07-04-2013, 06:33 AM
I'll share. Stretch the AR mags.
Before I decided on my triplets (lightweight bolt actions w same trigger pulls, LOP, scopes etc.) I was going to build a 6.5x43, a .15" longer Grendel. That would add 4 grains O2.
Simple really, mill the corners from the magwell and cut the rear section of the mags and replace them w l_l shaped section, squaring the backs and lenghtening the OAL by .15" IIRC. AR-10s, M1As and AKs dont need a big herkin bolt hold device, why does the AR? It would need a longer follower and I'm sure you could make it catch the bolt when empty but I'm a shooter/hunter so holding the bolt open isn't a priority like it would be for others.
If using the longer PRI mags you might decide to make the brass 44mm long. Working the brass is easy too. Take Prvi Partizan 7.62x39 blanks, cut em to length, neck em down and fireform. Would it be worth the trouble for 100 fps w the 123 SST? Don't know but combine that 10% additional capacity with a Superbolt and it might be worthwhile. I decided to stick w 5.56 and my -06 Lightweight BAR for my semi autos. But there's my idea, another option to consider.
Before I decided on my triplets (lightweight bolt actions w same trigger pulls, LOP, scopes etc.) I was going to build a 6.5x43, a .15" longer Grendel. That would add 4 grains O2.
Simple really, mill the corners from the magwell and cut the rear section of the mags and replace them w l_l shaped section, squaring the backs and lenghtening the OAL by .15" IIRC. AR-10s, M1As and AKs dont need a big herkin bolt hold device, why does the AR? It would need a longer follower and I'm sure you could make it catch the bolt when empty but I'm a shooter/hunter so holding the bolt open isn't a priority like it would be for others.
If using the longer PRI mags you might decide to make the brass 44mm long. Working the brass is easy too. Take Prvi Partizan 7.62x39 blanks, cut em to length, neck em down and fireform. Would it be worth the trouble for 100 fps w the 123 SST? Don't know but combine that 10% additional capacity with a Superbolt and it might be worthwhile. I decided to stick w 5.56 and my -06 Lightweight BAR for my semi autos. But there's my idea, another option to consider.