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Posted: 11/8/2009 11:24:10 AM EDT
| If a bullet has a cannalure is crimping required? |
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The corillary: "If roll crimping is required, is a cannelure needed?" is true.
It is not recommeneded to roll crimp into the body of a projectile with no cannelure. The crimp into the cannelure is an extra measure of assurance of adequate bullet to case retention. If you are convinced that your autoloader dynamics will not set forward or set back the projectile in the case, when seated without a crimp then crimping is not necessary. For reference, the M193 MilSpec calls for 35 lbs. or better retention force, and the M855 MilSpec calls for 45 lbs or better retention force. |
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FYI........taken from the SPEER web site - FAQ.........
Q. The rifle bullet I'm loading has a crimp groove, but the cartridge length recommended puts the groove out of the case. Should I change the seating length to make the crimp groove line up. A. No. Not all rifle cartridges require crimping. The groove on the bullet is positioned for those that need the crimp. If the recommended seating length puts the crimp groove above or below the case mouth, we determined that crimping was not needed. Having the crimp groove above or below the case mouth has no adverse effects on accuracy or performance. –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Q. I'm reloading 30-30 ammo for my lever-action rifle. Do I need to crimp the bullets. A. Yes, crimping is mandatory for ammo to be used in any rifle with a tubular magazine. The pressure of the magazine spring and the vibration of recoil can cause the bullet to "telescope" into the case, resulting in poor feeding and increased pressure. When loading for a tubular magazine rifle, always select a bullet with a crimp groove, and one that has a flat point to prevent in-magazine firing. –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Q. I bought a reloading die set and there’s a note with the dies that says something like, “Speer does not recommend using their bullets with these dies.” What’s the deal? A. Speer never made such a broad recommendation. Speer’s recommendation is: Do not apply a crimp to any bullet that does not have a crimp groove. The die company in question markets a die to produce a “factory crimp” and recommends it be used on any bullet. Speer’s tests, and those by another bullet maker and an independent gun writer, show that crimping a bullet that doesn’t have a crimp groove degrades group size by an average of 40 percent. Other than the crimp die, we have no problem with our bullets in that firm’s dies, although our preference is for RCBS® products. We express ours thanks to the die maker for allowing us to make contact with so many new SPEER customers. Aloha, Mark |
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