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Loading Data & Reloading Procedures / Re: Question: Amount of Taper Crimp for .45 ACP Bullseye Load?
« on: December 11, 2009, 08:14:19 pm »
Taper crimping does help hold a bullet in place to some degree but its purpose is to help prevent the case mouth from catching on the hood of the barrel. Magazines that can feed empty cases are wonderful. Years ago magazine lips and followers that were set up for short, shouldered cast bullets were tougher to come by. It was common to see a hand raised at a match and a fellah holding up one hand while the other held a stopped gun with a case mouth ripped by the barrel's hood due to the cartridge leaping too high trying to enter the chamber. Had it leaped higher it would have been a stove pipe.
Quality mold makers and bullet manufacturers don't like diminishing a bullet's bearing surface any more than necessary. I haven't talked to Gil for years now, and I wonder why he still prints that. Whether revolver or semi auto square edges have a tough time passing each other they like to catch. Having the shoulder of the bullet slightly above the case mouth is another part of this same idea, to prevent catching.
The real answer if you have a properly throated gun and good magazines is to close the bell, make that black line go away and you're done. Its not a number really. Its watching the gap between the bullet and case mouth disappear. It will dwindle to a black line and then disappear. The case mouth is now laid back down against the bullet. simple as that
Quick burning propellants like Bullseye, N310, and such are not as responsive to a taper crimp as H-110 with a jacketed bullet and a roll, factory or whatever the latest flavor of strong hold that bullet against recoil or misfeeding type crimp.
Quality mold makers and bullet manufacturers don't like diminishing a bullet's bearing surface any more than necessary. I haven't talked to Gil for years now, and I wonder why he still prints that. Whether revolver or semi auto square edges have a tough time passing each other they like to catch. Having the shoulder of the bullet slightly above the case mouth is another part of this same idea, to prevent catching.
The real answer if you have a properly throated gun and good magazines is to close the bell, make that black line go away and you're done. Its not a number really. Its watching the gap between the bullet and case mouth disappear. It will dwindle to a black line and then disappear. The case mouth is now laid back down against the bullet. simple as that
Quick burning propellants like Bullseye, N310, and such are not as responsive to a taper crimp as H-110 with a jacketed bullet and a roll, factory or whatever the latest flavor of strong hold that bullet against recoil or misfeeding type crimp.