9mm AR build, go glock or go colt? reliabilty of JHPs and feeding issues?

[sigstroker]

I have both a CMMG and a PSA lower that take Colt mags.

[repoman1984]

After putting around 200 rounds through it, I can say it is definitely a far softer shooter than my gas operated .300BLK. Both are compensated the 300 is noticeably heavier with a longer barrel assembly with a higher quality vortex sight. I wish I could put it into words describing the recoil properly but, I figure this is the best way to phrase is: @ 100 yards shooting into a dusty dirt berm I can see dirt impact exactly enough to dial in my zero magnification optic in. Meanwhile the 300BLK even though its heavier and using a higher grade optic sight after firing, the jump off target visual is really difficult to see more than a puff of dust and not knowing where the bullet actually hit high or low. It really needs either a spotter or a sighting in style paper target and some binoculars to zero.