Overcrimping and jams due to undercrimping

[ChrisMkIV]

I used to do a lot of my own 45acp loads, and own about 3 re-loading mannuals, but still run into either a crimp that was excessive or
a loose crimp that would jam going up the ramp, factory ammo worked just fine, but not my reloads? why can I find no middle ground?


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"The supreme power in America cannot enforce unjust laws by the sword, becuse the entire population will be armed"
Alexander Hamilton

[Fred J. Drumheller]

What type of crimp are you attempting?

Roll Crimp? Bad idea in a semi-auto!

Taper Crimp? Crimp just enough to remove the flair on the case mouth. You're not trying to crush the case into the bullet.


Yr. Obt. Svnt.

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Fred J. Drumheller
NRA Life
NRA Golden Eagle

[Yanus]

A good way to adjust a taper crimp die
is to insert a factory round and run the
ram all of the way up. Then screw the
crimp die down until it just touches the
case. This will give you a crimp close
to factory.

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Never do an enemy a minor injury. Machiavelli
"Stay alive with a 45"

[alan]

Chris:

I reload 45 auto using both commercial and military brass, one hell of a mixture, matter of fact. In any event, using TAPER CRIMP, I set the die (trial and error) so that the case o.d., at the case mouth of a reload is .470" dia. This dimension seems to work fine is 2 different pistols.

Insufficient taper crimp can cause feed failures(jams), to much crimp can reduce bullet diameter, leading to poor accuracy, might also crumple cases.

[ChrisMkIV]

While stationed in Fallon, NV at N.A.S. Fallon(I did 10 years in the Navy building bombs) I came across alot of military brass,still have alot, and it always worked just fine, I guess I am going to have to use a factory round as a guide, and make sure I am using the best crimp method(taper was it?)
and be more accurate with my calipier.

Thanks guys!

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"The supreme power in America cannot enforce unjust laws by the sword, becuse the whole body of the people are armed"
Alexander Hamilton

[alan]

Chris:

Re determininmg if one has enough crime, taper crimp for a pistol cartridge, try the following. You might carry out the following with a "dummy cartridge".

You have seated a bullet into a sized case, NO POWDER, and have roughly set your taper crimp die. Stand the dummy round, base down, on a bathroom scale. Using something you can easily hold, a piece of 2 x 4 for instance, put a load on the projectile, 20 t0 25 pounds should do it. If thew crimp does not hold the bullet against this loading, similar to what the rounb experiences during the feeding cycle, increase the crimp till it does. Aside from this, respecting the 45ACP, a finished diameter over case mouth of .470" usually provides siufficient taper crimp, with cast lead bullets of .452" diameter.

[MADISON]

Use a TAPER CRIMP! Put only enough on until you feel "good" resistance.

If you are cheap??? you can pull the de-capping stim out of the sizer die and re-adjust it to do the taper crimping.

[ChrisMkIV]

Sounds like the taper crimp is the way to go.

I have a cool RCBS carbide set, no lube needed!

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"The supreme power in America cannot enforce unjust laws by the sword, becuse the whole body of the people are armed"
Alexander Hamilton

[EQP]

Chris,

You might also take a look at the type of bullet your using as the cause of your problems. Are your reloads using the same grain and shape bullet that the factory stuff is? I ran into a problem with my 1911 not liking 200grn SWC bullets but is happy as a clam with 185grn JHP's or 230grn LRN's.

Just a thought.
Evan

[ChrisMkIV]

anything with a round nose has always fed well, maybe its a ramp problem?

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"The supreme power in America cannot enforce unjust laws by the sword, becuse the whole body of the people are armed"
Alexander Hamilton

[tstr]

I just solved a problem which I thought was crimp related but wasn't. I had purchased flat nosed led bullets for my .45 and loaded them according to the closest specs I could find in any of my books. They fired fine through my Sig P220 but jammed up several times in my buddy's Glock 21. I thought it was a crimp problem and tightened up the crimp till is curled the bullet. It took me a bit to figure out that it wasn’t the crimp but was rather the seating depth that was giving me problems. The body of the bullet was catching in the barrel rifling before the round was completely chambered leaving the slide stuck at about 1/16th of an inch from closed. Seating the bullet deeper fixed the problem. The bullet diameter should begin tapering almost immediately above the case mouth. If it begins to taper below (inside) the case mouth it is too deep. If it doesn't start to taper right away above the case mouth, it is too shallow.

This probably isn’t your problem, but I thought I’d mention it incase it helped somebody.

Don

[ChrisMkIV]

I did not even think about bullet depth in the case, and with my SS match barrel there was no room for any slop, good advice, I will have to check my "OAL" table to be sure.

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"The supreme power in America cannot enforce unjust laws by the sword, becuse the whole body of the people are armed"
Noah Webster

[Big Bunny]

Try no "crimp" atall, just a good interference fit can work well depending upon your dies.

Good point on OAL and bullet taper.

The throat can be gunsmithed if all else fails.

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***Big Bunny***