To Crimp Or Not To crimp
Q: I've been told that bullet shoukd be crimped into a heavy recoiling cartridge like the .375 H&H and some of the new Super Magnums. My .338 Win. Mag. seems to kick like a .375 H&H, yet the 250gn Sierra bullet and Speer 250gn bullet don't have cannelures for crimping. The same goes for several other .375 bullets, including the Sierra 300gn spitzer boattail.When loading the .338 Magnum, should bullets be crimped in their cases? If not, why aren't all .338 bullets cannelured?
A: Cannelures are applied to factory-made rifle bullets for two different purposes. When loading for rifles with tubular magazines, crimping the bullet into the case mouth prevents the bullet from being pushed deeper into the case during recoil. The cannelure also serves the same role when loading for some
A few bulletmakers feel that a cannelure helps retain the lead core in its jacket during expansion, which is the second reason we see it on various bullets. When loading for my own rifles in .338 Win. Mag. and .375 Weatherby Mag., I never found it necessary to crimp case necks as long as neck tension on the bullets was sufficient to resist recoil. If the expander plug in your full-length sizing die is at least .003"smaller than bullet diameter, you shouldn't have any problem with bullets moving forward in their cases.