Summary of what I have learned:
308 magazines can feed 6.5 Creedmoor, but metal mags don't always do a good job without some feed lip modification. I understand from Adam at Mile High that this is because the 6.5 case taper is a little different than 308. When pushing the bolt forward to chamber the cartridge, the cartridge tends to go straight forward instead of assuming the desired nose-up posture that will send is smoothly into the chamber.
On plastic magazines, the lips bend a little bit and allow the cartridge to feed without modifying the lips. Given the reputation AI magazines have for flawless reliability in dirty conditions, i wanted to get them to run rather than rely on plastic magazines.
There are inexpensive tools made for modifying feed lips (MDT makes one). You could also improvise, but you don't want to tear the lips up with regular pliers. I happened to have some flat-James Vise Grips that seemed made for this.
I measured the factory magazine feed lip gap at:
Rear; mid; front
0.397; 0.390; 0.337
And after a few times gently bending outward (pliers provide lots of leverage), I tried feeding again, with considerably improved bolt effort and cartridge behavior. I re-measured the feed lip gap at:
0.423; 0.413; 0.400.
I'll leave them here and run it at the range next time I go, but it feels good running 6.5 snap caps at home (snap caps are about 8 thousandths narrower than my 6.5 Prime cases, so more tweaking might be necessary.
308 magazines can feed 6.5 Creedmoor, but metal mags don't always do a good job without some feed lip modification. I understand from Adam at Mile High that this is because the 6.5 case taper is a little different than 308. When pushing the bolt forward to chamber the cartridge, the cartridge tends to go straight forward instead of assuming the desired nose-up posture that will send is smoothly into the chamber.
On plastic magazines, the lips bend a little bit and allow the cartridge to feed without modifying the lips. Given the reputation AI magazines have for flawless reliability in dirty conditions, i wanted to get them to run rather than rely on plastic magazines.
There are inexpensive tools made for modifying feed lips (MDT makes one). You could also improvise, but you don't want to tear the lips up with regular pliers. I happened to have some flat-James Vise Grips that seemed made for this.
I measured the factory magazine feed lip gap at:
Rear; mid; front
0.397; 0.390; 0.337
And after a few times gently bending outward (pliers provide lots of leverage), I tried feeding again, with considerably improved bolt effort and cartridge behavior. I re-measured the feed lip gap at:
0.423; 0.413; 0.400.
I'll leave them here and run it at the range next time I go, but it feels good running 6.5 snap caps at home (snap caps are about 8 thousandths narrower than my 6.5 Prime cases, so more tweaking might be necessary.
