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Looking for a 300AAC / Blackout barrel

28K views 65 replies 19 participants last post by  kimberkid 
#1 ·
I've seen posts where someone is going to produce barrels in different caliber's but haven't seen any actually for sale ... Of course ultimately I'd like to have the barrel & gas system in one unit ... I suppose that would be a caliber conversion, and they don't seem to exist.

Any advise appreciated!
 
#38 ·
Could you get around the shorter dwell time by expanding the gas port (possibly dramatically)?
Since we're on a piston gun, isn't it a straight shot through the block to the piston? And we're not limited by gas tube diameter, etc.

(On a tangent, how on earth is the MDR-C hoping to accomplish this? Their material says they'll offer the shorty in 300 BLK, but from the pictures it looks like the gas block is basically sitting on the muzzle.)
 
#39 ·
Not sure, I've not looked into building a 300blk based midlength port, I generally stick with pistol length. I'll look into a couple options for this. No promises that anything will work though.

With that being said, the pictures of the MDR's in your link are probably stock photo's of 5.56 or 308 rifles. They definitely have some 3d printed parts on the lower so those aren't production yet.
 
#40 ·
Had a look at the ACR gas block, and the gas port is downright cavernous.
The port in my barrel is ~0.0625, and if memory serves, the standard AR gas port is 0.0700; the gas block is a hair over 0.0900.
I almost wonder if they did that with this very problem in mind.
 
#43 ·
No that's way too long for blackout.

I didn't realize we were talking about a giant 8 foot rifle here. I thought he meant a real length, something 12.5 or down.

You do need a pistol length on a 14.5. But with only running three ways, and opening up the port you may be able to do it with carbine, but it'll likely need way more than .09.
 
#50 ·
Is Martin's gas block/piston conversion the Adams Arms piston retro fit kit? (that's what came up when I googled it)

If so, yes I had the same thought ... I ordered an AA retro piston kit and a CMMG 16" 300 BO barrel. The height of the gas block in the kit is taller than the one in the ACR so that the piston isn't perfectly parallel to the bolt carrier block and it binds where it passes through into the receiver.
 
#62 ·
Yes I build them to order. If you want one I can have one built up. Depending on what length you are wanting the prices start at 685 for a complete barrel set.
 
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