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Re: 45 ACP out of Spec

Posted: 06 Aug 2022 13:39
by Ohio3Wheels
killian6pk wrote:I'll try that. I believe after taking a few of these apart and resizing and seating (without powder) to set up my dies, that what happened was these were never taper crimped. When I checked the dummies I made they also would not fit into the gauge. I was under the impression that you did not need to crimp .45 and 9's. Was I wrong?
I always taper crimp my 9mm and 45 cases. Usually just a bit more than it takes to get rid of any flair.

Make smoke,

Re: 45 ACP out of Spec

Posted: 06 Aug 2022 15:33
by killian6pk
I did the plop test in my barrel and the one's that I was concerned about went in just fine. They also loaded into the magazine without any problem. I think I am just going to taper crimp them and use them. I might seat them just a little more since they are a little over spec. just to ease my brain. Thanks for all the help.

Re: 45 ACP out of Spec

Posted: 06 Aug 2022 19:39
by RBHarter
Taper vs roll crimp .

A taper crimp just tapers the mouth to hold enough to stop pull and leave the case mouth up enough to stop on the chamber step . A roll crimp "hides" the case mouth from the chamber step .
The ACP types headspace on the case mouth . They may need to be crimped to fit the chamber .

Thoughts to think .
you have a standard dimension . You have a minimum and maximum tolerance . You have that for chambers , dies , and case gauges . Now if Bob's mega gun works buys a 100 reamers for the discount and they order them per drawing XXX with a .483 mouth and a .454 throat with a .484 head . They finish 20 chambers and sharpen the tool . Repeat . It's not long and the throat is down to .451 , .479 mouth , and a .480 head .

Now Bob's die supply orders reamers for to finish size of.4785 mouth and a .4795 head .

Williams has a case gauge reamed straight at .4805-.4819 .

That's all good until we get a batch of .4528 bullets , a first cut die and and gauge with a last cut chamber .

The chamber is cut maybe.002 under minimum that's great for brass life with the die cut .001 over max it just barely sizes it . It'll probably be loose in the gauge ..... Catch fired brass may be loose in the gauge too and loaded cartridges might not chamber even if they gauge .

Now add to this that some makers use a correct taper chamber while others use a straight wall chamber and another may use a chamber that only has a half taper .

In the US we have 10 makers of 45 ACP and a dozen or more imports , 4-5 major die makers and 8 reamer manufacturers .
Those jobs run about 220 days per yr the guys at finish ream may or may not touch up their reamers before they send them back to the house grinders . Now on any given day you have 100s of in spec variations.

The best answer is if it fits in your chamber then it's the right spec .