reloading - don't crimp

Artsi · 09-08-2002, 06:00 PM

There are actually very few handguns where bullet crimping is a necessity. Our belowed P08 isn't one of them.
Job that crimp will do is to hold bullet still while gun recoils. That will discourage bullets from sneaking outwards, thus increasing ammo overall lenght. That in return will cause malfunctions whether be it revolver or autoloader.

In short, adjust your crimp die such manner that it only, I repeat, it only straightens out bellbouth on brass. Friction is our friend which will secure bullet in it's place.

Why is 'properly done' crimp job bad?
There's nothing wrong with properly done crimping. Trouble is (according to what I've seen) to easily overshoot crimp die settings, and thus get overly crimped ammo. That in return will deform bullet (extent of damage varies from reloader to another). Deformed bullet will not fly as intended - bad accuracy results.

If we're nitpicking, let's dive a touch deeper.
During bellmouthing there is a kinda 'shaft' that runs deeper into brass. That will enlarge brass inside diameter suitable for bullet seating.
Dedicated reloader will have two different shafts. One for jacketed bullets, and another for lead bullets. Since lead bullet is a touch larger in diameter than it's jacketed counterpart, it needs just as much thicker 'shaft'.
Lead bullet will deform when it's forced into brass case if it's been bellmouthed with a jacketed bullet 'shaft'.

I've observed different brand dies to vary greatly in measurements. For example Dillon handgun dies seem to really overshoot in the resizing department. Even when one has their settings correct - the ammo will resemble by gone era Coca-Cola bottle.
I myself am keen to use RCBS carbide die sets for handgun calibers. Their way of engineering resizing die is like I want to have my die to be. Dillon overshoots the resizing and it does not resize brass all the way down. In an autoloader (when reloading used brass) that very easily will lead into feeding jam. What happens is that ammo gets rammed into chamber as ferociously as slide can manage, and the darn ammo will jam just fraction of an inch before being fully chambered. Jam is due to oversize brass near extractor groove area. This literally is a PITA to clear at shooting range - always have a cleaning rod in your shooting bag.

Given examples may not materialize as clearly in real world. My views present pretty extremes - either it's perfect or sub-standard.
In real world there are more gray areas, it's not really that black 'n' white. I just simplified matters. I hope no-one is offended by that.

-Artsi

Thor · 09-08-2002, 08:11 PM

The 9mm Luger HEADSPACES or the case stops on the front of the case or end of the case mouth, crimping beyound the flared mouth being just touching the bullet or the case end parallel with the bullet surface could result in the round going into the chamber too deep and a misfire might result.

[email protected] · 10-08-2002, 03:12 PM

In re roll v. taper crimp, I wonder if anyone knows the name of the stickum that the ammo manufacturers reportedly use on new ammo, to prevent the bullet from unseating. I have been told this will largely eliminate the need for anything but the lightest friction seating of the bullet, but I don't know what it is or where it can be purchased. For that matter, I don't even know if the ammo manufacturers really use such a thing.

Johnny Peppers · 10-08-2002, 05:00 PM

Rick,
In "Hatcher's Notebook" Gen. Hatcher discusses firing the .380 in the 9mm Luger. If the cartridge is fed from the magazine, the extractor captures the rim before the cartridge has a chance to go fully into the chamber. If the .380 is dropped directly into the chamber, it just drops into the chamber farther than the firing pin will reach. Gen. Hatcher reported excellent accuracy, but the .380 cartridge was not powerful enough to work the Luger action and the toggle had to be manually retracted and released after each shot.
Also, the Model 1911 Colt pistol cartridge headspaces on the forward edge of the chamber, but it too is captured by the extractor before the cartridge reaches the end of the chamber. As with the Luger, the cartridge slides up the breech face and under the extractor rather than the extractor jumping over the rim.

MarkC · 10-09-2002, 03:22 PM

I have really enjoyed this thread about reloading. The taper crimp is the way to go for semi-auto's as I have seen a roll crimp cause havoc because of the headspace issue as Thor pointed out.

Additionally, I might mention the added advantage of crimping in a seperate die from seating. This will make your ammo much more consistant/accurate.

Lee sells a die called the "factory crimp die" that has the additional benefit of a carbide sizing ring which will eliminate any "bulge" caused by the reloading process. I have found this useful in a few of my guns with custom 9mm barrels which chambers have tighter tolerances than mil spec barrels, where any slight bulge will cause feeding problems.

