Lee factory crimp question

[usmc0811]

will the Lee factory crimp die that came with my 38/357 die set put a crimp or rolled taper on the case? I'm guessing a rolled right? Want to start loading up some 38 brass I have but wasn't sure if I needed a different die besides the ones it came with. Sorry if its a stupid question but just want to make sure I do it right.

[jmort]

Roll crimp for revolvers, and taper for pistols

[AricTheRed]

The lee FCD that came with your die set is perfect for 38/357. No other die necessary.

[usmc0811]

So the dies that came with the 38/357 set will be the one that sets a roll crimp right?

[dragon813gt]

Since it bears repeating.


Roll crimp for revolvers, and taper for pistols
I won't complicate the matter by listing all of their crimp die options.

[Super Sneaky Steve]

Lee Factory Crimp isn't a roll or a taper crimp, but it can be used in place of a roll crimp. Take a look at the die, it puts like a choke hold on the case mouth. It's a great die. I use it on my .308 brass.

Your .357 dies should be a roll crimp.

[dragon813gt]

Lee Factory Crimp isn't a roll or a taper crimp, but it can be used in place of a roll crimp. Take a look at the die, it puts like a choke hold on the case mouth. It's a great die. I use it on my .308 brass.


The rifle factory crimp, collet, die is different than their handgun factory crimp dies. The handgun dies have a carbide ring in them for post sizing cases. But to confuse matters Lee makes a collet style FCD for 357.

[texassako]

The FCD that comes in the 38/357 set puts a roll crimp on, but keep one thing in mind. If you feel the case being sized when using it, then the bullet is usually being swaged down inside the case. The carbide ring at the bottom of the pistol FCD is why some swear by it and others swear at it.

[tazman]

To further confuse things, this quote is from the Lee web site concerning their taper crimp dies.

"Lee 38SPL Taper Crimp Die, overcomes crimp problems caused by poor die design. Offers little or no advantage when used with 1986 or newer Lee Dies as the crimp angle is already a modified taper crimp."

This tells me they are no longer doing a roll crimp on their standard dies, but instead are using a "modified taper crimp". I switched my seating/crimping die over to an RCBS seating/crimping die in order to get a proper roll crimp for my 38/357 cases. It gives a much more pronounced roll crimp than the Lee crimping die.

[mongoose33]

For straight-walled cases, where you do not have a crimp groove on the boolit/bullet, the term "taper crimp" is an unfortunate term used to describe what should be nothing more than straightening out the casemouth expansion needed to insert the boolit without shaving lead from the sides as you seat it.

"Crimp," when used with "taper," is the misnomer; neck tension is what holds that boolit in place in the case, not "crimp."

A roll crimp curls the casemouth into the crimp groove in the boolit. This prevents boolit setback due to extreme recoil, which can happen in magnum rounds.

Here's the fundamental difference: a semi-auto round like 9mm headspaces on the mouth of the case, i.e., the chambered round stops at the little ledge just before the barrel throat. This is what you hear a round plunking into when you use a "plunk test" to check whether a completed round chambers correctly in such a barrel.

If you use too much taper crimp on a semi-auto round like that, it can actually jam the case into the throat which might, if your striker is long enough, cause you all sorts of Kaboom! grief as the jammed casemouth can't release the boolit upon ignition. Jammed in far enough, the striker probably won't be able to reach the primer.

Rounds like .38 special or .357 magnum can use a roll crimp because they headspace on the case rim, not the case mouth.

[kryogen]

it just works fine, why bother with the theory? use it.

[captaint]

Were it me, I would use a regular crimp (roll) die. If you don't want a heavy roll crimp, just adjust it so it just barely straightens out the case mouth and maybe a very slight roll. I hardly ever use a heavy roll crimp anymore.

[tazman]

I found that some of my 38 special loads benefited from a good roll crimp. My groups tightened and the standard deviation dropped.
Not sure exactly what the theory would be for why that happened that way. I only know it worked for me. Your mileage may vary of course.

[Love Life]

1) Seat a bullet in brass
2) Install crimp die in press just a couple turns
3) Raise ram to stop
4) Screw die down by hand until it contacts the case with seated bullet
5) Lower ram
6) Screw die in 1 turn
7) Repeat step 3
8) Repeat step 5
9) Observe case mouth
10) Repeat steps 3,5,6, and 9 until you know which crimp the die applies.

[twc1964]

+1 tazman. I also found that my groups tightened considerably when i gave my 38's a medium firm crimp. All my loads in that caliber are in the upper end area for that caliber also, maybe that has some bearing on it.

[mdi]

Were it me, I would use a regular crimp (roll) die. If you don't want a heavy roll crimp, just adjust it so it just barely straightens out the case mouth and maybe a very slight roll. I hardly ever use a heavy roll crimp anymore.
Yessir! I'd say toss the FCD and get a plain old roll crimp die. Also for a new reloader I'd recommend separating the seating operation from the crimping operation (with the seat/crimp die seat all bullets and re-adjust and crimp all cartridges)...