RCBS dies- Roll crimp or taper?

[hawaii five-0]

I'm looking into getting some dies to reload .38 special with cast projo's. I see I can get dies with a "roll" crimp, or taper. Which one do I want, and why? Thanks

[Outpost75]

Roll crimp ammunition to be used in revolvers, where bullets may either be dislodged by recoil inertia, drawing them out to lock up the cylinder,
and also for rounds to be used in repeating rifles having tubular magazines where rounds are held in the magazine under compression.

Taper crimp for all semi-autos which headspace upon the case mouth.

[Doc_Stihl]

For a 38 Special with cast, a roll crimp is the way to go.
The only reason I could think of to use a taper for a 38 would only be if you were plan on shooting swaged dry lube style wadcutters or plated bullets.

[snuffy]

I'm looking into getting some dies to reload .38 special with cast projo's. I see I can get dies with a "roll" crimp, or taper. Which one do I want, and why? Thanks

What's a "projo's"???¿¿¿:kidding:

Uh-huh, I know it's short for PROJECTILE. Just call it a bullet, since you're on cast boolits website call it a boolit!

Roll crimp in revolvers with bullets/boolits with a cannelure or crimp groove, taper crimp for all straight walled semi auto. A taper crimp for a 38 special would only be used for a plated bullet A roll crimp on a plated bullet could cut the plating.

[462]

What does your reloading manual recommend?

What's a "projo's"???¿¿¿

Is it the same thing as a "head" and a "pill".

[gray wolf]

This is a very basic question, A quick scan of any load book would have the answer.
No offense meant but a little reading would have got you to the right place.

[varmint243]

I use and prefer a taper crimp die for my 38 loads.
I don't actually crimp them I just push the case wall back to straight so they chamber nicely.
The taper crimp dies do this well and is are less finicky than a roll crimp die because of case length variations.
I shoot a light target load with 4.0 grains of fast powder and two different bullets, a 170gr SWC for steel and a 148gr WC for paper.
If you have room in your press use the crimp die at a separate station.
Follow manufacturers data recommendations.
YMMV

[BruceB]

Use the roll crimp.

Beside the thousands of .38/.357 rounds that have been fired in our revolvers, over 140,000 cast wadcutters have gone through our .38 semi-auto target pistols. Every single round had a roll crimp, although it was a very modest roll crimp in the target guns.

The 35863 wadcutter bullet I load has a very slight bevel on both ends, and that suffices for the roll crimp without the displacement of any metal. Other designs usually incorporate a crimp groove, and that's where I apply the crimp.

I firmly believe the roll crimp, properly applied. is more secure in a revolver than the taper crimp. There's little doubt that it causes metal fatigue in case mouths sooner than will the taper crimp, but that's a price I'm willing to pay for the better security (meaning the bullet is less likely to move forward under recoil, "jumping the crimp").

[DRNurse1]

Roll crimp ammunition to be used in revolvers, where bullets may either be dislodged by recoil inertia, drawing them out to lock up the cylinder,
and also for rounds to be used in repeating rifles having tubular magazines where rounds are held in the magazine under compression.

Taper crimp for all semi-autos which headspace upon the case mouth.

"...Taper crimp for Plated bullets to prevent damage to the plating...." --Thanks Snuffy


+1 Also note the COL is critical for most semi-auto applications so the roll crimp has little boolit to grab.

There is some talk about a partial roll crimp in the case of semi autos: I use this with some success in 45ACP to increase the case pressure and thereby decrease my powder needs. It also seems to prevent swaging the boolit and having the tip pushed into the case during feeding. Basically the taper crimp die is followed by the roll crimp die set to roll 1/3 to 1/2 the case wall thickness into the boolit around the circumference of the cartridge. Just my $0.02, though.

@ Grey Wolf and 462: I looked in my books. they will tell you the 'what' easily, the 'how' sometimes, but that pesky 'why' almost never. Rather than answer this why question, I suppose I could offer to mentor or direct our 'Bub' to one. I am never sure if these folks are trolling or serious, so I usually choose the answer here in this fourm since our MODS do such a great job troll hunting.

I suppose a discourse on pressure signs and building the right cartridge for the intended use is in order as well, but it is done so well elsewhere in our forum I will defer to them.

Hawaii five-0, it would be worth your while to search the site for these things.

