Quoted:
You could retro-fit your gas-block with a metering-valved gas tube. These allow you to adjust the gas pressure applied to the bolt carrier. Fulton Armory sells them. Would let you use a modified barrel without the Counterpoise.
View Quote
Yeah, I guess. But I think a better solution would be to not drill out your gas port in the first place. [:D]
Just out of curiousity what was your experience with the Counterpoise?
View Quote
I know four people who bought them back in 2000 and got a chance to try it myself. It did absolutely nothing for semi-auto, and slowed down the cycling rate slightly in full-auto, and all of them broke in less than 100 rounds. The piece that fits in the bolt carrier is particularly weak and prone to breakage. Three of them tried to sell theirs to me after they broke. I passed.
Tom Bowers used to have a article about his (bad) experiences with the Counterpoise on his web pages, but I don't know if it's still there.