Crimping for 9mm

[onelight]

Lee has the directions for die adjustment on the Lee sight . If your gun will shoot .355 / .356 cast bullets the carbide factory crimp works great . My 9s all will shoot .356 Hi-Tek with out leading if I keep velocities moderate.
You will just need to experiment a bit and see what your guns want. If your gun and or the load you want requires an oversized bullet if not cast hard you may need a standard taper crimp die , the bullet seating die will apply a standard taper crimp . Assuming of course it is a standard 4 die 9mm set.

[WheelgunConvert]

It keeps the fixed size ring higher on the case where it is smaller. Even if the ring is straight walled the geometry applies. Think of it as additional tolerance higher on the case.

YMMV- it works for me.

[1006]

The Lee Carbide Factory Crimp Dies that I have were purchased when they first came onto the market. So, they may have changed since then. I do not know. I have had problems with the 9mm, 357, and 45 Colt/LC.

[charlie b]

I love the Lee FCD's. I use them for my 9mm, .45acp and .357. Just adjust to suit your pistol.

[tazman]

I love the Lee FCD's. I use them for my 9mm, .45acp and .357. Just adjust to suit your pistol.

I agree with charlie b. I use them for all my handgun cartridges and have no issues like others have talked about.

[fredj338]

I use FCD on every handgun I reload for. What I did for loading lead is have a FCD I knocked the ring out of so the case enters the FCD with no interference with over sized flat base bullets so the ring doesn’t swage the bullet. I like them for the simple fact of being able to adjust so much easier.
Am I a hack I don’t know but it works for me.

Then you really no longer have a FCD.

[David2011]

Gradually add more and more taper. Note that even an excessive crimp will barely keep the bullet from easily plopping out with a light blow from a kinetic hammer. Typically the bullet can be spun around by hand. The taper crimp die just doesn't do much for bullet pull. It can make a mechanical step to prevent setback, but that is a different mechanical process than creating bullet pull.

I’ve shot autoloaders in competition since 2006, at least 100,000 rounds. All rounds were taper crimped and were held quite tightly. Three whacks to pull a boolit.


In general, crimping has several functions. It prevents setback. It delays boolit movement until some pressure is built, preventing the primer from dislodging the boolit and increasing powder burn consistency. It prevents the boolit from moving outward. It assures that the round will chamber correctly as the case headspaces on the mouth. If oversize, the case may not seat against the forward end of the chamber. If undersize, it can go too deep. At that point the boolit has been swaged undersize.

There is only one way to determine correct taper crimp. That is to measure it with calipers. A micrometer may measure a burr on the case mouth so I measure just behind the edge of the mouth. Specs are in the reloading manuals. Anything else is just guessing.

[Taterhead]

I’ve shot autoloaders in competition since 2006, at least 100,000 rounds. All rounds were taper crimped and were held quite tightly. Three whacks to pull a boolit.

I don't talk about my round counts on public forums (just a personal thing), but it is a statistically significant number. I've been shooting and loading much longer than I've been a member of this forum. Both in range time, and on a timer. A bullet seated into a case with the correct inside diameter will take a similar force to dislodge the bullet due to the interference fit. That is neck tension at work. Same thing will happen if the bullet is pulled before crimping.

In general, crimping has several functions. It prevents setback.

If crimping enough to create a mechanical step in the bullet, then yes. But I argue that a mechanical step in a plated or coated cast bullet is too far. But that is probably another discussion altogether.

It delays boolit movement until some pressure is built, preventing the primer from dislodging the boolit and increasing powder burn consistency. It prevents the boolit from moving outward.

Wholeheartedly agree with that if talking about roll crimps, but taper crimps have minimal affect on bullet bull. The easy experiment that I described above will isolate the effects of the taper crimp and will show that it does almost nothing for bullet pull. It's all about neck tension. If I can apply a "firm" taper crimp and still spin the bullet by hand, then the crimp isn't doing much for the retention of a bullet. Furthermore, as stated earlier, the bullet will pop right out of the case, even after applying a taper crimp. Light, medium, firm. Doesn't matter. Brass springs back more than lead and copper. Squeeze the case mouth firmly, the lead swages, and the brass springs back. Unlike a roll crimp into a cannelure or crimp groove, there is minimal mechanical "grip" from a taper crimp. Otherwise a taper crimp would be sufficient to prevent bullets from creeping in our revolver loads.

It assures that the round will chamber correctly as the case headspaces on the mouth. If oversize, the case may not seat against the forward end of the chamber. If undersize, it can go too deep. At that point the boolit has been swaged undersize.

Agreed. Exactly.

There is only one way to determine correct taper crimp. That is to measure it with calipers. A micrometer may measure a burr on the case mouth so I measure just behind the edge of the mouth. Specs are in the reloading manuals. Anything else is just guessing.

I find of dimensions in manuals for case mouth ODs, but these are without crimps. Easy to deduce a crimp diameter from those nominal drawings, however. I don't believe that there is a SAAMI standard for taper crimp, but I could be wrong. Regardless, the outside diameter will necessarily increase if adding diameter with cast bullets, rendering the drawings a bit moot.

Tough to measure with calipers or micrometers. Subjectively, if it doesn't engrave the bullet with the case mouth and plunks into the gauge/chamber, that is a good taper crimp. Of course different makes of brass and different case lengths all impact the actual crimp applied (as you know). So we're looking for about an average that will work across the spectrum of mixed brass most of us use.