Used on a 14.5 Armalite and one of my BCM 11.5's in the stable.
Both guns ran 100% with all types of ammo - steel, cheap brass, 5.56 here in Montana from 0 degrees to 90ish in all seasons.
So the Armalite I will rave about, great gun for the price, but not gassed like a 6920. The BCM is circa 2018, overgassed to a harsh degree. Ironically, a circa 2019 BCM 11.5 I have seems gassed just right w/ standard parts.
Purchase was made after reading how well these were working, and I wanted to see for myself. I selected the "BRT will choose" and provided all relevant specs for that optimum choice.
Armalite system specs: Base gun, exception of VLTOR REA5 w/ A5H1.
BCM system specs: Base gun, exception of VLTOR REA5 w/ A5H2
Both carbines have newish gas rings and are PM'd respective to their round counts (BCM 4008, Armalie 1968). I was sent a .0635 for the Armalite and a .071 for the 11.5. Installed and the results:
5.56 - reliable, both.
Cheap 223 - failure to lock back, 11.5. Failure to cycle, 14.5.
Steel - failure to lock back, failure to feed, both. Stuck casings in 11.5
Quick fix check on 11.5 was to swap A5H2 w/ A5H1...change, cheap .223 lock back. No change in steel performance.
Shoot-ability went up, reliability cratered.
I reached out to BRT CS for their thoughts, after a week, was asked about my gas rings. I replied, and shared some thoughts I'll add below.
I returned to regular tubes and normal 100% reliability returned.
My conclusion, even these non-suppressor tubes are only suitable for suppressor use. In winter here, the cheap brass would have met the performance fate of the steel; the guns would have failed horribly. The opinion I've arrived at with the ammo market being what it is :
- your carbine should function with whatever ammo you can afford and find available. Gone are the days of being picky.
I have an 816A2 Piston just for this reason; it will run everything nearly on earth that is .223 or 5.56.
So, while I'm not thrilled with over-gassing, more so on the BCM 11.5, I saw the merit of it more clearly after using the BRT tubes. If you live in a harsh environment and are an intermittent suppressor user, err on the side of over-gassed over the ragged edge of reliability.
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