Enough or Not Enough Crimp???

PALongbow · February 16, 2002, 10:24 PM

I'm loading for my Ruger SRH revolver in 44 mag. How do I know if there is enough crimp or not on the bullet. It looks as if there is a real slight roll crimp into the cannelure.

Ron

sricciardelli · February 16, 2002, 11:10 PM

Press down on the bullet as hard as you can with your thumb...if the bullet slides into the case, you need more crimp.

tonyz · February 16, 2002, 11:40 PM

Recommend Redding Profile Crimp Die.

Tony

http://www.redding-reloading.com/pages/crimpdies.html

Steve Smith · February 17, 2002, 12:07 AM

You don't need a ton of crimp. Basically just enough to take the bell out. Case tension does most of the work for you. Try this:

Load some ammo. Measure your OAL and write it down. Load your SRH, and only shoot 5 rounds. Load it again, and shoot the fresh rounds, leaving the one that was there from earlier. Do this a coubel of times. If the case OAL hasn't grown significantly (or at all) you're good to go.

This becomes very important to consistent loads and for heavy loads that have the bullet at the very end of the chamber.

WESHOOT2 · February 17, 2002, 11:30 PM

'Roll' about .002" into the cannelure.
Heavy.

Ben Shepherd · February 18, 2002, 08:07 PM

WS2, do you crimp that heavy on a light plinker as well? Say 7.6 grains of unique(or in your case universal clays) under a 240 gr swc?

If so, I imagine it is for consistency purposes, correct?

Also are you talking .002 less diameter right at the crimp, or .002 worth of case metal length irrespective of diameter at the crimp?

WESHOOT2 · February 19, 2002, 08:00 PM

Yes.

Yes.

.002" of case material........(diameter matters in auto-loading cartridges).

WESHOOT2 · February 19, 2002, 08:03 PM

Please don't consider MY advice as absolute, since all guns are always different.
Highly recommend trying various crimps with your specific gun/ammo combination; perhaps you will find a "sweet-spot" crimp that tightens your groups.

My advice is general, a decent starting point, safe in any Magnum-type cartridge.

Ben Shepherd · February 19, 2002, 08:53 PM

I understand, but I've never actually measured my crimp before. So I was wondering (as a starting point) which way you are measuring, width or depth, not saying this will be perfect for my gun.

WESHOOT2 · February 20, 2002, 12:04 AM

.002" of case material regardless of cartridge diameter.

Ben Shepherd · February 20, 2002, 01:53 PM

Thank you. I'm here to learn. Glad you're willing to share your experience.

WESHOOT2 · February 21, 2002, 08:44 AM

I've been worrying over the "perfect crimp" since 1977...............

stans · February 22, 2002, 07:50 AM

Ok, I have just finished some informal testing. Using a Smith & Wesson M19-3 with a four inch barrel, 3.6gr W-231, WSP primers, Bull-X 148gr DEWC, brass used was both Federal and Midway 357 Magnum. Rounds were loaded to the same OAL and given either no crimp, just removed the belling, or a moderate crimp (case diameter, measured just below the mouth, after bullet seating -0.004 inch).

Range results: Chronograph revealed that all rounds, regardless of case, were 20 fps faster with a crimp. The crimped rounds also had half the extreme spreads in velocity. The rounds in Federal cases were only slightly more accurat with crimps, the Midway cases showed a great benefit from crimping.

Years ago I heard that crimping would destroy accuracy, yet my results suggest otherwise. More research may be needed. Oh drat, that means more time at the loading bench and the range. Well, it's a tough life, but someone has to do it.

Mikul · February 22, 2002, 01:31 PM

Put as much crimp on as you can without denting the bullet. This turns out to be very little. You may need to pull four or five bullets to find out if you're doing it right.

This is probably where the ruined accuracy tales originate. Too heavy of a crimp can cause jackets to rip off while the dent in the bullet is another shock wave for the bullet's aerodynamics to deal with.

Frank Iacono · February 26, 2002, 09:02 PM

You should be able to see a slight roll of the case mouth into the bullet canulure. To check your amount of crimp: load the Ruger with 6 rounds and fire 5 rounds, examine the unfired sixth round. If you have sufficient crimp, the cartridge will appear to have a visually identical crimp/canulure relationship to a round not subjected to five recoil cycles of the handgun.

C.R.Sam · February 26, 2002, 09:52 PM

Stans just demonstrated the value of crimp in a super light load.

I think the benefits will be even greater with heavier loads.

Sam

riflemanZ · February 27, 2002, 10:27 PM

I like the Lee Factory crimp die.

February 16, 2002, 10:24 PM	#1
PALongbow Senior Member Join Date: December 30, 2001 Location: SE Pennsylvania Posts: 103	Enough or Not Enough Crimp??? I'm loading for my Ruger SRH revolver in 44 mag. How do I know if there is enough crimp or not on the bullet. It looks as if there is a real slight roll crimp into the cannelure. Ron

February 17, 2002, 11:30 PM	#5
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	REDDING PROFILE CRIMP DIE 'Roll' about .002" into the cannelure. Heavy.

February 19, 2002, 08:00 PM	#7
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	BEN Yes. Yes. .002" of case material........(diameter matters in auto-loading cartridges).

