The .065" port 12.5" will work well.
I have one very similar to that. I used to have my accupower 1-4 on it, but switched it out for a MRO. I wish I had a non-reflex can like a saker K or something smaller. As it is, my SPR/M4 is sitting on my 16" in a DMR type role right now, and it gets shot less because of that. Saker K, after the potential passing of the hearing protection act, would be on my short list however.
Thanks!
I thought about going up to a #52/.0635 , but decided to skip it and go to .0650. After testing the .0625, i wanted a wider range of function while keeping a relatively conservative port size.
Had I chosen to shoot 5.56 only, I could have kept the .0625, or suppressed only the original port. In the end, I think this is a happy medium for my uses.
Update: tested the .0650 port today and was a little surprised at the results. It seems between .0625 - .0650 is the threshold for perfomance window with this 12.5" barrel and chamber.
Previously (.0625)it was appropriately gassed for 5.56 only with an A5H2, but would not lock back reliably with .223 and an A5H0.
Now it will lock back an A5H4 with PPU .223 with both a standard FA carrier or an E carrier. I had hoped to tune it to an A5H0-A5H2 for .223/5.56 unsuppressed and A5H4 suppressed, but it seems the pressure difference between .223 and 5.56 is too much to tune "optimally" for both.
Oh well, I am going to keep this port and am happy with the results. I will be running the A5H4 suppressed and do some further testing as to which buffer to run unsupressed. Both A5H2 and A5H4 run reliably and the A5H4 recoil impulse feels a little better to me and would simplify operations (not having to switck buffers) , but I need to run it through its paces to see.
Last edited by dentron; 12-11-16 at 09:27.
Good update.
Sounds like it's tuned just about perfectly.
Black River Tactical
BRT OPTIMUM Hammer Forged Chrome Lined Barrels - 11.5", 12.5", 14.5", 16"
BRT EZTUNE Preset Gas Tubes - PISTOL, CAR, MID, RIFLE
BRT Bolt Carrier Groups M4A1, M16 CHROME
BRT Covert Comps 5.56, 6X, 7.62
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