Crimping ? - The Firearms Forum

Todd 68 · 03-26-2009, 03:18 PM

I have been reloading Rifle cartridges for some time but have never loaded any that requires crimping , I am starting my reloading adventure with pistols and my first one is a 45ACP. I was wondering if there was a way to gauge the amount of crimp that I use with my digital calipers . The man at the gun shop here told me that he had a paper at home that had the measurement for pistol crimping and I was wondering if any of you guys could tell me where I can get this info because I am looking at loading several differnt calibers and this info seems to be very important .
Thanks Todd

johnlives4christ · 03-26-2009, 07:43 PM

lyman reloading manual would tell you i think

olmossbak · 03-26-2009, 07:44 PM

Don't crimp 45 acp with your bullet seating die. That ctg headspaces on the ctg rim and crimping (roll type) will result in misfires. There are taper crimp dies available for this purpose but I've never had to use them on any ctg developed for auto pistols.

Revolver ctgs are a whole different matter as shooting the pistols will cause bullet creep and can cause the cylinder to jam in the frame. This is especially true in hot 357, 41, and 44mags. There are probably others. Most loading manuals will specify crimps on straight wall revolver ctgs. You also need to crimp rifle ctgs loaded for tubular mags.

muddober · 03-26-2009, 11:28 PM

Your 45 acp ammo should only be tapper crimped and not roll crimped as olmossbak pointed out. I will expand on that just a bit because I think he meant that case headspaces on the mouth of the case and not the "rim". Most but not all 45 acp bullet seating dies will only let you tapper crimp meaning you really can't see the crimp because of the tapper. While I have reloaded thousands of 45 acp I have never measured the very mouth of the case so that I can not tell you an actual measurement. When loading for a revolver (unless it is a 45 acp) you must always roll crimp the bullets to insure that they do not move forward during recoil of previously fired shots. I hope that helps.

Ron

Bruce FLinch · 03-28-2009, 09:01 AM

.001-.003 should be enough crimp. (That's thousandths)

Measure the case where ther middle of the bullet rests. Then measure where the case edge meets the bullet. For .45 & most Semi-Auto ammo, you need just enough crimp to hold the bullet & have a smooth transition for the round to slide into the chamber. When you slide your finger from bullet down to the case, it should feel smooth. You'll still feel the transition, but not a abrubt edge.

townmarshal · 03-28-2009, 04:17 PM

I've also found that with either taper or roll crimping, the oal can be up to
.005 longer after crimping. Not a big deal but something to be aware of.

JLA · 03-28-2009, 04:46 PM

crimping will almost always increase the consistency of your ammo. You will not notice a difference unless you shoot for accuracy and own a chrony though.

Todd 68 · 03-28-2009, 08:54 PM

Hey thanks guys I loaded some up for the first time last night and they shot good , I worked up some different loads and I got one batch to shoot 1 1/4 inches at 15 yards . I think that is pretty good for a home protection gun .

JLA · 03-28-2009, 09:39 PM

what are you protecting your home from? rats? chihuahuas? large carnivorous insects??? 1.25 inches is well within the combat accuracy required for home protection. I use a 12 ga scattergun myself. I hate chihuahuas

03-26-2009, 03:18 PM	#1
Todd 68 Member Join Date: Mar 2009 Location: Hurricane , West Virginia Posts: 7	Crimping ? I have been reloading Rifle cartridges for some time but have never loaded any that requires crimping , I am starting my reloading adventure with pistols and my first one is a 45ACP. I was wondering if there was a way to gauge the amount of crimp that I use with my digital calipers . The man at the gun shop here told me that he had a paper at home that had the measurement for pistol crimping and I was wondering if any of you guys could tell me where I can get this info because I am looking at loading several differnt calibers and this info seems to be very important . Thanks Todd -->

03-26-2009, 07:43 PM	#2
johnlives4christ Former Guest Join Date: Apr 2008 Location: Kentucky Posts: 3,828	Re: Crimping ? lyman reloading manual would tell you i think

03-26-2009, 07:44 PM	#3
olmossbak V.I.P. Member Join Date: Feb 2009 Location: NE Tenn Posts: 212	Re: Crimping ? Don't crimp 45 acp with your bullet seating die. That ctg headspaces on the ctg rim and crimping (roll type) will result in misfires. There are taper crimp dies available for this purpose but I've never had to use them on any ctg developed for auto pistols. Revolver ctgs are a whole different matter as shooting the pistols will cause bullet creep and can cause the cylinder to jam in the frame. This is especially true in hot 357, 41, and 44mags. There are probably others. Most loading manuals will specify crimps on straight wall revolver ctgs. You also need to crimp rifle ctgs loaded for tubular mags.

03-26-2009, 11:28 PM	#4
muddober Advanced Senior Member Join Date: Sep 2008 Posts: 1,436	Re: Crimping ? Your 45 acp ammo should only be tapper crimped and not roll crimped as olmossbak pointed out. I will expand on that just a bit because I think he meant that case headspaces on the mouth of the case and not the "rim". Most but not all 45 acp bullet seating dies will only let you tapper crimp meaning you really can't see the crimp because of the tapper. While I have reloaded thousands of 45 acp I have never measured the very mouth of the case so that I can not tell you an actual measurement. When loading for a revolver (unless it is a 45 acp) you must always roll crimp the bullets to insure that they do not move forward during recoil of previously fired shots. I hope that helps. Ron Last edited by muddober; 03-26-2009 at 11:30 PM..

03-28-2009, 09:01 AM	#5
Bruce FLinch Advanced Senior Member Join Date: Aug 2005 Location: Bay Point, Kali..aka Gun Point Posts: 5,016	Re: Crimping ? .001-.003 should be enough crimp. (That's thousandths) Measure the case where ther middle of the bullet rests. Then measure where the case edge meets the bullet. For .45 & most Semi-Auto ammo, you need just enough crimp to hold the bullet & have a smooth transition for the round to slide into the chamber. When you slide your finger from bullet down to the case, it should feel smooth. You'll still feel the transition, but not a abrubt edge. __________________ A bad day @ the Range, is better than a good day @ work.

03-28-2009, 04:17 PM	#6
townmarshal Member Join Date: Nov 2008 Location: Indiana Posts: 6	Re: Crimping ? I've also found that with either taper or roll crimping, the oal can be up to .005 longer after crimping. Not a big deal but something to be aware of.

03-28-2009, 04:46 PM	#7
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,308	Re: Crimping ? crimping will almost always increase the consistency of your ammo. You will not notice a difference unless you shoot for accuracy and own a chrony though. __________________ 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!

03-28-2009, 08:54 PM	#8
Todd 68 Member Join Date: Mar 2009 Location: Hurricane , West Virginia Posts: 7	Re: Crimping ? Hey thanks guys I loaded some up for the first time last night and they shot good , I worked up some different loads and I got one batch to shoot 1 1/4 inches at 15 yards . I think that is pretty good for a home protection gun .

03-28-2009, 09:39 PM	#9
JLA TFF Moderator/Host Join Date: Feb 2007 Location: Heart Of Texas Contributor Posts: 17,308	Re: Crimping ? what are you protecting your home from? rats? chihuahuas? large carnivorous insects??? 1.25 inches is well within the combat accuracy required for home protection. I use a 12 ga scattergun myself. I hate chihuahuas __________________ 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!