Since today is Saturday and
Lee is closed for the weekend, I thought I’d ask my question here…

Can a FCD be used for a shorter bottle neck cartridge than it’s designed for?

Specifically… 9.3x62 FCD be used to crimp a 9.3x57

The top of the ram has to contact the bottom of the collet to force them up into the taper of the die body to close the collets around the case mouth.


I don't know if the shorter case will allow the case mouth to get high enough in the collets to compress the case mouth.

You might be able to screw the die in deeper but it may squeeze the case mouth too much.

I'd say take an old 57mm case and keep adjusting the die down until it works or until the collets close down 100%.

There's a lot of adjustment room, I just don't know how much it will take.

Frank,

Thanks for the info. I’m new to FCD dies as I just got one in the mail today.

Why would you want to crimp the case? Is the rifle shooting too accurately for your taste?

If your neck tension is proper then those bullets aren't going to move around, even under recoil. Crimping is for autoloaders; some truly heavy calibers like .458's can suffer from displacement of the bullets in the magazine due to recoil, usually if fired multiple times while rounds are in the magazine, so a preventative crimp may be useful.

True. FCD? Never owned one, nor needed one.
Call me.

You can crimp a case longer but not shorter. The collet part that projects from the bottom of the die is a specific length to control where the crimp is placed. You would have to machine off your collet to the right length. For longer cases, you just need to fab a spacer to place the case at the right spot.

Lee FCD dies are only forgiving of slight differences in case length i.e. differences in length of new and fired cases, but cannot accommodate materially different case lengths such as a 63mm case and a 57mm case which is approximately a 1/4" difference.

The shell holder hitting the collet face protruding from the base of the die produces the crimp so materially shorter or longer cases will have the mouth well out of position in the die to be given a crimp.

quote:

Originally posted by Stonecreek:
Why would you want to crimp the case? Is the rifle shooting too accurately for your taste?

If your neck tension is proper then those bullets aren't going to move around, even under recoil. Crimping is for autoloaders; some truly heavy calibers like .458's can suffer from displacement of the bullets in the magazine due to recoil, usually if fired multiple times while rounds are in the magazine, so a preventative crimp may be useful.

Some rifle/loads benefit from the crimp. I did an experiment many years ago shooting identical loads with and without the crimp in some of my bolt action guns.

In my Model 70 375 H&H, over about a dozen different loads, there was more than a 10% improvement in average group size.

It seemed to eliminate the majority of fliers and showed much more consistent groups. There was a significant improvement of the uniformity of the groups. I used to see a bunch of loads that shot 2 bullets into a 1/2" and the third an inch away. After using the FCD I would see a more uniform 1" group.

I did the same experiment with a Ruger 7mm Mag and didn't see any significant improvement at all. Just minor groups size differences of less than a couple of percent.

My Savage 243 with a SMK load showed an improvement large enough to continue to use the FCD for it.

Groups in my MRC gun in 6.5-284 showed no significant differences in group sizes.

Both the 7 Mag and the 6.5x284 never showed a lot of fliers so that may be the reason that there were no significant differences between the crimped and non-crimped loads.

Does the FCD wear the case mouth less than ordinary crimping? Though cases lengthen and get trimmed, it seems to me that they should last longer without crimping.

Instead of rolling/bending the case mouth the FCD just squeezes the outside of the neck. It seems to work the brass less.

The factory crimp die’s claim to fame is that it supposedly resizes the whole case to factory dimensions and puts some degree of taper crimp on the case neck.

I brought one for .44-40 due to having a die set that sometimes seats the bullet off center.

They work… but I don’t buy it works the brass less.

That is inaccurate. The Factory Crimp Die only crimps a narrow band at the case mouth. It doesn't touch the case body. It uses collet fingers to press in the brass, like some factory rounds do. The bullet acts as the mandrel. The LEE Collet Die uses the same principle to size the entire case neck against a steel mandrel. It works the brass far less than pushing it into a die then pulling a sizer button back through it. Only the FLR dies affect the case body.

quote:

Originally posted by crbutler:
The factory crimp die’s claim to fame is that it supposedly resizes the whole case to factory dimensions and puts some degree of taper crimp on the case neck.

I brought one for .44-40 due to having a die set that sometimes seats the bullet off center.

They work… but I don’t buy it works the brass less.

I believe crbutler and Bobster are both right, but cr is referring to the straight wall FCD for sizing the whole body (some even with a carbide ring) and Bobster is talking about the FCD for bottle neck cases that only touches a band of the tip of the neck in three places.
Anybody is welcome to NOT use them, but I think both are awesome for the right purposes. I love them in all my heavy kicker's (rifle and handgun) and all my lever action loads. Solid crimp without much drama about case length variations. And for the straight wall cases, you can be sure it fits your chamber if you crimped with that die (it irons out any bulges, etc.).

quote:

Some rifle/loads benefit from the crimp. I did an experiment many years ago shooting identical loads with and without the crimp in some of my bolt action guns.

Of course! I forgot about all of the benchrest champions who always crimp their bullets in. Distorting the bullet is a great way to improve accuracy.

quote:

Originally posted by Stonecreek:

quote:

Some rifle/loads benefit from the crimp. I did an experiment many years ago shooting identical loads with and without the crimp in some of my bolt action guns.

Of course! I forgot about all of the benchrest champions who always crimp their bullets in. Distorting the bullet is a great way to improve accuracy.

A lot of benchrest guys jam the bullets into the lands by forcing long loaded round into the chamber. Do you think that that also distorts the bullet slightly behind the contact point with the lands?

We're talking about less than one thousandths of crimp, all you're doing is compressing the neck around the bullet. You're not roll crimping.

Many straight wall cases benefit from the FCD.
The 45-70 more than any other I have used them on.
oddly enough, the .22 hornet shows better vel and extreme spread with a FCD applied. Maybe it thinks it's straight walled.

Mr Lee has the answer here- https://support.leeprecision.net/en/knowledgebase

"Factory Crimp Dies are only interchangeable with other calibers if the bullet diameter AND the case trim length are the same, as the die crimps the last .040" of the case at the case mouth. Some cartridges are interchangeable.
7mm STW and 7mm Ultra Mag
303 Savage and 308 Winchester."