Doubs · 10-10-2002, 01:02 AM

[quote]Originally posted by Artsi:
<strong> Job that crimp will do is to hold bullet still while gun recoils. That will discourage bullets from sneaking outwards, thus increasing ammo overall lenght. That in return will cause malfunctions whether be it revolver or autoloader.
-Artsi</strong><hr></blockquote>

Yes....... and no. In a revolver, the bullet will tend to creep forward under recoil. A roll crimp will prevent it.

In an auto-loader, however, the bullet will be pounded deeper into the case and raise pressures. This is especially true of the 9mm.

The bullet in a revolver tries to remain in it's place while recoil snatches it rearward and attempts to pull the case away from it. Without a roll crimp to hold it in place, the bullet will move forward.

In an auto-loader, the whole cartridge tries to remain stationary while everything else recoils sharply to the rear. That brings the bullet violently into contact with the magazine's forward wall and will push the bullet deeper into the case. The easiest way to see this clearly is to load five softpoint cartridges into a bolt action rifle and fire the first four. Then check the nose of the fifth and note how battered it's become.

Some factory cartridges in 9mm will have a crimp ring around the case immediately below the base of the seated bullet. (Remington is one that does.) The crimp ring becomes a waist that is smaller than the portion of the case in front of it. It's sole purpose is to prevent the bullet from being driven deeper into the case under recoil.

Some older rifle cartridges intended for use in tube-fed rifles have waist crimps and mouth crimps because the cartridges are subjected to both forces under recoil.

09-08-2002, 06:00 PM	#1
Artsi User Join Date: Sep 2002 Location: Finland Posts: 61 Thanks: 0 Thanked 0 Times in 0 Posts	reloading - don't crimp There are actually very few handguns where bullet crimping is a necessity. Our belowed P08 isn't one of them. Job that crimp will do is to hold bullet still while gun recoils. That will discourage bullets from sneaking outwards, thus increasing ammo overall lenght. That in return will cause malfunctions whether be it revolver or autoloader. In short, adjust your crimp die such manner that it only, I repeat, it only straightens out bellbouth on brass. Friction is our friend which will secure bullet in it's place. Why is 'properly done' crimp job bad? There's nothing wrong with properly done crimping. Trouble is (according to what I've seen) to easily overshoot crimp die settings, and thus get overly crimped ammo. That in return will deform bullet (extent of damage varies from reloader to another). Deformed bullet will not fly as intended - bad accuracy results. If we're nitpicking, let's dive a touch deeper. During bellmouthing there is a kinda 'shaft' that runs deeper into brass. That will enlarge brass inside diameter suitable for bullet seating. Dedicated reloader will have two different shafts. One for jacketed bullets, and another for lead bullets. Since lead bullet is a touch larger in diameter than it's jacketed counterpart, it needs just as much thicker 'shaft'. Lead bullet will deform when it's forced into brass case if it's been bellmouthed with a jacketed bullet 'shaft'. I've observed different brand dies to vary greatly in measurements. For example Dillon handgun dies seem to really overshoot in the resizing department. Even when one has their settings correct - the ammo will resemble by gone era Coca-Cola bottle. I myself am keen to use RCBS carbide die sets for handgun calibers. Their way of engineering resizing die is like I want to have my die to be. Dillon overshoots the resizing and it does not resize brass all the way down. In an autoloader (when reloading used brass) that very easily will lead into feeding jam. What happens is that ammo gets rammed into chamber as ferociously as slide can manage, and the darn ammo will jam just fraction of an inch before being fully chambered. Jam is due to oversize brass near extractor groove area. This literally is a PITA to clear at shooting range - always have a cleaning rod in your shooting bag. Given examples may not materialize as clearly in real world. My views present pretty extremes - either it's perfect or sub-standard. In real world there are more gray areas, it's not really that black 'n' white. I just simplified matters. I hope no-one is offended by that. -Artsi __________________ A golf course is a waste of perfectly good rifle range. (- someone in the net-)

09-08-2002, 08:11 PM	#2
Thor User Join Date: Jun 2002 Location: Rio Rancho, New Mexico Posts: 4,583 Thanks: 958 Thanked 970 Times in 276 Posts	The 9mm Luger HEADSPACES or the case stops on the front of the case or end of the case mouth, crimping beyound the flared mouth being just touching the bullet or the case end parallel with the bullet surface could result in the round going into the chamber too deep and a misfire might result. __________________ Thor's Luger Clinic http://members.rennlist.com/lugerman/ Ted Green (Thor Yaller Boots) 725 Western Hills Dr SE, Rio Rancho, NM 87124 915-526-8925 Email [email protected] ----------------------------------- John3:3 Jesus answered and said to him, "Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God."

