J.Baker
02-01-2020, 06:29 AM
My main problem has always been with the bolt jamming up about 1/2" before the bolt is all the way forward, requiring me to pull it back just slightly to allow the cartridge to shift a bit to allow the bolt to go fully forward. This is due to the angle of the case at that point causing the steeper shoulder to bind up on the mouth of the chamber and/or the case head to not be inline with the bolt face. It's not as prevalent of an issue on my 22-250AI (staggered feed mag), but every now and then one will hang up on me. My .250AI (centerfeed) using a standard Savage 4-rd .308 mag is a little more problematic, but livable.
My 6x47 Lapua built on an ARC Nucleus action uses AI mags and I run the 5rd Magpul's, and that's the one I had the most problems with initially. With the as-delivered feed lips the mag would hold rear of the case too long preventing it from sliding up into the CRF bolt face. By the time the case head cleared the lips the cartridge was at such an angle that it wouldn't slide up into the bolt face and would result in a jam. My solution was to trim the feed lips back with a Dremel and a small course file to allow the case head to come free sooner. Feeds fine after the mod, and I know a lot of 6.5 CM guys running the Magpul mags with a CRF action do this mod as well as that's where I got the tip from.
No clue if this mod would help on a push feed action or not.
6885
My modified 5rd Magpul mags for CRF action
The biggest issue in my opinion is that we're using magazines for cartridges they weren't specifically designed for. These different cartridges generally feed pretty well from these mag's, but not flawlessly because of the slight variations in case dimensions (shoulder angle, body taper, body length, etc). The reason for this is because it saves Savage and all the other gun makers a ton of money on R&D for developing a cartridge specific magazine. Magazines are the hardest, most costly and most time consuming part of a firearm to design and get right, so if there's an existing design that works 95% of the time they're going to go that route rather than spend the time/money to develop something new that may or may not work any better.
My 6x47 Lapua built on an ARC Nucleus action uses AI mags and I run the 5rd Magpul's, and that's the one I had the most problems with initially. With the as-delivered feed lips the mag would hold rear of the case too long preventing it from sliding up into the CRF bolt face. By the time the case head cleared the lips the cartridge was at such an angle that it wouldn't slide up into the bolt face and would result in a jam. My solution was to trim the feed lips back with a Dremel and a small course file to allow the case head to come free sooner. Feeds fine after the mod, and I know a lot of 6.5 CM guys running the Magpul mags with a CRF action do this mod as well as that's where I got the tip from.
No clue if this mod would help on a push feed action or not.
6885
My modified 5rd Magpul mags for CRF action
The biggest issue in my opinion is that we're using magazines for cartridges they weren't specifically designed for. These different cartridges generally feed pretty well from these mag's, but not flawlessly because of the slight variations in case dimensions (shoulder angle, body taper, body length, etc). The reason for this is because it saves Savage and all the other gun makers a ton of money on R&D for developing a cartridge specific magazine. Magazines are the hardest, most costly and most time consuming part of a firearm to design and get right, so if there's an existing design that works 95% of the time they're going to go that route rather than spend the time/money to develop something new that may or may not work any better.