Re: 223 subsonic load
There really is no point in subsonic .223, IMO. Because if you go subsonic all you have is a slow small bullet with the power of a .22LR. Then you also risk baffle strikes. Just use Aguila .22lr "Sniper" subsonic, it shoots a 60grn bullet and will cylce a 10/22 w/ a can. Also it is so much cheaper $45 or so for 500rds.
What I plan on doing is waiting for some 300 blackout barrels to come out and build an upper for my spr, the subsonic loads will cycle and you are launching a 220grn .30 cal bullet instead of a tiny and slow .224 bullet.