February 19, 2002, 08:03 PM	#8
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	.....IN YOUR GUN..... Please don't consider MY advice as absolute, since all guns are always different. Highly recommend trying various crimps with your specific gun/ammo combination; perhaps you will find a "sweet-spot" crimp that tightens your groups. My advice is general, a decent starting point, safe in any Magnum-type cartridge.

February 20, 2002, 12:04 AM	#10
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	TOP TO BOTTOM .002" of case material regardless of cartridge diameter.

February 16, 2002, 11:10 PM	#2
sricciardelli Senior Member Join Date: August 13, 2001 Location: Montana Posts: 489	Press down on the bullet as hard as you can with your thumb...if the bullet slides into the case, you need more crimp.

February 16, 2002, 11:40 PM	#3
tonyz Senior Member Join Date: January 29, 2000 Location: Wa Posts: 922	Recommend Redding Profile Crimp Die. Tony http://www.redding-reloading.com/pages/crimpdies.html

February 17, 2002, 12:07 AM	#4
Steve Smith Senior Member Join Date: December 9, 1999 Posts: 4,131	You don't need a ton of crimp. Basically just enough to take the bell out. Case tension does most of the work for you. Try this: Load some ammo. Measure your OAL and write it down. Load your SRH, and only shoot 5 rounds. Load it again, and shoot the fresh rounds, leaving the one that was there from earlier. Do this a coubel of times. If the case OAL hasn't grown significantly (or at all) you're good to go. This becomes very important to consistent loads and for heavy loads that have the bullet at the very end of the chamber.

February 18, 2002, 08:07 PM	#6
Ben Shepherd Senior Member Join Date: August 11, 2001 Location: Utah Posts: 1,462	WS2, do you crimp that heavy on a light plinker as well? Say 7.6 grains of unique(or in your case universal clays) under a 240 gr swc? If so, I imagine it is for consistency purposes, correct? Also are you talking .002 less diameter right at the crimp, or .002 worth of case metal length irrespective of diameter at the crimp?

February 19, 2002, 08:53 PM	#9
Ben Shepherd Senior Member Join Date: August 11, 2001 Location: Utah Posts: 1,462	I understand, but I've never actually measured my crimp before. So I was wondering (as a starting point) which way you are measuring, width or depth, not saying this will be perfect for my gun.

February 20, 2002, 01:53 PM	#11
Ben Shepherd Senior Member Join Date: August 11, 2001 Location: Utah Posts: 1,462	Thank you. I'm here to learn. Glad you're willing to share your experience.

February 21, 2002, 08:44 AM	#12
WESHOOT2 Senior Member Join Date: February 20, 1999 Location: home on the range; Vermont (Caspian country) Posts: 14,324	YOU'RE WELCOME I've been worrying over the "perfect crimp" since 1977...............

February 22, 2002, 07:50 AM	#13
stans Senior Member Join Date: November 9, 2001 Location: Virginia, USA Posts: 838	Ok, I have just finished some informal testing. Using a Smith & Wesson M19-3 with a four inch barrel, 3.6gr W-231, WSP primers, Bull-X 148gr DEWC, brass used was both Federal and Midway 357 Magnum. Rounds were loaded to the same OAL and given either no crimp, just removed the belling, or a moderate crimp (case diameter, measured just below the mouth, after bullet seating -0.004 inch). Range results: Chronograph revealed that all rounds, regardless of case, were 20 fps faster with a crimp. The crimped rounds also had half the extreme spreads in velocity. The rounds in Federal cases were only slightly more accurat with crimps, the Midway cases showed a great benefit from crimping. Years ago I heard that crimping would destroy accuracy, yet my results suggest otherwise. More research may be needed. Oh drat, that means more time at the loading bench and the range. Well, it's a tough life, but someone has to do it.

February 22, 2002, 01:31 PM	#14
Mikul Senior Member Join Date: March 21, 2000 Posts: 1,396	Put as much crimp on as you can without denting the bullet. This turns out to be very little. You may need to pull four or five bullets to find out if you're doing it right. This is probably where the ruined accuracy tales originate. Too heavy of a crimp can cause jackets to rip off while the dent in the bullet is another shock wave for the bullet's aerodynamics to deal with.

February 26, 2002, 09:02 PM	#15
Frank Iacono Member Join Date: February 25, 2002 Location: vermont Posts: 18	Crimp You should be able to see a slight roll of the case mouth into the bullet canulure. To check your amount of crimp: load the Ruger with 6 rounds and fire 5 rounds, examine the unfired sixth round. If you have sufficient crimp, the cartridge will appear to have a visually identical crimp/canulure relationship to a round not subjected to five recoil cycles of the handgun.

February 26, 2002, 09:52 PM	#16
C.R.Sam Senior Member Join Date: October 30, 1999 Location: Dewey, AZ Posts: 12,858	Stans just demonstrated the value of crimp in a super light load. I think the benefits will be even greater with heavier loads. Sam

February 27, 2002, 10:27 PM	#17
riflemanZ Member Join Date: February 16, 2002 Location: milwaukee wi Posts: 20	I like the Lee Factory crimp die.