6.8 SPC, roll crimp??

[ThoughtCriminal]

I'm looking at buying a 6.8SPC upper and I was looking at prices of reloading components for it, I noticed that the die sets come with a seating die that roll crimps. I was under the impression that roll crimps were exclusively for revolvers. Any help would be greatly appreciated.

[Xringshooter]

I don't know a lot about the 6.8 round but it depends on how it headspaces. If it headspaces on the shoulder a slight roll crimp is used. It helps keep the bullet in place in the magazine during recoil. Without some type of crimp on the round the bullets can move forward under recoil and could cause feeding and other problems. If a round headspaces on the rim (45acp, 9mm, 40 S&W, etc) then the bullet is held in with a taper crimp so it headspaces correctly. Check a big magnum such as a 300 Remington Ultra Mag and you will see a roll crimp to hold the bullet in place.

[BerksCountyDave]

Originally Posted by Xringshooter

I don't know a lot about the 6.8 round but it depends on how it headspaces. If it headspaces on the shoulder a slight roll crimp is used. It helps keep the bullet in place in the magazine during recoil. Without some type of crimp on the round the bullets can move forward under recoil and could cause feeding and other problems. If a round headspaces on the rim (45acp, 9mm, 40 S&W, etc) then the bullet is held in with a taper crimp so it headspaces correctly. Check a big magnum such as a 300 Remington Ultra Mag and you will see a roll crimp to hold the bullet in place.

Bingo. A roll crimp is a great idea on ammo intended for a magazine fed semi-auto rifle.