Checking the Crimp?

[billmc2]

Yesterday I was reading an article in Handloader magazine written by Brian Pearce. The article was titled Loading The .45 ACP. (https://www.handloadermagazine.com/loading-the-45-acp-pet-loads)

In the article he says
"The crimp should measure .470 inch, which can be measured at the case mouth using blade calipers."

I have wondered how do I know if I've gotten the crimp correct and here he gives me a measurement I can use to verify what I have done. I have looked in several of the reloading manuals I have and I do not find a reference like this in any of them. (I have not yet tried loading the .45 ACP, I do have the dies and components to do so, I just haven't gotten around to it.) I assume that if this information is available for one cartridge then it must be available for the others. Where do I get information like this? In this case he is dealing with a taper crimp is there something similar for roll crimps?

[mdi]

I do not measure any semi-auto case crimp. Actually I do not "crimp" any either. I just deflare with a deflaring die (aka taper crimp die) and plunk test. Bullets are held in place on semi-auto cartridges by neck tension, not a crimp. Works for my 32 ACP, 380 ACP, 9mm, and 45 ACP. I have not heard of a "roll crimp measurement" and just go by eye.

[pworley1]

The Lyman manual gives .473, so that is what I try to get.

[Mal Paso]

Diameter will vary with brass and bullets. You should just remove the flair. The mouth of the case should be the same diameter as just below the mouth.

[billmc2]

The Lyman manual gives .473, so that is what I try to get.

Thank You for that. I just checked my 3rd Edition Lyman Pistol & Revolver Handbook. In the drawing for the cartridge dimensions, I am now seeing a smaller dimension given for the case mouth compared to the other end of the case. I hadn't picked up on that before. A quick look shows that it is only the taper crimp cartridges have this dimension shown, not the roll crimp ones.

[Electrod47]

I do not measure any semi-auto case crimp. Actually I do not "crimp" any either. I just deflare with a deflaring die (aka taper crimp die) and plunk test. Bullets are held in place on semi-auto cartridges by neck tension, not a crimp. Works for my 32 ACP, 380 ACP, 9mm, and 45 ACP. I have not heard of a "roll crimp measurement" and just go by eye.

Exactly,,

[gwpercle]

Back in 1967 we didn't have fancy measuring devices ... a wooden carpenters zig-zag measure that my dad didn't let us touch , a 12 inch ruler and a yard stick .
To check the crimp on 45 acp you pressed the boolit against the edge of you bench and if the boolit slid deeper into the case ... you needed more crimp ...
You kept adjusting crimp untill the boolit held firmly when pressed against the edge of the bench .
That ...pressing against the edge of your bench ... works for all calibers and all crimps and you don't need calipers or book dimensions .
It's called " Old School Reloading "
Gary

[billmc2]

Back in 1967 we didn't have fancy measuring devices ... a wooden carpenters zig-zag measure that my dad didn't let us touch ,
Gary
My father had one of those but I don't recall any restrictions being put on it.

[Elpatoloco]

Back in 1967 we didn't have fancy measuring devices ... a wooden carpenters zig-zag measure that my dad didn't let us touch , a 12 inch ruler and a yard stick .
To check the crimp on 45 acp you pressed the boolit against the edge of you bench and if the boolit slid deeper into the case ... you needed more crimp ...
You kept adjusting crimp untill the boolit held firmly when pressed against the edge of the bench .
That ...pressing against the edge of your bench ... works for all calibers and all crimps and you don't need calipers or book dimensions .
It's called " Old School Reloading "
Gary

This is how I do my taper crimp cases. I have stong hands and my loading bench has dents all over it from doing as described. Ive never had any issue and I wasn't born until '73

[cwlongshot]

Diameter will vary with brass and bullets. You should just remove the flair. The mouth of the case should be the same diameter as just below the mouth.

^^This

LONG TIME reloader here and as much as I respect Brian Pearse this measuring a crimp is just nonsense. Mai has told you why!
Know that every manual made shows a correct crimp. Knowledge of the process tells you style of crimp that may be needed.

As mentioned just remove the flair on a case that head spaces off its mouth. You can see in pictures in those manuals whats too much or not enough and read why.