[DRNurse1]

BTW, Outpost 75, I think you solved a revolver issue for me before I asked the question. MANY thanks!

[gray wolf]

@
Grey Wolf and 462: I looked in my books. they will tell you the 'what' easily, the 'how' sometimes, but that pesky 'why' almost never. Rather than answer this why question, I suppose I could offer to mentor or direct our 'Bub' to one. I am never sure if these folks are trolling or serious, so I usually choose the answer here in this fourm since our MODS do such a great job troll hunting.
You made a good point there, Yes the Mods do a great job. It is better to be helpful.

[Outpost75]

BTW, Outpost 75, I think you solved a revolver issue for me before I asked the question. MANY thanks!

Nice to know I did SOMETHING right! 8-)

[Char-Gar]

Nice to know I did SOMETHING right! 8-)

I am keeping an eye on you, just waiting for you to say or do something wrong. Thus far it is a vain watch, but I will stay on the job. :-)

[monkeywrench]

Normaly the proper crimp die comes with the set. Not really any choice to make. I have never seen a revolver die set come with a taper crimp.

[Digital Dan]

Guessin' I'll be the heretic here. Been shooting a 77/44 and Super Redhawk for quite a long while with 300 grain pure lead paper patched loads that are taper crimped. They are max loads and generate about 1600 fps from the rifle according to the Chrony. They also shoot MOA at 100 yards from the same gun. My suggestion is to use what is required. Do not bother with a "taper crimp" applied by juggling a roll crimp die, the geometry is not amenable to that. Roll crimps kill the patch resulting in leading and poor accuracy. Learned that with the first loads in 1998. I have never had a malfunction due to bullet displacement in the magazine or cylinder over the course of 1500 + rounds fired.

[dragon813gt]

Normaly the proper crimp die comes with the set. Not really any choice to make. I have never seen a revolver die set come with a taper crimp.

This was my first thought. Followed by, we're on the Internet so why not perform a search for "which crimp for......." Another very basic question that worries me.

[varmint243]

The die sets do come with the proper crimp die depending on whether you prefer a taper or roll crimp

taper crimp
http://www.midwayusa.com/product/136436/rcbs-carbide-3-die-set-with-taper-crimp-38-special-357-magnum
you can choose a set with taper or roll crimp seating dies

roll crimp
http://www.midwayusa.com/product/485205/rcbs-carbide-3-die-set-38-special-357-magnum

The question is a very good question and not a simple one with a simple one size fits all answer.
After years of experience reloading I find a taper crimp die to be my preference.
This has been discussed on other forums that I read and there aren't so many pompous *ss I know it all replies.

[gray wolf]

I will speak for myself I guess, "" I am not to old to learn something ""
Sometimes it's better to keep ears open and mouth shut.

[Dale53]

A number of years ago, I did a serious investigation at our local club. We have a Ransom Rest and with the help of a number of members (all shooting light target loads in revolvers) we were able to determine to our satisfaction that when using a .38 Wadcutter, we got more accurate results using a light taper crimp die with those wadcutters (both cast and swaged). We shot many thousands of rounds with several National Class shooters.

For the record: All of my heavy cast bullet loads in revolvers use a good roll crimp.

Just a comment...
Dale53

[unique]

Taper crimp for 38 special. Just need enough taper to remove the flare which minimizes reworking brass and less chance of swaging the boolit.

[Char-Gar]

I'm looking into getting some dies to reload .38 special with cast projo's. I see I can get dies with a "roll" crimp, or taper. Which one do I want, and why? Thanks

I have some experience with hand loading the 38 Special and would buy a roll crimp die. If the bullet has a crimp groove use it and roll crimp the mouth there. I have one NEI wad utter with no crimp groove and if loading the bullet flush with the case mouth I use a roll crimp over the top edge of the bullet. This is the way factory match ammo is loaded.

I will use a taper crimp in those rare instances where I need to crimp on the bullet body where there is no crimp groove.

I am talking revolvers of course.

The question remains about how much crimp to use. That depends on the pressure of the load and recoil. I heavy bullet six gun bullet under heavy recoil, can jump the crimp and tie up the cylinder, but that is not a 38 Special issue.

On light recoil loads, just use enough crimp so your finger nail does not catch on the case mouth.

Taper crimp auto pistol rounds.

I have loaded hundreds of thousand of 38 Special rounds over the past 50 years and this stuff isn't nearly as complex as some folks make it.