I'm a big fan of the Lee factory crimp die, but have been running into problems recently when assembling 45 Colt ammo with 360gr True Shot bullets. When I seat the bullet, I measure over all length on each round (being small batches this is no sweat), I then crimp and measure again. I am getting consistently different readings on the two measurements; it seems that the Lee crimp die, which I have adjusted for a heavy roll crimp, is seating the bullets further down into the case. Am I using the die incorrectly? I screw it into the press until it hits the ram, back it off one-half turn and then adjust the crimp stem until I get the crimp I want, am I doing something wrong? If it's the fault of the die, are there any crimp dies on the market that can provide a heavy enough crimp without altering seating depth?

Are you seating and crimping it one operation? I shoot the 41 mag and the 44 mag and find it easier to get more consistant loads by seating in one operation then crimping in another. I use the four die pistol sets from Lee. I have never had a problem using the three die sets, but find it easier to do with the four die sets.

It's not uncommon for crimping to move the bullet a little. Especially cast bullets, with all that slick lube greasing the way. Simply adjust your initial seating depth to compensate.

If crimping moves the bullet a lot (say, more than .02"), you need to check that your brass is sizing down enough. If the brand you have is thin at the mouth at all or if your brass has work-hardened from numerous reloadings, it may come up too loose inside to keep the bullet in place. Try a few pieces of new brass to get a comparison.

Nick

Am I using the die incorrectly? I screw it into the press until it hits the ram, back it off one-half turn and then adjust the crimp stem until I get the crimp I want, am I doing something wrong?

Close but not absolutely per the instructions. Follow these steps below and try a couple to see if this helps. You are adjusting the die down to the shellholder but then back away. The die is not working against the mechanical limits of your press and I would bet that is causing the problem.

I have had a large diameter cast bullet, for the given caliber, seat deeper in the crimping operation but it has been extremely consistant. For instance a .432" bullet in my 444. I adjust the bullet seating die for an overall length of 2.5" and after the crimp is applied the OAL is now 2.49", but they are all seated that .01" deeper. I just adjust my bullet seating die to give me 2.51" and after crimping it is 2.5". It is good that you are looking at OAL at the end of the crimping operation, most reloaders don't.

Factory crimp die adjustment
The amount of crimp applied will be consistent if your press has mechanical stops built into the lever linkage, and you lower the lever to the stop every time. Start with the Factory Crimp die turned into the press until it stops against the shell holder with the ram raised all the way. Lower the ram, and turn the die in one full turn. Now try crimping a case, making sure that you raise the ram (lower the lever) all the way to the stop. You will feel slight resistance at the top of the stroke, as the crimp collet is forced up into the die body.

If the crimp is not firm enough, turn the die in another 1/4 turn and try again. If you turn the die in to the point where the four slits in the collet are closed when the ram is raised all the way, you have reached the limit.