Not putting you down or ridiculing. I know we have many new loaders coming for information. But that information is provided to and for you in spades in the reloading manuals you need to own.

[Mk42gunner]

Yet another way to set your crimp is what we did in the late 1980's: use a factory round to set your crimp die against. Then do the push against the bench trick. No measurements needed.

It usually worked, especially for .45 ACP which just may be the easiest round to load.

Robert

[44MAG#1]

I crimp the way I want too. It works for me. So to me it is good to go. I Used to just straighten out the flare but now I crimp pretty stiff. Generally .468 inch or so on bullets sizes .452 inch. It works for me. I have no problems so I don't have to worry about what others do. Each needs to do what WORKS FOR THEM and not worry what others think.
I have been loading for over 50 years
Too many people read to many articles. Occam's Razor is the name of the game.
Load and go forth and shoot.

[charlie b]

Yep, crimp enough to hold the bullet. Then do a plunk test.

If you want to measure, the cartridge drawings show a neck dia of 0.473.

If you are going to crimp or remove the flare from the case mouth then I strongly recommend a taper crimp die. It is tough to get a roll crimp to be 'just right'. I reserve roll crimps for rimmed cartridges.

[mehavey]

Well.... I don't 'crimp' so much as ensure the seating die de-flares the mouth to what you see below:
306096

.... and yes, I do measure the mouth at the start of the first couple of bullets in a loading session
... w/ a caliper
.. and plunk it.
8-)




postscript: I've both separately* "crimped" and simul-"crimped" to set the mouth. Finally just settled on the latter.
* (Redding profile when I was experimenting)
306098

[Hossfly]

this is what I’ve done with 45 acp.
#1 Crimp flare down
#2 measure coal
#3 press down on scale to 50# bathroom scale fine
#4 remeasure coal if no reduction in coal good to go
#5 plunk test in barrel going to shoot in.

[billmc2]

Thanks guys. Not having a teacher I'm reading the books and trying to go from there. I've had a question in the back of my head, wondering if I'm doing it correctly. When I came across this article, it was the first time I had seen a reference to a measurement of the case mouth. When pworley1 pointed me to the drawing I finally saw it. Prior, that particular measurement had been lost to me within the clutter of all the other numbers. I had never noticed a difference between the case head and the case mouth. I haven't tried loading the 45 ACP yet but when I do, I'll now have a means of determining if I'm doing it correctly or not. (That particular article was a squirrel running in front of me while searching for something else.)

[David2011]

The picture that pworley1 posted is an excellent guide. Since most of my semi-auto handloads have been for competition shooting I value measuring and consistency. I set the taper crimp die by measuring just behind the case mouth to avoid any burr on the mouth affecting the measurement. There is nothing wrong with measuring to verify that the taper crimp die has done its job. If you're only loading for a single gun then a plunk test in your barrel is adequate. If loading the same cartridge for multiple firearms then it would be a good idea to use a case gauge for the plunk testing. A case gauge is manufactured to the minimum SAAMI chamber size specs so a reload that passes the case gauge test should load without issue in any gun using that cartridge.

[44MAG#1]

Remember if it works for you, you are doing alright.
Let the target be the Arbiter in what you are doing.
BTW. It goes without saying, because I hope everyone knows EVERYTHING should be done with safety in mind , and uses safe loads. Also everything done with consistency.
The target is STILL THE ARBITER in the case brought before it.
The case being the Shooter, Load and gun.

[dogdoc]

Patrick Sweeneys book, Handloading for Handgunners has some of those specifications

[Soundguy]

Yesterday I was reading an article in Handloader magazine written by Brian Pearce. The article was titled Loading The .45 ACP. (https://www.handloadermagazine.com/loading-the-45-acp-pet-loads)

In the article he says
"The crimp should measure .470 inch, which can be measured at the case mouth using blade calipers."

I have wondered how do I know if I've gotten the crimp correct and here he gives me a measurement I can use to verify what I have done. I have looked in several of the reloading manuals I have and I do not find a reference like this in any of them. (I have not yet tried loading the .45 ACP, I do have the dies and components to do so, I just haven't gotten around to it.) I assume that if this information is available for one cartridge then it must be available for the others. Where do I get information like this? In this case he is dealing with a taper crimp is there something similar for roll crimps?

