38 Special Crimp Measurement

Rugerrat · January 1, 2007, 09:12 PM

Can someone give me a suggested crimp measurement for 38 special loads?

Am loading Hornaday 125 grain HP-XTP bullets.

Rimrod · January 2, 2007, 12:31 AM

What do you mean by "crimp measurement"?

JJB2 · January 2, 2007, 12:56 AM

that's a new term to me too..... i just run the bullet in to the crimp groove and set it there to roll the crimp in......

LIFE IS SHORT..................

Rugerrat · January 2, 2007, 08:34 AM

My Dillon dies instructions referred to a crimp measurement that should be obtained from reloading manual. None of my manuals had any reference to this. I am assuming it is a micrometer reading at the very top edge of the case after running through the crimp die.

Rimrod · January 2, 2007, 02:41 PM

Sorry Rugerrat, Iv'e never used Dillon dies. I've also never heard of that term either and I have a lot of reloading manuals. If no Dillon users jump in try and type that sentence, plus a couple before and after, and maybe we can figure it out.

Rugerrat · January 2, 2007, 05:59 PM

On last page of die instruction sheet in the section describing adjustment for proper crimp it reads "Note:refer to a loading manual for proper crimp dimension".

kart racer · January 2, 2007, 06:36 PM

I measure a factory round and set it so it crimps in that ballpark and adjust from there.

WSM MAGNUM · January 2, 2007, 08:12 PM

Rugerrat, look in your manual and you will see the measurment of .379. That is the crimp measurement Dillon wants you to at least have when you measure with the calipers.What you are doing is getting all of the belling out of the case. Some like to have a heavier crimp. That will be up to you. But remember it increases pressure.
When you look in your reloading manual Dillon is using the cases width as a starting crimp measurement. You can put more crimp on pistol loads, but not too much. I experienced with varying the crimp on .357 Magnum loads, but most of the time I dont put any more than what the manual says.

amamnn · January 2, 2007, 09:08 PM

That "crimp dimension" will apply only to rounds you crimp into a cannelure. Not all bullets have a cannelure, and an attempt to put so heavy a crimp in those that do not will result in deformation of the bullet.

Rimrod · January 2, 2007, 09:25 PM

That would be no crimp at all!

JJB2 · January 2, 2007, 09:25 PM

amamnn is right about that and that's why i have a lee taper crimp die....... i just got done reloading another box of .38 spl homecast 150 gr. swcs.... these have a crimp groove so i roll a pretty heavy crimp into it.... i used 3.5 grs. of bulleye for a charge to use in my n frame s&w model 27...

LIFE IS SHORT...................

WSM MAGNUM · January 2, 2007, 09:27 PM

Quote:

That "crimp dimension" will apply only to rounds you crimp into a cannelure. Not all bullets have a cannelure, and an attempt to put so heavy a crimp in those that do not will result in deformation of the bullet.

No, it does not apply only to bullets with a cannelure. The measurement I gave him only removes the belling of the case. If you look in the reloading manuals at the width measurements at the neck end of the cases you can see that those measurements will apply no crimp on the bullets at all.

WSM MAGNUM · January 2, 2007, 09:29 PM

Quote:

That would be no crimp at all!

That`s correct. But, as I said before you can put more crimp if the bullet has a cannelure. But don`t go too heavy.

WSM MAGNUM · January 2, 2007, 09:33 PM

Dillons instructions are not telling you how much crimp you have to have. They are just explaining on how to adjust the die to remove the belling by using a caliper. So, the measurement of .379 is what you should at least have.

Rugerrat · January 2, 2007, 09:59 PM

Thanks for all your help! I have followed this site for a couple of years and appreciate all the experience represented here.

Rimrod · January 3, 2007, 08:45 PM

You will need more crimp than that whether your bullet has a cannelure or not. Revolver ammo needs to be crimped to keep the bullets from pulling out of the cases from recoil. If the bullet has no cannelure then it should be crimped at the ogive or at the first driving band. Starting at .379 is not safe, you need a crimp beyond "straight". If the Dillon dies have a taper crimp area before the roll crimp is started that may work for light loads but that measurement will not be in any reloading manual, that will depend on how far it taper crimps before the roll starts.

Scooter72 · January 3, 2007, 10:54 PM

When I started loading .38/.357 I thought I had enough crimp until I tried dropping a round into my cylinder. It stuck. So I adjusted my crimp a little at a time and kept checking the round with my cylinder until the round fell in freely. Never measured crimp just OAL.

skipjack · January 3, 2007, 11:40 PM

The amount of crimp is going to depend on the bullet type, cannelure or lack of, and the amount of recoil generated by the round. Heavier loads need more crimp, lighter loads need less. I generally eyeball it, and use a lee factory crimp die. I prefer a cannelure on plated or jacketed bullets. If you are loading plated bullets, don't put too much crimp on the round or the plating will be deformed upon firing.

January 1, 2007, 09:12 PM	#1
Rugerrat Member Join Date: February 20, 2005 Posts: 34	38 Special Crimp Measurement Can someone give me a suggested crimp measurement for 38 special loads? Am loading Hornaday 125 grain HP-XTP bullets.

