Carbine length subsonics (300blk)

[Moorvogi]

Tried a few published options, all went boom. Zero cycled the bolt. Perhaps when I replace the barrel I'll go pistol Len gas system.

For now it's rocking some 150gr fmjbt!

 

[Pinecone]

You can open the gas port.

A can would also help increase gas delivery.

 

[Marauder]

What size is your gas port in the barrel? .125 is the max size you want to open it up.
What powder are you using? 1680 & 5744 used in subs will cycle with a carbine gas system.
What buffer and bolt carrier group are you using?

 

[outrider58]

Also, what type of gas block do you have? is it adjustable?

 

[Roadhawg]

I have a 16" barrel with a pistol gas system.

 

[HT4]

Tried a few published options, all went boom. Zero cycled the bolt. Perhaps when I replace the barrel I'll go pistol Len gas system.

For now it's rocking some 150gr fmjbt!

I know that many barrel makers do not design the gas system to cycle subsonic loads unsuppressed. Opening up the gas port may be your only option for reliable operation... But beware the consequences for shooting supersonic loads suppressed.

 

[outrider58]

I know that many barrel makers do not design the gas system to cycle subsonic loads unsuppressed. Opening up the gas port may be your only option for reliable operation... But beware the consequences for shooting supersonic loads suppressed.

you will definitely need an adjustable GB for that function.

 

[rico903]

I just ordered an H&R Handi Rifle in 300 Blk Out for $222 and free shipping and no CC fees from Centerfire Guns and I won't have to deal with these problems. Comes with a threaded barrel also.

 

[HT4]

I just ordered an H&R Handi Rifle in 300 Blk Out for $222 and free shipping and no CC fees from Centerfire Guns and I won't have to deal with these problems. Comes with a threaded barrel also.

Heck of a price... Below what dealer cost was the last time I looked (a couple years ago)!


I've got one of these, but don't use it much. My 10.5" blk sbr is more fun and more accurate. The HR is a tad quieter, probably because of the minimal action noise, but the sound difference is not really noticeable that much.

you will definitely need an adjustable GB for that function.

Agreed, but what a PITA in practice. I don't really see much point in shooting subsonic unsuppressed, so I will never have to deal with this.