Roll versus taper crimp, 357 Magnum

[Penforhire]

My reloading manual clearly says to roll crimp for use in revolvers. I understand the reasons. But I see there are taper crimp dies sets available for 357 Magnum/38 Spec..

Why? Are there firearms headspaced on the case mouth, maybe single-shots, that prefer taper crimping using this rimmed cartridge?

 

[Mike Irwin]

Taper crimping is perfectly adequate for light to moderate .38 and .357 loads.

It deforms the case less, which means that the cases will generally last longer, and can promote increased accuracy.

Roll crimps are really needed only if you're shooting moderate to heavy loads.

 

[MonkeyMan]

Heavy roll crimps also tend to work harden the brass and shorten case life.

 

[Thirties]

As a new loader, one of my gripes is the poor quality of most reloading manuals and books, especially the lack of fine illustrative images.

For example, I've not seen a photo of what is an adequate roll crimp, and what is over-crimped.

Would you folks mind commenting on a photo of a .38spl job I'm, working on? I'd really appreciate the feedback. I'll shoot a photo today and upload.

Thanks.

 

[P95Carry]

Most points have been satisfactorily made. IMO I'd always roll crimp ..... but that is very relative.

For a target 38 load and using as I usually do my own cast 158 swc ...... the crimp would be barely discernible ...... enough to hold bullet reliably but not doing much work hardening to case mouth.

For hotter loads then my crimp would show for sure ... actually beginning to ''bite'' into lead ....... or as often, actually curling round over first grease groove. I accept shorted case life with 357 mag because i am of opinion that good bullet retention is essential .... both to minimize bullet setting fwd thru recoil from other chamber in a revo ....... and, as important .... to add that slight and consistent ''hold'' on a bullet on top of slower burning powders, so assisting initial ignition.

Look 4ward to seeing a pic later ..... in fact if I get to it ... I'll try and post a diagram of what I describe.

 

[Mike Irwin]

Quite frankly, the amount of "adequate" crimp can vary wildly depending on the power of the load and the gun in which the round is fired.

Some years ago I loaded several hundred .38s for use in my Model 19. Not a stout load, about 4.2 grains of WW231 and a 158-gr. LSWC. I didn't crimp them, just relied on neck tension.

I had absolutely no problems with those rounds.

However, a friend went to the range with me and ended up shooting a bunch in his Model 37, a smaller and lighter gun which, because of its weight, recoiled a lot more.

In fact, it recoiled to the point where the bullets were jumping and tying up the 37.

I suspect if those loads were put into one of the new uberlight Scandium guns that the bullets in the rounds not being fired would actually go down range and hit the target. Well, maybe not...

Essentially, for any cartridge, my goal has always been to use the minimum amount of crimp necessary to hold the bullets in place in the gun in which I'm going to be shooting them.

When I'm loading some of my 1550 fps. 125-gr. .357 Mag. loads, though, they have a SUBSTANTIAL crimp because they're snappy as all get out and I'm going to be shooting them in both the Model 19 and the 28. Were I shooting them in just my 28, I wouldn't need as much crimp.

Anyway, the point remains... Crimp is relative.

 

[Thirties]

OK, here's a photo of a roll crimp on a HBWC in .38spl.

I would appreciate any comments as to the adequacy or degree of crimping here, as best as you can judge from a photo.

It is a 148 grain Hornady LHBWC seated almost flush with the case mouth, as you can see. This is just a dummy round, but I will be loading the thing with a light charge of Bullseye -- maybe 2.7 grains. Will shoot in a SW model 15 with 4" barrel.

As you can tell, I'm new to loading and still confused by bullet depth and crimping, especially when they are not fixed in granite, but up to the loader.

You see, I have no idea if the illustrated crimp is normal, tight, or loose. Nor do I know if the bullet is seated appropriately or not, and what factors affect how deeply one chooses to seat a HBWC.

Thanks.

 

[HSMITH]

For that type of load I seat the bullet down flush with the case mouth, then roll it over the edge. The best thing for you to do really is go out and get a box of them factory loaded and eye them up. The crimp you have looks very light......

 

[Thirties]

I actually thought it was tight, but had no way to know. I bought some ammo, but is is reloaded, not "factory". In that stuff, the crimp is lighter than mine. No stores here sell factory wadcutter ammo, although I see Winchester and others do make it.

Thanks very much for your input. I will make my crimps tighter and seat the bullet flush, as you say.

Does an overly tight crimp waste energy and cause a bullet to not travel as fast?

What is the effect of overly tight crimps?

 

[Jim Watson]

A WAY too tight crimp will deform the bullet and hurt accuracy.

It will not slow the bullet down. To the contrary, a little resistance to bullet launch helps the powder burn more efficiently. Which is one reason why Magnum and +P loads should be well crimped. The other being to keep recoil from pulling the bullets.

