As it has been said: people do use the Lee FCD for many different bullets, cast lead and copper jacketed-- revolver and semi auto.
I believe in having an understanding as to why we do certain things while reloading, rather
than just pulling the handle on a loading press. Crimping is a different animal for a revolver and serves a little different purpose. The revolver with it's rimmed case uses a roll crimp, it reduces the case mouth in a circular fashion allowing the case mouth to dig into a crimping groove. This helps to hold the bullet in place during recoil and helps with proper ignition of the powder in certain loads. Yes some people do not crimp rimmed cases when shot as single shot, as long as the case mouth flare or bell has been removed and the round will chamber--and bullet set back is not an issue. The 45 uses a taper crimp, it reduces the case mouth vertically not just circumferentially.
The 45 acp and other non rimmed cases head space on the case mouth, the little ledge you see at the end of the chamber. There is much debate as to the 45ACP in relation to it's head spacing off the extractor, or the case mouth. Why? because 45 cases get smaller as they are shot and reloaded.
If you remove the barrel from your 45 and drop a case into it, does the case head come to rest even with the back of the barrel hood? proly not, more than likely it will sink below the barrel hood.. What most people find is that the exposed lead at the end of the case is what is stopping the case in conjunction with the extractor. loaded rounds should drop into you barrel easily and come to rest at the end of the barrel hood.
Pages of debate have been written about this one subject alone. Other than what I have said I will leave that alone, and try to stay on subject.
Why do we crimp a 45 ACP ? IS IT TO INCREASE BULLET HOLD? No it does not increase bullet hold with lead bullets.
Does it help eliminate bullet set back with lead bullets? sorry it does not.
Why? OK lets understand how taper crimp works. It squeezes the case mouth and reduces it's size.
At the same time it must reduce the lead bullet in size, how can it not. The brass has what we call spring back--it will pop back out a little--the lead bullet will not. So is that a big deal? yes it can be.
Why? because I have slugged my barrel and found the bore diameter to be --lets say .451 and to have a proper seal in the barrel, reduce leading and aid in accuracy I have sized my bullets to .452--
.001 over bore size. if I over taper crimp I could reduce the lead bullet back to .451 or .4515 and have problems with leading and accuracy.
The lead bullet stays in the case because of friction
( the case is smaller inside than the bullet is outside)
So why mess with the taper crimp if it can be so bad for the bullet and barrel fit?
In order to place your bullet into the case and not strip lead from it when seating, we bell or flare the case mouth for lead bullet. After seating we must remove the flare in order for the bullet to chamber.
This is why we taper crimp, to remove the flare or bell from the end of the case mouth
A reduction at the case mouth to .469--.471 will most times be fine ,and the case should chamber.
Naturally custom barrels with tight chambers may require a different approach.
Any more taper crimping should not be needed, if it is I would look at for other reasons why.
NOW for your question about the Lee FCD. It uses a small Carbide ring at the bottom of the die to post size the whole case and remove any anomaly's in the case walls, while taper crimping the case mouth. This is supposed to allow for the case to chamber in any pistol.
While it does this it also squeezes the brass and the lead bullet. the Brass springs back and the lead bullet does not. So now our properly sized .452 lead bullet is no longer .452 it could be .450--.451 or .4515. This could reduce bullet hold, cause leading and degrade accuracy.
I would try my lead bullet loads with out the FCD and see how they function. Just crimp enough to remove the flare or case mouth bell with a little pressure on the press handle. you should not see an actual line vertically from the taper crimp. You can even set you die up to do the seating and crimping in two steps. I do it in one step.
So now you know more about crimping a 45 than you ever hoped to.
I hope I have not bored you with all my mouthy ness. I get that way, but Hey why shouldn't you know Eh.
Gw.
