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Using Lee seating die to crimp autoloading cases?

zZ_d*nis said: Im relatively new to reloading pistol ammo and this question was bugging me for a while. I have a Lee carbide 3-die set for 10mm auto. I understand that there is a roll crimp feauture built into the bullet seating die. Crimp is adjusted by screwing the die in or out. I was under the impression that you can not roll crimp autoloading cartridges due to headspacing issues. Why would Lee add this feauture to their dies then?! Before i knew that the crimp was built into the die, i set up the die per instructions and the ammo produced had a slight crimp. The bullets did not have a cannelure. Should i salvage this ammo? Is it unsafe? Here's a picture of what it looks like: http://img.photobucket.com/albums/v392/zz_denis/030620101179.jpg Thanks!

tjh*ile said: Seating dies for revolver cartridges generally roll crimp and those for auto pistol rounds taper crimp. This also applies to die sets with a separate crimp die.

c*linjw said: A roll crimp is for cases that do not headspace on the mouth of the case. .38 special etc. For cases such as the 10mm , 9mm , ,45 ACP etc that headspace on the mouth of the case, the 3rd die in that set should have a taper crimp, not a roll crimp. Lee & other makers know this & build the dies accordingly. Some reloaders prefer to use a 4 dies set for these cartridges. The 3rd die just seats the bullet & the 4th die only crimps. If you double check your 10mm you should find it is a Taper crimp.

zZ_d*nis said: I've looked again at the ammo in question and it looks like a roll crimp to me. The mouth of the case looks angled like this: /l l\ Im not 100% sure how a taper crimp looks like, but shouldnt it look like a ring pressed into the case bellow the mouth? What is the advantage of crimping in a separate step? Does the "Lee factory crimp die" crimp the bullet the same as the Lee seating die?

*asyrider604 said: I've looked again at the ammo in question and it looks like a roll crimp to me. The mouth of the case looks angled like this: /l l\ Im not 100% sure how a taper crimp looks like, but shouldnt it look like a ring pressed into the case bellow the mouth? What is the advantage of crimping in a separate step? Does the "Lee factory crimp die" crimp the bullet the same as the Lee seating die? Your illustration shows you have a taper crimp. Ideally you just apply enough taper crimp to straighten the case wall and then ever so slightly (hardly noticeable) turn in the crimp die (say 1/8 turn). If you look at factory ammo, you will not see any taper at the mouth. I taper crimp my reloads to look almost like factory. Crimping in a separate step is better because you are not crimping while the bullet is being seated the last hundredths of an inch. Trying to crimp while seating may cause the case mouth to shave some bullet material. Having said that, seating/crimping has been used a long time before seating and crimping were done separately, with little or no adverse effect. The better and more correct procedure is to crimp after seating, on a separate die/station. The Lee FCD applies the crimp after the bullet is seated in a previous die, as well as final re-sizing the case with the bullet in place. This assures that your finished round will fit in all standard chambers.

Fr*edom Ventures said: I was under the impression that you can not roll crimp autoloading cartridges due to headspacing issues. Why would Lee add this feauture to their dies then?! :D Lee really didn't "add" this feature. A while back, they used to claim that crimping during bullet seating was just fine for all calibers. It was all in the adjustment of the bullet seat die. It was a gimmick that allowed them to sell the 3 die set much cheaper than a real 4 die set, and sell 3 station presses. (again, cheaper) Overwhelming proof that it didn't work from their competition (every other die manufacturer) forced them to make a proper crimp die and in turn expand presses like the turret to 4 positions. To thier credit, they went one step better and made the Factory Crimp Die, which allowed someone who screwed up with too much crimp (which in turn bulges the case) to be OK by resizing the round at the same time. A great invention.

*asyrider604 said: :D Lee really didn't "add" this feature. A while back, they used to claim that crimping during bullet seating was just fine for all calibers. It was all in the adjustment of the bullet seat die. It was a gimmick that allowed them to sell the 3 die set much cheaper than a real 4 die set, and sell 3 station presses. (again, cheaper) Overwhelming proof that it didn't work from their competition (every other die manufacturer) forced them to make a proper crimp die and in turn expand presses like the turret to 4 positions. I remember RCBS also made a 3-die set that seated and crimped in the same die. I had one and never used it because I borrowed a friend's Dillon die set and conversion kit.