38/357 crimp question?

[mickeyblueyes]

I was looking thru RCBS equipment page and I saw both taper crimp and roll crimp seating dies.

When would you use a taper crimp on a 38/357?
I was under the belief that revolvers all got rolled.

 

[BLUEDOT37]

To taper or roll

When would you use a taper crimp on a 38/357? I was under the belief that revolvers all got rolled.

Most revolver bullets have a cannelure & take a roll crimp. Most plated & swaged lead bullets do not have a cannelure & would be better suited to taper crimp. (Taper crimps in high recoil revolvers (light weight gun & hot loads) usually don't hold well but this wouldn't likely apply to any plated or swaged lead loads I can think of, just a FYI.)

That said, I've never owned a taper crimp for 38/357. You can usually get by with minimal adjustment on the roll crimp die & just remove any flare/bellmouth. I do have a taper crimp die for 45 Colt for times when I want to use 45 ACP bullets (no cannelure) in them.

 

[MichiganScott]

Taper crimp works well for high volume shooters that may use brass from different manufacturers and lots when reloading with a progressive press.

 

[Malpaso]

I have all RCBS dies, but I use the Lee Factory Crimp Die for .38spl/.357mag and .44spl/.44mag

 

[rockquarry]

Case length uniformity is not as critical a factor when using a taper crimp die as it is with a roll crimp die, but, in many instances either type will work well if done right.

Degree of crimp is a relative term that doesn't have the same meaning to everyone. Accuracy can be destroyed with either crimp type by applying too much crimp causing distortion to the bullet. Crimp just enough so that the bullet does not jump the crimp under recoil. Some contend that magnum cartridges must be heavily crimped to "insure proper ignition". Hard to say exactly what a heavy crimp is, but the "just enough" rule will cover this.

Having done some accuracy comparisons with both crimp types using the .38 Special cartridge and cast bullets, my results have been inconclusive. Both have worked fine. Perhaps others who have done extensive testing can provide something more definitive.

Going with conventional wisdom rather than fact, I roll crimp .357 magnum loads. It may be true the roll crimp is stronger than the taper crimp, but I can't attest to that. Perhaps others can.

 

[mickeyblueyes]

Thanks guys, I am fairly new to the reloading scene about two years, and I face this same question in a different caliber, I have a .625 in 45 acp and aSig in .45 acp. Thru experience I have witnessed the taper crimps loosen in the 625 , so the get rolled. I am now judging whether the roll crimp effects the accuracy of the Sig. Not so far it seems.

 

[moxie]

Taper crimp is suitable for .38 spl./.357 and .44spl/.44 mag when using light loads with cast bullets that don't exhibit bullet jump. There's no need for a roll crimp if there's no bullet jump.

With the 625 in .45acp I've loaded some very hot loads with 230 fmj and taper crimp, same as with an auto, and had no bullet jump. You have to test and see what's happening with your load in your gun.

Very light revolvers with alloy frames are very prone to bullet jump (it's just physics), so proceed accordingly.

 

[Vulcan Bob]

In light to medium .38 Special loads I use the taper crimp, seem to get longer case life with the taper before case mouth splits. In the .357 Mag, I use a medium to heavy roll crimp depending on the load.

 

[mickeyblueyes]

You know it little tid bits of information like this ,that save a whole lot in the long run. Thanks to all those who have posted.

 

[Harley Fan]

You know it little tid bits of information like this ,that save a whole lot in the long run. Thanks to all those who have posted.

Well, I thank you, mickeyblueyes, for posting this thread, as I had a slightly different question and it would have fit right here, but I think it's been answered.

I'm a beginning re-loader, just 1,300 rounds or so into it. I guess that I've been exposed to both crimp styles, as I began re-loading .38 Sp with a Lee loader, loading with a 125 gr. plated bullet. I had occasion to pull off a few bullets early in using this, to verify the strength of the taper crimp. And boy! I was pounding a death grip on these.

I'm now using a RCBS Partner press and Lee dies. I just learned from this thread that I may have had a choice in crimp styles... my Lee crimp die roll crimps. I'll also mention that my only loading requirement is .38 sp. and .357 using my own brass, and that after a pilot run of 125 gr. plated bullets, I've switched to (and am very happy with) 158 gr. lead bullets, with the cannulure groove.

I still have 30 rounds of .38 loaded with my Lee loader I just dug out for comparison to the .357 stuff I loaded the other day.

Without knowing what a light vs. heavy crimp really is, I set my crimp height to just feel a "bump" as the press closes. This is a crappy pic, but to my eye, I can see that the edge of the case has turned slightly inward, and it;s uniform.

These .357 cases are mine, shot once, and all perfectly uniform, length-wise. I'm using these with a middle-of-the-road target load, using standard primers.



Apologize for the **** pic.

Altho I've tried to do so, as a result of this thread, I'll keep a sharp eye on both my cartridge lengths, as well as a splitting condition.

 

[Nevada Ed]

I don't know about the others here but on my .357 Magnum ammo, I normally put just a medium or medium heavy crimp on my "Quality" heavy wall JHP bullets from Speer, Sierra, Hornady, Rem. etc.
The faster Lead bullets can go from a medium crimp to a "Heavy" crimp at the maximum loadings.

 

[rwsmith]

With .38 type loads....

Anything below a +P .38 can use taper or even no crimp. When you load up and get more kick start using a roll crimp. A medium roll crimp is about as much as you need, unless you are using a slow powder that needs more constriction for good burning, Then you want to use a heavy roll crimp.

In a lighter gun, the bullets will start to back out sooner because the mass of the gun doesn't help with recoil. Increase crimp accordingly.