Some manuals DO give you case dimensions.. and you can ALWAYS get them from SAAMI. However.. it's generally easier to 'test' than to measure a case mouth with a caliper.. It needs to pass 2 tests.. or 3, depending on how you count.

1, there has to be enough (taper) crimp to keep the bullet from moving in the case. Rule of thumb on that has always been to push your completed case into your wood reloading bench, nose first, as hard as you can.. and if it doesn't move..it's fine.

2, ?(3) The case flare has to be closed so that the cartridge will chamber *correctly*.. not too much.. or the case mouth will not headspace correctly and let the cartridge fall into the chamber too deep.. likely resulting in light primer strikes ( unless the extractor claw helps out an old friend ).. but yet closed enough that it will fit.

Some like to use a barrel as a test gauge.. I instead use a lyman test block. I make a few.. push test them.. then plunk test them. If they pass those... I have never had a failure to fire.

[bedbugbilly]

On my semi auto loadings (.380, 9mm and when I was loading 45 cap) I might measure the case mouth when/if setting up the dies, but then I let a cartridge gauge and cycling a couple of dummy rounds in the pistol tell me if everything is kosher. I seat and crimp in separate operations on all of the cartridges I load - pistol or rifle - and on the semi-auto cartridges, ironing out any flare with the taper crimp or a Lee FCD has always worked well and again, if my dummy rounds ass the plunk test and hand cycle - good to go. I still random test with a cartridge gauge during loading. Everyone might do things a little different but if they work and go bang, you're doing something right. I do random check COAL when loading up a batch, but have never had an issue.

One also has to remember that when using range brass with mixed headstamps - which is what many folks use - not all brass is created equal. Case length can vary as well s case wall thickness - which can make your car mouth measurements + or - a tad bit.

[Walks]

Too many over think this process. I have 3 different loads for .45ACP, there is a dummy round for each bullet type in the die box. I just set the C.O.A.L. by the dummy. The taper crimp die hasn't been touched in over 30yrs.
Not something I think about any more.

[charlie b]

I did that for a long time as well. Then I ejected a couple rounds and noticed the bullet sitting deeper in the case. Turns out a tumble lubed bullet was 'slick' and could be pushed deeper into a sized case. Went to a slight crimp after that. Doesn't take much crimp to work. And on a progressive just means I am using all the spaces on the turret :)

[gwpercle]

My father had one of those but I don't recall any restrictions being put on it.

Me and little brother would play with them ... they don't hold up well in a sword fight ...after we broke the second one ... that was it ... we both got to see his belt and we could no longer touch the zig-zag measure . Mom's yardstick made a much better sword !
Gary

[WRideout]

I was having trouble with the 45 ACP having boolits slide deeper into the case. I went ahead and ordered a taper crimp die, and now seat and crimp in two steps. Problem solved.

Wayne

[georgerkahn]

Re crimping I noted, years back, the very different amount of crimp being applied as I loaded a box of 50 rounds of what I hoped to be same, identical ammo. Doing a post mortum ;), I first noted that the (mostly range pickup) brass was not all the same length. Using the RCBS crimp die, case length grossly affects amount of crimp. Secondly, the brand of brass seemed to have an affect, albeit lesser than case length, as well.
To my way of thinking and OCD attempts to produce the best cartridges, I do believe that in addition to just keeping the bullet from moving from prior shot recoil, the "amount of grip" also affects potential accuracy. E.g., I desire the SAME amount of tension -- or, as close to this as I might get -- on each case.
I OCD-ly used my L E Wilson case trimmer to get each case alllmost identical in length; time consuming; so, I switched crimping to a Lee Factory crimp die. However, there's still a variation in case length, and we all know that inner space (bullet bottom to case) affects pressure. (Which gives me another excuse :) for my lousy shooting performance)
Seriously, keeping the bullet from any movement in its case is my #1 objective!

