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Crimping Cartridges


fasteddie
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Do any of you that reload , crimp your cartridges . I ahd folks tell me not to as it would allow pressure buildup in rounds . The guy at the gun store told me that I definately should use a crimp die and he knows that I have them so he's not trying to sell me something . Opinions ???

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I have crimped previosuly and may do so in future.

One reason you may wish to crimp is if you are hunting with tubular magazine. Say a 30-30. If the projectile is pushed further into the case than it is originally loaded, it increases pressures, sometimes exponentially. Without the crimp, this is a possibility depending on neck tension.

On some projectiles, the design allows for crimp with a depression ring to roll the crimp into....

The amount you crimp is adjustable. When I do crimp, it is almost imperceptable as I do not want to deform my projectile.

On those occasions where I have used crimp die it was to try and get consistant pressure in seeking out a bit more accuraccy.

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Do any of you that reload , crimp your cartridges . I ahd folks tell me not to as it would allow pressure buildup in rounds . The guy at the gun store told me that I definately should use a crimp die and he knows that I have them so he's not trying to sell me something . Opinions ???

I always crimp revolver rounds in the bullet's cannelure. Don't want them to back out upon recoil. I also crimp in the cannelure groove for large-bore lever action rounds (.444 Marlin).

For bolt action rifles I do not crimp, but for a semi-auto (M1) I may put a slight crimp when the bullet has a cannelure.

For 9mm & .45ACP I will use a taper crimp die and slightly crimp to ensure there will be no bullet setback when worked in the action.

I have not heard of increased pressures caused by a crimp, but if there is bullet movement backwards into the case, you will get increased pressures. Too much crimp can deform a bullet and cause accuracy problems.

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Thanks . I appreciate the replies .

The first few rounds I had done for my son's 270 , I had used the regular decapping die . Some rounds were fired in a different rifle and the bullets would go in loose so I pulled them ot . With the next few rounds I used the full size die and that worked great except that I had to lube the cases . Now I am considering whether or not to crimp the rounds as I believe a light crimp is done with factory ammo .

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I loaded up 65 cartridges for my son's 270 this afternoon . I took the last 15 rounds and gave them a light crimp .

I had to hand weigh each charge on mu Ohaus Balance scale and I was having trouble with the funnel . Static was keeping all the powder from flowing and I had to tap the the funnel quite a bit to get all the powder out . I grabbed one of those laundry dryer sheets , wiped out the funnel and it worked fine after that .

I have an old Lyman powder measure but I can't get it to work with Reloader 19 ..............alt=screw uhttp://www.downsouthhuntingforums.com/images/smiles/pissed.gif[/img]

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Thanks . I appreciate the replies .

The first few rounds I had done for my son's 270 , I had used the regular decapping die . Some rounds were fired in a different rifle and the bullets would go in loose so I pulled them ot . With the next few rounds I used the full size die and that worked great except that I had to lube the cases . Now I am considering whether or not to crimp the rounds as I believe a light crimp is done with factory ammo .

I suspect factory rounds are lightly crimped to cover all the bases for the applications they will be used in to prevent the bullet from moving. I think it's CYA on the ammomaker's part.

If you are full-length resizing or even partial resizing, you will reduce the case neck enough to get a firm grip on the bullet when you seat it. In a bolt-action rifle, I have never experienced the bullets moving after I've seated them and I usually never crimp them for that type of rifle. 

Remember, those presses exert a lot of pressure on the stroke when seating the bullet. Just try moving a bullet with your fingers once it's seated. You'll find it's in there pretty tight.

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I have never crimped any of my centerfire rifle ammo ... I full length resize all my casings and have never had any problem with bullets moving, either with a semi ( M1 Garand) or some cartridges with fairly stout recoil ( .338 WM, 9.3 x 62)...

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The 444 is awesome on deer

I've used one bullet all these years, Hornady's 265gr. FP in my older Marlin. Haven't tried the newer bullets in my gun yet.

This is an interesting post from the Marlin owners forum on handloads and penetration testing with various 240 gr. bullets. 

http://www.marlinowners.com/forums/index.php/topic,56314.0.html

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  • 3 months later...

I only crimp straight wall casings.  As for presure build up.  Yes it will CPU of presure but not to a dramatic amount.  I use just a light roll crimp.  It seams to help with feeding in semi pistols as well as in my personal carry pistol. I am putting the one in the tube every day before I leave the house.  And the constant slamming of the slid will move the bullet, if not crimped. I have never seen a need for it in a center fire rifle.  I shoot a light weight 350rem.  The recoil is so bacd that, after you shoot the first shot. The SP ammo in the mag well all become flat points. With no bullet slip.

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Depends on the load.  One load I've used for my .45 Colt I had to put a pretty heavy crimp on it because I was using a fairly light load of slow burning powder and without a good heavy crimp I was having problems with not building enough pressure.

I have Lee "Factory Crimp" dies that I use with a couple cartridges I reload.

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  • 3 months later...

crimping keeps the horizonal alignment of the printing closer to 180 degrees.  Other than that it doesn't provide much more terminal benefit.  If I have a loading that is printing all over the paper, I might print as a way to contol the group and make it tighter.  I would also play around with the AOL to reduce the distance of the jump in the chamber. 

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