Originally Posted by
bigkracka
Would a Colt 11.5" FBI HRT unsuppressed benefit from a BRT gas tube or insert? What size would you recommend?
Where did you purchase this Colt FBI barrel? I bought one several months ago from Arms Unlimited and posted about it here....The version with the factory shaved front site post. After I installed it I noticed the gun was very overgassed kicking M193 at 1 o’clock, Fiocchi 223 at 2:30-3 and Brown Bear 55 gr at 3:30-4. This using a standard Colt H2 buffer and spring. Many have reported these GPs to be .070. Clint sent me some old bits and the GP actually measured .073.
I ended up getting one of his tubes sized at .069. Now m193 ejects at 3-3:30 and .223 at 4. Brown Bear will not eject the round. I have to try with a H1 buffer to see if it will work with the Brown Bear (I only shoot this for the local carbine classes).
The tubes definitely work as advertised. In hindsight I may have gone with .070 for this particular barrel to not worry about really weak stuff.
"A flute without holes, is not a flute. A donut without a hole, is a Danish." - Ty Webb
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