished, looks like good ammo at a very competitive price.

They also have some Remington (not the UMC), but I don't recall the specifics or price.

 

[dagibson1507]

Just finished a mini dissipater build. 8" cmmg barrel with pistol gas system, kies adjustable gas block, spike upper and bolt. Runs very well so far and when my stamp finally comes in will look almost like a integrated suppressor barrel while still having a hand guard. Have to say if i did it again i would pass on the kies adjustable block. Nice because its steel instead of aluminum but the fit wasnt great. Need to drill a hole in the heat shield so I can adjust the block without removing it.

 

[esrice]

Looking forward to seeing it with a suppressor mounted!

 

[jblomenberg16]

Just finished a mini dissipater build. 8" cmmg barrel with pistol gas system, kies adjustable gas block, spike upper and bolt. Runs very well so far and when my stamp finally comes in will look almost like a integrated suppressor barrel while still having a hand guard. Have to say if i did it again i would pass on the kies adjustable block. Nice because its steel instead of aluminum but the fit wasnt great. Need to drill a hole in the heat shield so I can adjust the block without removing it.

Looks great! I'm assuming this will be a gun with a dedicated optic...whatcha thinking about putting on it?

 

[dagibson1507]

Yeah ive got a pa micro dot to put on it. I just hadnt had a chance to throw it on yet. Ive about 100 rounds threw it with no hiccups. Easily kept it on a 6" plate without really sighting it in. I did notice a little but of gas face so I'm going to try this mod Suppressed AR - and hate getting gas in the face? - Page 2 - AR15.COM and im going to try the high temp silicone mod. I can only imagine it will get worse with a suppressor. I'm holding off on a can until huntertown releases their 762kestrel, non ak version.

 

[Oppugnall]

Own a Daniel defense in 300 blackout, still haven't shot it yet too many new toys. Definitely, going to need to reload at these prices... Not as bad as the 458 socom, I'm building.. But I like the idea of round so much it's the basis of my Form 1 SBR paperwork I'm filing this week.

 

[shooter521]

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

 

[lovemywoods]

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

Very nice! I hope I get a chance to shoot it someday!

 

[esrice]

Nice!

 

[dubsac]

I have a feeling esrice is next to drink the koolaid

 

[shooter521]

I have a feeling esrice is next to drink the koolaid

.300BLKoolaid. SUCK IT.