The only revolver ammo I would use a taper crimp on would be with a plated bullet that will not stand much indention or trying to use an autoloader bullet without a crimp groove. Since I don't do either, all my revolver ammo gets a roll crimp. Also .38 flush wadcutters for my M52. It needs the little bit of radius at the case mouth for good feeding; a taper crimped wadcutter will occasionally stub out against the bottom of the feed ramp.

Furthermore, if your bullet has a proper crimp groove, you can seat and crimp in one step; no need to do separately as required for a good taper crimp on a smooth bullet. Not a problem in a progressive, but a help in single stage.

 

[Bill Adair]

I use a taper crimp on any bullets without a crimp groove, when used in rimmed revolver cartridges.

Plated bullets, such as Rainier, West Coast, and Montana Gold, have no crimp groove, and being made of very soft lead, are easily deformed.

The Lyman reloading manual for Pistols & Revolvers has a good illustration for roll and taper crimping.

Bill

 

[P95Carry]

Thirties ......... I'd say myself, that your crimp could well be about right. It is well discernible and I'd imagine gives some ''bite'' on the bullet.

Yes you can seat that WC right down and light crimp over the top ... have done that myself - and also ..... in past using cast WC's with grease grooves, actually crimped lightly into the top grease groove ....... whatever you choose which works .. stick to it for consistency.

The mention about roll crimp over top of WC does indeed confer benefits for feeding when that is an issue.

Still haven't done the diagram I referred to .. sorry, been a tad busy. But I think the info here has pretty much given you some food for thought.

Just shot a quick digi pic of a 357 homeload .. as mentioned before ..... 158 Lyman cast swc with gascheck ..... the crimp is well discernible tho not IMO excessive. Quite enough tho for me to give good bullet retention and ''grip'' for initial ignition ..... works for me. A 38 taget load would have noticeably less but still just visible.

My 44 mags show a tad more than this .... and meant to say ... To get max uniformity I use a Lee ''factory crimp'' die ...... another stage but ... seems worth it.

 

[Standing Wolf]

Hello, Thirties!

Your round looks fine to my eye, although nothing beats a side by side comparison.

I've found the less I crimp and bell, the longer cartridge cases last, and it doesn't matter whether a wadcutter is seated deeply, shallowly, or somewhere in between: as long as all your wadcutters are seated to the same depth, all will be well. I once pushed a batch of fifty all the way into the cases just to see what would happen. They shot just fine.

 

[Thirties]

Thank you all for your info from which I take away the message that loading consistancy is the most important thing.

I plan to seat my wadcutters flush and crimp over the top. Then I'll start to work on observing accuracy in my loads (after I build that shooting bench). So far, I've just been working on the mechanics and technique of loading, and observing chronograph data.

As most of you already know, this handloading stuff is really interesting and adds a lot to the enjoyment of shooting (as if anything needed to be added).

 

[Quantrill]

Another reason for taper crimp dies for a .38spec. is that the caliber is chambered in 2 semi-auto pistols that I am aware of, the S&W model 52 and for a short while, the Colt Gold Cup. Quantrill

 

[Watchman]

I personally dont use anything but taper crimp dies and I've not had one single problem with them. I use them for everything from light target loads to heavily loaded .44 magnums.

A taper crimp is much better for an automatic such as a 9mm or a .45.

If your case lenth is not exactly the same, a roll crimp will roll some looser than others and some tighter depending on case lenth. With a taper crimp the overall lenth is not near as critical, which is a plus if you are using a proggressive setup.


I was very critical of using taper crimps when they first came out.

If you doubt the ability of a taper crimp to hold a bullet in the case, try pulling one with a kinetic bullet puller. You'll find that it is usauly more difficult to extract the bullet than it is with a rolled crimp.

 

[Thirties]

" If you doubt the ability of a taper crimp to hold a bullet in the case, try pulling one with a kinetic bullet puller. You'll find that it is usauly more difficult to extract the bullet than it is with a rolled crimp."

Watchman, I know what you mean. In fact, I wonder how one judges whether a taper crimp is enough or too much?

 

[Volpe]

Well in my case I have found that a light crimp is better for light loads in a revolver. When stokeing it up I definately use a heavy crimp. I also use the lee crimper. All roll crimps for my revolvers. For autos I use a taper crimp and sometimes no crimp depending on how tight they seat in the case. An auto headspaces on the neck of the case as I'm sure you all know. In my experience I have found that a heavy crimp (revolver) on a light load sometimes dosnt even open the crimp all the way. This tells me that 1=I'm overworking the case for no gain and 2=Maybe this would have some effect on the burn rate of the powder wich would'nt contribute to overall accuracy....