Who's built a 300 BLK on the AR-15 platform? I'm looking at building and am studying barrel lengths/ gas-tube lengths/ buffer springs/etc. Would appreciate hearing from anyone who has direct personal experience shooting both supers and subs. Obviously no need to talk about suppressors and back-pressure cause we're not getting them and we can ignore that factor.
300 AAC BLK build
- Thread starter wood hog
- Start date
thegrandpoohbah
CGN frequent flyer
- Location
- Terrace, BC
I'm curious too. Have a spare 9" handguard right now and was thinking a 7.5" 300 BLK would be a fun range toy.
Pistol length gas system.
Standard carbine buffer.
Standard carbine spring.
Not all factory sub loads will cycle the action so don't think it's a problem with the rifle before you try different ammo.
If you're handloading be sure you use an appropriate powder similar to A1680 for your sub loads or you'll have problems. You can't just use whatever is listed in the book for all loads, some of the published data is only good for bolt actions.
I've been shooting and loading for 300BLK for a few years now and have gone through some of the frustrations learning through trial and error.
I still haven't tried 4227 or CFEBLK yet even though I have both powders on hand. Just haven't gotten around to it yet. They're both supposed to be good powders in the 300BLK. My go to powders are H110, Lil'Gun, and A1680.
Standard carbine buffer.
Standard carbine spring.
Not all factory sub loads will cycle the action so don't think it's a problem with the rifle before you try different ammo.
If you're handloading be sure you use an appropriate powder similar to A1680 for your sub loads or you'll have problems. You can't just use whatever is listed in the book for all loads, some of the published data is only good for bolt actions.
I've been shooting and loading for 300BLK for a few years now and have gone through some of the frustrations learning through trial and error.
I still haven't tried 4227 or CFEBLK yet even though I have both powders on hand. Just haven't gotten around to it yet. They're both supposed to be good powders in the 300BLK. My go to powders are H110, Lil'Gun, and A1680.
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thegrandpoohbah
CGN frequent flyer
- Location
- Terrace, BC
Carbine length will work in some rifles depending on barrel length but pistol length is better in most rifles.
It's not really a concern unless you're having the barrel made because the barrel manufacturer makes it whichever length they find to be the most reliable, you won't find there is a choice when buying your barrel.
If you want to run subsonic pistol length works more reliably in a DI rifle.
When I had my non restricted 300BLK barrel made for my ACR I built it with a carbine length system so I had enough room for the piston system and because there was still a lot of barrel left past the gas port so it has enough gas to operate the system.
When I had my 12 inch AR barrel made it was pistol length and it cycled super and sub well.
Yes, the whole concept behind the development of the 300BLK was to be able to simply swap barrel and gas system and go. A second complete upper is of course much more convenient but it was designed to be a very simple swap from 5.56 over to 300BLK.
Give the guys at Tier One Armoury in Edmonton a call, they'll order whatever you want if they don't have it in stock.
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thegrandpoohbah
CGN frequent flyer
- Location
- Terrace, BC
They are out of stock. I already emailed them and they are expecting more in 8 weeks. I am running a 10.3" BA Premium series barrel in .223 Wylde and very happy with it so far, especially for the price.
