3 die or 4 die set

[Scottjr]

I have the Lee 4 die set for 45 acp and the 9 mm, my son and I were trying to figure the differenct between the 3 and 4 die set, he has a 3 die set for his 41mag, we want to load some ammo for his 41mag, is his 3 die set all we need to load the 41mag or do we need to get the 4th die? we are both new to reloading and can use some expert advice on this question. Thanks in advance. Scott

[brian]

fourth die is a crimp die.
not needed on most pistol rounds.
i'm doing 45acp with no crimp.
and 45colt with a crimp. depends on the bullet, iirc jacketed rounds do not need the crimp while cast lead should be crimped.
the bullet seating die will actually do a light crimp if it's set properly too.

[Farbmeister]

If you want more reliable ammo use the post sizer/crimp die. Here's the blurb:

"More importantly, the Carbide Factory Crimp Die post sizes your case assuring you that any round that passes through the die will chamber properly in your gun."

You'll be surprised how much a case will bulge when seating a bullet. The post sizer part of the 4th die takes care of that.

Lee is listing a 4 dies set for $55, you'll probably get it cheaper online. Add up all the parts from dillon or RCBS and see what $55 will get you.. not much.

[Grumpa72]

I only load for semi-autos and their is a mixed need for factory crimp dies, some say they are needed, others say no. In the Lee die set, the fourth die is a carbide factory crimp die, FCD. I use the FCD in my reloading of 9mm, .40 S&W, and .45 acp. I took my barrel off and used it as a drop in guide to see how my reloads work and they drop in smoothly after passing through the FCD.

I have no idea if they are required for a revolver.

[Scottjr]

Thanks guys for the help, I think we will load a few with the Lee 3 die set that my Son has and go to the range and check them out. Thanks again
Scott

[Flash]

Most revolver loads should have a crimp, as the recoil (and inertia acting upon remaining slugs) tend to draw the bullets forward from the cases, and in some cases, they can protrude from the chamber and stop the action.

That is the first and best reason for crimp on revolver loads.

Secondly, some powders ignite better when the bullet has a heavy crimp, thus retarding the movement of the bullet, and so maintaining a specified case-volume for the ignition to build temperature and pressure in the case according to predictable rates and levels. More so magnum loads, and Winchester data for loading magnum pistol cartridges with a Winchester powder (296 I believe it is) specifies a heavy roll crimp for just this reason.

Flash

[Lycanthrope]

For 9mm and .45 ACP you won't need a roll crimp. Most of those bullets will not have a cannelure to crimp into anyhow. In those cartridges your main enemy is setback of the bullet from repeated chamberings and that is not stopped by crimp...it's curtailed by a good sizing die. A Lee "U Die" is undersized and will eliminate it if it is an issue.

In a magnum revolver cartridge like thew .41, the rounds can walk forward due the heavier recoil and you want a bullet with a cannelure and you want a roll crimp.

I always prefer 4 die sets to crimp and seat at different stations since these are a not superior, but just A LOT easier to set up.

Lycanthereyagothrope

[RJH245]

I have the Lee 4 die sets for both 9mm and 45acp. However, I almost never use the 4th die to crimp and resize ammo. I just use the 3rd die to apply a slight tapper crimp to the round. I will, at times have a few 9mm rounds that will not drop into the chamber so if i run those rounds through the 4th die it will size them back into spec.
If I was to buy dies all over again I don't think I would have bothered with the 4 die set.

I use a RCBS 3 die set for .38 special and i have nevered missed the 4th die.


On another note, a friend of mine has a 1911 with a after market barrel that has a very tight chamber and he was loading using a RCBS 3 die set. He was having a lot of problems with rounds failing to chamber. He found that a Lee crimp die (The 4th die in the lee sets) solved the problem.

[Farbmeister]

You do not have to crimp with the 4th die... just resize. The instructions shot how to set it.

If you have it, sue it.. you'll definitely fell the case get sized as it goes into the die.

The so called 'argument' against crimping is generally fought the hardest by people who have no idea why you crimp.

The reason you crimp the bullet is to ensure uniform start pressure. Ever wonder why 99% of commercial ammo is crimped? Because it allows for more consistent performance of the powder/bullet due to start pressure being the same.

Some wackjob will always spout off about not increasing accuracy or setback or some other thing they read on the internet. But when it comes to chrony data, crimped rounds are ALWAYS better performers.

[Lycanthrope]

Magnum revolver rounds need roll crimped into a cannelure so they don't walk forward.

Lycancarefulthrope