10-08-2002, 03:12 PM	#3
[email protected] User Join Date: Aug 2002 Location: Dallas, Texas Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	In re roll v. taper crimp, I wonder if anyone knows the name of the stickum that the ammo manufacturers reportedly use on new ammo, to prevent the bullet from unseating. I have been told this will largely eliminate the need for anything but the lightest friction seating of the bullet, but I don't know what it is or where it can be purchased. For that matter, I don't even know if the ammo manufacturers really use such a thing.

10-08-2002, 05:00 PM	#4
Johnny Peppers User Join Date: Jun 2002 Location: Calion, Arkansas Posts: 1,042 Thanks: 0 Thanked 1 Time in 1 Post	Rick, In "Hatcher's Notebook" Gen. Hatcher discusses firing the .380 in the 9mm Luger. If the cartridge is fed from the magazine, the extractor captures the rim before the cartridge has a chance to go fully into the chamber. If the .380 is dropped directly into the chamber, it just drops into the chamber farther than the firing pin will reach. Gen. Hatcher reported excellent accuracy, but the .380 cartridge was not powerful enough to work the Luger action and the toggle had to be manually retracted and released after each shot. Also, the Model 1911 Colt pistol cartridge headspaces on the forward edge of the chamber, but it too is captured by the extractor before the cartridge reaches the end of the chamber. As with the Luger, the cartridge slides up the breech face and under the extractor rather than the extractor jumping over the rim.

10-09-2002, 03:22 PM	#5
MarkC User Join Date: Jun 2002 Location: Boston, MA Posts: 478 Thanks: 1 Thanked 109 Times in 26 Posts	I have really enjoyed this thread about reloading. The taper crimp is the way to go for semi-auto's as I have seen a roll crimp cause havoc because of the headspace issue as Thor pointed out. Additionally, I might mention the added advantage of crimping in a seperate die from seating. This will make your ammo much more consistant/accurate. Lee sells a die called the "factory crimp die" that has the additional benefit of a carbide sizing ring which will eliminate any "bulge" caused by the reloading process. I have found this useful in a few of my guns with custom 9mm barrels which chambers have tighter tolerances than mil spec barrels, where any slight bulge will cause feeding problems.

10-10-2002, 01:02 AM	#6
Doubs User Join Date: Jun 2002 Location: Byron, Georgia Posts: 1,700 Thanks: 792 Thanked 1,692 Times in 555 Posts	[quote]Originally posted by Artsi: <strong> Job that crimp will do is to hold bullet still while gun recoils. That will discourage bullets from sneaking outwards, thus increasing ammo overall lenght. That in return will cause malfunctions whether be it revolver or autoloader. -Artsi</strong><hr></blockquote> Yes....... and no. In a revolver, the bullet will tend to creep forward under recoil. A roll crimp will prevent it. In an auto-loader, however, the bullet will be pounded deeper into the case and raise pressures. This is especially true of the 9mm. The bullet in a revolver tries to remain in it's place while recoil snatches it rearward and attempts to pull the case away from it. Without a roll crimp to hold it in place, the bullet will move forward. In an auto-loader, the whole cartridge tries to remain stationary while everything else recoils sharply to the rear. That brings the bullet violently into contact with the magazine's forward wall and will push the bullet deeper into the case. The easiest way to see this clearly is to load five softpoint cartridges into a bolt action rifle and fire the first four. Then check the nose of the fifth and note how battered it's become. Some factory cartridges in 9mm will have a crimp ring around the case immediately below the base of the seated bullet. (Remington is one that does.) The crimp ring becomes a waist that is smaller than the portion of the case in front of it. It's sole purpose is to prevent the bullet from being driven deeper into the case under recoil. Some older rifle cartridges intended for use in tube-fed rifles have waist crimps and mouth crimps because the cartridges are subjected to both forces under recoil.