I have the BCA uppers. these are over gassed. H3 buffer slowed the bolt down as demonstrated by angle of shell ejection changing from about 1 0'Clock to more to the side and behind me. Gives follow more time to position the next round for feeding. No more double feeds with certain mags.
The extended firing pin is a must. Likely the extra power brownell hammer spring is not. One lower has it and the other has a larue trigger. So far both lowers work. I rather the gun be over gassed than under gassed. I can deal with an over gassed gun easier than an undergassed gun. An adjustable port is the better solution. Larger gas port and heavy H3 buffer likely results in more perceived unpleasant recoil. For a fighting gun I want full strength buffer springs. The heavier H3 while slowing down the bolt, likely removes stress from it too since the period for unlocking is longer allowing residual pressure to decline. The 7.62x39 bolt has a reputation of being less durable than the 5.56 bolt. There is more metal on the 5.56 bolt and the tapered 7.62x39 cartridge is said to put more back thrust on the bolt. 7.62x39 bolts have been improved. The bolt on any AR is a disposable item and all bolts should regularly be inspected. A properly headspacing spare should always be on hand.
Right now parts are readily available. If Trump loses the democraps might change that.
The extended firing pin is a must. Likely the extra power brownell hammer spring is not. One lower has it and the other has a larue trigger. So far both lowers work. I rather the gun be over gassed than under gassed. I can deal with an over gassed gun easier than an undergassed gun. An adjustable port is the better solution. Larger gas port and heavy H3 buffer likely results in more perceived unpleasant recoil. For a fighting gun I want full strength buffer springs. The heavier H3 while slowing down the bolt, likely removes stress from it too since the period for unlocking is longer allowing residual pressure to decline. The 7.62x39 bolt has a reputation of being less durable than the 5.56 bolt. There is more metal on the 5.56 bolt and the tapered 7.62x39 cartridge is said to put more back thrust on the bolt. 7.62x39 bolts have been improved. The bolt on any AR is a disposable item and all bolts should regularly be inspected. A properly headspacing spare should always be on hand.
Right now parts are readily available. If Trump loses the democraps might change that.