Taper crimp for .45 ACP


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SingleStack
March 22, 2006, 03:45 PM
Forgive me if this has been covered, but I searched this forum and didn't find an answer...

I've been reloading .45 ACP and seating/taper crimping at the same time with an RCBS die (I'm going to buy a Lee FCD soon). I measure case length using a Dillon OAL guage after resizing and after seating/crimping. I drop tested some of the finished product in my 45 barrel and the rounds fell nicely in the chamber, but needed a gentle push to seat all the way.

So, my question is how do you know you have the proper amount of crimp? I read in Wilson's 45 guide that he uses a taper crimp of .469 at the case mouth. Is it just a matter of crimping and measuring across the case mouth with a caliper?

My son made an obeservation while we were shooting Sunday and said that my 45 was throwing a lot of debris out the barrel when I shot reloads. Is this unburned powder that didn't ignite due to too little crimp? i.e. bullet starts to move before all the powder?

Thanks!

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1911user
March 22, 2006, 04:06 PM
You need to crimp a little more if they will not drop freely into the chamber of their own weight. You measure the crimp with calipers across the outside of the case mouth.

LHB1
March 22, 2006, 04:19 PM
Quote: "My son made an obeservation while we were shooting Sunday and said that my 45 was throwing a lot of debris out the barrel when I shot reloads. Is this unburned powder that didn't ignite due to too little crimp? i.e. bullet starts to move before all the powder?"

What powder/bullet are you using? Taper crimping on .45 ACP is basically to remove case flare and allow easy feeding/seating in chamber. Bullet retention comes from case resizing which should hold bullet with sufficient tension. If you are blowing unburned powder out the muzzle, perhaps you need to increase your load slightly (if possible to do so safely) OR switch to a faster powder?

Good shooting and be safe.
LB

JDGray
March 22, 2006, 07:29 PM
A good tapper crimp is needed to help prevent bullet setback in autos. .469 is where I crimp, I believe that is what WWB ammo is crimped at. Lee factory crimp dies work great, and its much simpler to seperate bullet seating and crimping.:)

LHB1
March 22, 2006, 08:30 PM
JD,
The taper crimp may indeed "help" somewhat to prevent bullet setback but many of us believe the primary tension for bullet retention is the sizing of the case to below bullet diameter. When the bullet is seated, it expands the case which then grips the bullet very tightly. I believe the taper crimp is primarily to remove case flare and improve cartridge feeding/seating. I seat and taper crimp my .451 cast bullets in a single step using an RCBS seat/crimp die to .469-.470 diameter.

Good shooting and be safe.
LB

SingleStack
March 22, 2006, 08:46 PM
Quote: LHB1..."What powder/bullet are you using? Taper crimping on .45 ACP is basically to remove case flare and allow easy feeding/seating in chamber. Bullet retention comes from case resizing which should hold bullet with sufficient tension. If you are blowing unburned powder out the muzzle, perhaps you need to increase your load slightly (if possible to do so safely) OR switch to a faster powder? "

I was using Unique and Montana Gold 230 gr. CMJ and also the 200 gr. FP.

Thanks to all for all the feedback so far!

LHB1
March 22, 2006, 10:17 PM
SingleStack,
Unique could be contributing to the ejecta/unburned powder since it is a "medium" burning rate pistol powder. If you like it, stick with it. If you want to experiment, you might try a "faster" burning rate powder, i.e. W231, Bullseye, etc. The faster burn rate powders may burn more completely in the relatively low pressure .45 ACP loads and thus have less ejecta/unburned powder blown out of the barrel. My choice for .45 ACP is W231 with 200 gr cast bullets. Good luck.

Good shooting and be safe.
LB

Lennyjoe
March 22, 2006, 10:55 PM
I also love W231 with 230gr plated bullets. For cast I'm using Unique.

The Bushmaster
March 23, 2006, 01:19 AM
What LHB1 says...I dito...:)

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