Crimbing Dies - The Firearms Forum

jpg5324 · 05-02-2012, 02:05 PM

Will someone please explain to me the difference between tapered and roll crimp.. Will a factory crimp die work for both, or do I need two separate dies?

gdmoody · 05-02-2012, 02:55 PM

Best I can explain it is that the roll crimp appears to have the mouth of the brass slightly rolled into the seated bullet, where the taper crimp kind of pushes the mouth of the brass flat up next to the bullet. Not a great explaination but I understand what I mean.

I use the Factory Crimp Die on all of my rifle cartridges and most of the handgun.

Alpo · 05-02-2012, 03:41 PM

Think of a taper-crimp die like a funnel - a cone. It starts wide, and then tapers narrower. As the shell is pushed up into the die, it goes into the taper, and the case gets squished into the side of the bullet.

This is a sketch of the inside of a rifle seating die, but a pistol die works the same, for a roll crimp.

See the two places circled in red? Notice they are curved inward? As the case is shoved up into the die, the case-mouth hits that (it's called the "crimping shoulder") and the curve forces the case-mouth to "roll" into the bullet. That would be a "roll crimp".

No, you can't do both from the same die. The two dies are built differently.

Normally a revolver cartridge and a rifle cartridge die will be made with a roll crimp, while an automatic pistol cartridge die will be made with a taper crimp.

jpg5324 · 05-02-2012, 04:07 PM

Cool....Now it all makes sence...I get it now.

Thanks Guys

JLA · 05-02-2012, 08:02 PM

Auto pistol cartridges will have a specific crimp spec. for instance proper crimp on a .45ACP is .470" at the case mouth +/- .001"

steve4102 · 05-02-2012, 08:06 PM

Quote:

Originally Posted by jpg5324

Will someone please explain to me the difference between tapered and roll crimp.. Will a factory crimp die work for both, or do I need two separate dies?

You didn't specify Rifle or Pistol. The Lee Factory Crimp die for pistol is a totally different animal than a Factory Crimp Rifle die.

LDBennett · 05-03-2012, 08:24 AM

jpg5324:

Did you read the sticky on crimping at the top of this forum page (Reloading)?

LDBennett

jpg5324 · 05-03-2012, 08:52 AM

So, if I get the Lee Factory Crimp Die for my .357, I will get the proper roll crimp. And if I get the Lee Factory Crimp Die for my 9mm, I will get the proper taper crimp??

jpg5324 · 05-03-2012, 08:55 AM

To: LDBennet
No...But I will go back and read it now......thanks

mikld · 05-03-2012, 01:11 PM

Quote:

Originally Posted by jpg5324

So, if I get the Lee Factory Crimp Die for my .357, I will get the proper roll crimp. And if I get the Lee Factory Crimp Die for my 9mm, I will get the proper taper crimp??

Prolly. .357/revolver; roll crimp. 9mm/semi-auto; taper crimp. But for me and my ammo, I have no need of the Lee FCDs for handgun ammo. I shoot lead bullets in my revolvers and a FCD swages the bullets undersize. Loaded properly, semi-auto ammo doesn't need post bullet seating resizing...

05-02-2012, 02:05 PM	#1
jpg5324 Member Join Date: Apr 2012 Location: Escalon, Ca Posts: 43	Crimbing Dies Will someone please explain to me the difference between tapered and roll crimp.. Will a factory crimp die work for both, or do I need two separate dies? -->

05-02-2012, 02:55 PM	#2
gdmoody Advanced Senior Member Join Date: Sep 2007 Location: Northeast Georgia Contributor Posts: 6,310	Re: Crimbing Dies Best I can explain it is that the roll crimp appears to have the mouth of the brass slightly rolled into the seated bullet, where the taper crimp kind of pushes the mouth of the brass flat up next to the bullet. Not a great explaination but I understand what I mean. I use the Factory Crimp Die on all of my rifle cartridges and most of the handgun. __________________ NRA Endowment Member GeorgiaCarry.Org Member Retired US Army Postal Worker Personally, I carry a gun because I'm too young to die and too old to take an ass whoopin'.....author unknown (but obviously brilliant)

05-02-2012, 03:41 PM	#3
Alpo Advanced Senior Member Join Date: Feb 2007 Location: NW Florida Posts: 8,649	Re: Crimbing Dies Think of a taper-crimp die like a funnel - a cone. It starts wide, and then tapers narrower. As the shell is pushed up into the die, it goes into the taper, and the case gets squished into the side of the bullet. This is a sketch of the inside of a rifle seating die, but a pistol die works the same, for a roll crimp. See the two places circled in red? Notice they are curved inward? As the case is shoved up into the die, the case-mouth hits that (it's called the "crimping shoulder") and the curve forces the case-mouth to "roll" into the bullet. That would be a "roll crimp". No, you can't do both from the same die. The two dies are built differently. Normally a revolver cartridge and a rifle cartridge die will be made with a roll crimp, while an automatic pistol cartridge die will be made with a taper crimp. __________________ Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297 I always take precautions. Beware the Evil Bullet Fairies.

05-02-2012, 04:07 PM	#4
jpg5324 Member Join Date: Apr 2012 Location: Escalon, Ca Posts: 43	Re: Crimbing Dies Cool....Now it all makes sence...I get it now. Thanks Guys

05-02-2012, 08:02 PM	#5
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,305	Re: Crimbing Dies Auto pistol cartridges will have a specific crimp spec. for instance proper crimp on a .45ACP is .470" at the case mouth +/- .001" __________________ It takes 43 muscles to frown, 17 to smile, and 3 for proper trigger squeeze. The latest caliber or gear is no substitute for experience and skill. Rifles and cartridges don't make hits -- shooters do. Fact of life: After Monday and Tuesday, even the calendar says WTF!

05-03-2012, 08:24 AM	#7
LDBennett Advanced Senior Member Join Date: Dec 2003 Location: Hesperia, CA Posts: 5,710	Re: Crimbing Dies jpg5324: Did you read the sticky on crimping at the top of this forum page (Reloading)? LDBennett

05-03-2012, 08:52 AM	#8
jpg5324 Member Join Date: Apr 2012 Location: Escalon, Ca Posts: 43	Re: Crimbing Dies So, if I get the Lee Factory Crimp Die for my .357, I will get the proper roll crimp. And if I get the Lee Factory Crimp Die for my 9mm, I will get the proper taper crimp??

05-03-2012, 08:55 AM	#9
jpg5324 Member Join Date: Apr 2012 Location: Escalon, Ca Posts: 43	Re: Crimbing Dies To: LDBennet No...But I will go back and read it now......thanks Last edited by jpg5324; 05-03-2012 at 08:57 AM..