Oh -- re the side-track re folding zig-zag rulers -- I have three or four of these and do use them regularly. The bend/non 100% straightness of a metal tape affects potential measuring accuracy as well as that blankety-blank hook on tape's end "ALWAYS" falling off... :)

geo

[justindad]

Diameter will vary with brass and bullets.

Another vote for ^^^.
*
I will cycle one round through the action three times, and then remeasure OACL. Ideally the round will not shorten, but I allow about 0.002” with .357SIG ammo.

[billmc2]

Me and little brother would play with them ... they don't hold up well in a sword fight ...after we broke the second one ... that was it ... we both got to see his belt and we could no longer touch the zig-zag measure . Mom's yardstick made a much better sword !
Gary

Right off the bat I can see where the difference between your and my restrictions come from. I'm the only boy. I never tried but I'm pretty sure I wouldn't have been able to engage my sisters in sword fighting. I do agree that a yard stick would be a much better choice of weapon.

[billmc2]

This has been an interesting discussion for me but I guess I left some things out. I did mention that I'm not loading 45 ACP (yet).

Most of you guys have been at this much, much longer than I. I only began hand loading towards the beginning of 2022. I think it was around July 2022 when I got my first mold and began casting. I do not have anyone teaching me how to do this (I have had a couple of PM conversations with guys that have been very helpful). Where some of you have had your crimping die rusted in place, I on the other hand, had (have) no way of knowing if what I am doing is correct or not, without some kind of reference to compare with. Of the rimmless cases I've loaded so far, I haven't had issues (that I know of) yet, my most recent trouble has been with the 32 H&R Mag. Even using the Lee Factory Crimp die wasn't working for me. Using the crimp measurement of the 32 ACP (in other words the diameter of the case where the taper crimp is in the 32 ACP) and applying that to the 32 Mag, I have solved my problems. My 32 Mag cartridges would not fit into every chamber without a little extra effort (they would fit some but not all). I also had trouble getting them to fit into my Wilson case gauge.

I assume the "plunk" test is dropping a cartridge into the chamber and the cartridge seats fully into the chamber without any extra effort. Now I can say that my 32 Mag cartridges pass the plunk test in both the chambers in the revolver and the case gauge and I feel I am doing it correctly. I doubt very much that I'll be able to come back in 30 years and say that my crimp die has rusted in place because it never needed any more adjustment. Not because it didn't need adjustment but because I'm old enough that I doubt I'll still be around 30 years from now.

[44MAG#1]

This has been an interesting discussion for me but I guess I left some things out. I did mention that I'm not loading 45 ACP (yet).

Most of you guys have been at this much, much longer than I. I only began hand loading towards the beginning of 2022. I think it was around July 2022 when I got my first mold and began casting. I do not have anyone teaching me how to do this (I have had a couple of PM conversations with guys that have been very helpful). Where some of you have had your crimping die rusted in place, I on the other hand, had (have) no way of knowing if what I am doing is correct or not, without some kind of reference to compare with. Of the rimmless cases I've loaded so far, I haven't had issues (that I know of) yet, my most recent trouble has been with the 32 H&R Mag. Even using the Lee Factory Crimp die wasn't working for me. Using the crimp measurement of the 32 ACP (in other words the diameter of the case where the taper crimp is in the 32 ACP) and applying that to the 32 Mag, I have solved my problems. My 32 Mag cartridges would not fit into every chamber without a little extra effort (they would fit some but not all). I also had trouble getting them to fit into my Wilson case gauge.

I assume the "plunk" test is dropping a cartridge into the chamber and the cartridge seats fully into the chamber without any extra effort. Now I can say that my 32 Mag cartridges pass the plunk test in both the chambers in the revolver and the case gauge and I feel I am doing it correctly. I doubt very much that I'll be able to come back in 30 years and say that my crimp die has rusted in place because it never needed any more adjustment. Not because it didn't need adjustment but because I'm old enough that I doubt I'll still be around 30 years from now.

You let the mechanical performance of the cartridge tell you and then the target is the final Arbiter of all of it.
If you have good mechanical performance and then the target gives the final approval. You are good to go.

[popper]

Taper crimp only - pull the press handle till it feels hard. no measuring! I don't trim pistol brass and unless you do or measure every one, you will never get them all the same. Dito with rifle FCD.