Quote:
Originally Posted by Friggin Idiot
I built an SBR lower out of Spikes & LaRue parts. One upper is CMMG's RDB system with the MeanMag conversion for regular P-mags. No booster required so I put a 3-lug on it. Makes it easier to swap between the CMMG upper and the Black Rifle Arms 300BLK piston upper. Can is Rugged Obsidian45 with 9mm end cap.
X-treme Bullets 124gr FP on top of 4.0-4.2gr Win AutoComp. Velocities from 8" barrel are 860-980fps for the range. I'm not picky about the exact velocity since staying subsonic. 4.3gr is still subsonic, but definitely louder than 4.2 or less even with the can.
I was worried about using such a light bullet as a subsonic, but a buddy of mine says the 124's tend to work best. He's had lots of feeding & cycling issues trying to get a load for his 147's. Somewhere I have a bunch of 161's yet to play with because I can't find any data for anything close to that heavy.
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i hear that CMMG system is pretty good. it wouldnt surprise me if that type of design will be the future and common blowback we see everywhere will eventually be phased out. dont get me wrong, i freaking love my blowback ar9 and how soft it shoots, but hoooooooly crap does it get dirty. it doesnt help that im not the best with my cleaning regiment either. does your CMMG get dirty pretty quickly?
macon armory out of Georgia makes DI 45 upper kits with the same style BCG used in the CMMG system (the big difference being this is DI and the CMMG kit is a radial delayed blowback). so we will definitely be seeing more refined PCC bolt and gas systems and time goes on. isnt SHOT show next week? hell we may even see something then.
i have heard great things about the endo mags, although i like my PCC lowers to be glock fed as that is what i primarily shoot for my sidearm.
as for subsonic 9mm, the standard grain weight is usually always 147gr although i have seen some 124gr sub loads. i know subs can be finicky at times, so you just have to find out what works with you. you also have an 8" barrel, which will add a little velocity as most 9mm stuff isnt longer than 5" or 5.5". im sure if you google it, you can find 160/161 load data. its not too far off of 147 gr, so the powder charge will be less, but not by a whole lot.
