Re: Lee factory crimp for M1 Garand
My little brother, who shoots competitive high-power rifle (M1A, 7.62 NATO), introduced me to the FCD. The man who told him about it shoots on the Air Force rifle team.
A taper-crimp die has a slightly funnel shape to it. As you raise the shell in the die, it keeps getting pushed into a thinner (tighter) and thinner area, which squeezes the bullet/casemouth together tighter and tighter. The Lee FCD, for bottleneck cases, has a movable bottom, and fingers that come out from the side of the die. When the shellholder pushes on the movable bottom, this forces the fingers to come straight out from the sides of the die. The finger ends curved, so that when they come together in the middle of the die, they form a circle. Your bulletnose/casemouth is sticking up through the circle. The fingers squeeze, all at the same time, all with the same force, a crimp into your cartridge. If you screw the die in a little farther, the shellholder will be pushing on the bottom a little more, which makes the fingers squeeze harder - more crimp. Back the die out a little, the shellholder pushes less, the fingers squeeze less - less crimp.
With a taper-crimp die, since you are pushing your case up into the die, if you have it set too deep, while attempting to push the case all the way up, you reach a point where the case won't go up any higher. If you keep pushing past this point, something has to give. Either your steel press, your steel die, or your brass case. So, your brass case gives, the bullet gets pushed back a little into the case, which causes the shoulder of the case to bulge. Now the round won't fit in your gun. This cannot happen with the FCD, since you are not putting any downward pressure on the case at all. All pressure is coming from the side.
Yes, the Lee die will work with bullets without a cannelure.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.
Last edited by Alpo; 05-11-2009 at 09:46 AM..