January 2, 2007, 08:12 PM	#8
WSM MAGNUM Senior Member Join Date: September 30, 2006 Location: Maryland Posts: 750	Rugerrat, look in your manual and you will see the measurment of .379. That is the crimp measurement Dillon wants you to at least have when you measure with the calipers.What you are doing is getting all of the belling out of the case. Some like to have a heavier crimp. That will be up to you. But remember it increases pressure. When you look in your reloading manual Dillon is using the cases width as a starting crimp measurement. You can put more crimp on pistol loads, but not too much. I experienced with varying the crimp on .357 Magnum loads, but most of the time I dont put any more than what the manual says. __________________ Henry - Life NRA Member, USCCA Shield Member If con is the opposite of pro, is Congress the opposite of progress?

January 2, 2007, 09:08 PM	#9
amamnn Senior Member Join Date: May 13, 2006 Location: WA, the left armpit of the USA Posts: 1,323	That "crimp dimension" will apply only to rounds you crimp into a cannelure. Not all bullets have a cannelure, and an attempt to put so heavy a crimp in those that do not will result in deformation of the bullet. __________________ "If the enemy is in range, so are you." - Infantry Journal

January 2, 2007, 09:25 PM	#10
Rimrod Senior Member Join Date: October 19, 2005 Location: Behind enemy lines Posts: 1,309	.379? That would be no crimp at all!

January 2, 2007, 09:33 PM	#14
WSM MAGNUM Senior Member Join Date: September 30, 2006 Location: Maryland Posts: 750	Dillons instructions are not telling you how much crimp you have to have. They are just explaining on how to adjust the die to remove the belling by using a caliper. So, the measurement of .379 is what you should at least have. __________________ Henry - Life NRA Member, USCCA Shield Member If con is the opposite of pro, is Congress the opposite of progress?

January 2, 2007, 12:31 AM	#2
Rimrod Senior Member Join Date: October 19, 2005 Location: Behind enemy lines Posts: 1,309	What do you mean by "crimp measurement"?

January 2, 2007, 12:56 AM	#3
JJB2 Junior member Join Date: December 14, 2005 Posts: 558	that's a new term to me too..... i just run the bullet in to the crimp groove and set it there to roll the crimp in...... LIFE IS SHORT..................

January 2, 2007, 08:34 AM	#4
Rugerrat Member Join Date: February 20, 2005 Posts: 34	My Dillon dies instructions referred to a crimp measurement that should be obtained from reloading manual. None of my manuals had any reference to this. I am assuming it is a micrometer reading at the very top edge of the case after running through the crimp die.

January 2, 2007, 02:41 PM	#5
Rimrod Senior Member Join Date: October 19, 2005 Location: Behind enemy lines Posts: 1,309	Sorry Rugerrat, Iv'e never used Dillon dies. I've also never heard of that term either and I have a lot of reloading manuals. If no Dillon users jump in try and type that sentence, plus a couple before and after, and maybe we can figure it out.

January 2, 2007, 05:59 PM	#6
Rugerrat Member Join Date: February 20, 2005 Posts: 34	On last page of die instruction sheet in the section describing adjustment for proper crimp it reads "Note:refer to a loading manual for proper crimp dimension".

January 2, 2007, 06:36 PM	#7
kart racer Senior Member Join Date: April 23, 2005 Posts: 175	I measure a factory round and set it so it crimps in that ballpark and adjust from there.

January 2, 2007, 09:59 PM	#15
Rugerrat Member Join Date: February 20, 2005 Posts: 34	Thanks for all your help! I have followed this site for a couple of years and appreciate all the experience represented here.

January 3, 2007, 08:45 PM	#16
Rimrod Senior Member Join Date: October 19, 2005 Location: Behind enemy lines Posts: 1,309	You will need more crimp than that whether your bullet has a cannelure or not. Revolver ammo needs to be crimped to keep the bullets from pulling out of the cases from recoil. If the bullet has no cannelure then it should be crimped at the ogive or at the first driving band. Starting at .379 is not safe, you need a crimp beyond "straight". If the Dillon dies have a taper crimp area before the roll crimp is started that may work for light loads but that measurement will not be in any reloading manual, that will depend on how far it taper crimps before the roll starts.

January 3, 2007, 10:54 PM	#17
Scooter72 Member Join Date: December 25, 2005 Location: Wisconsin Posts: 36	When I started loading .38/.357 I thought I had enough crimp until I tried dropping a round into my cylinder. It stuck. So I adjusted my crimp a little at a time and kept checking the round with my cylinder until the round fell in freely. Never measured crimp just OAL.

January 3, 2007, 11:40 PM	#18
skipjack Senior Member Join Date: December 10, 2002 Location: Maryland, USA Posts: 140	The amount of crimp is going to depend on the bullet type, cannelure or lack of, and the amount of recoil generated by the round. Heavier loads need more crimp, lighter loads need less. I generally eyeball it, and use a lee factory crimp die. I prefer a cannelure on plated or jacketed bullets. If you are loading plated bullets, don't put too much crimp on the round or the plating will be deformed upon firing.