taper crimping

[oscar243]

I reload .45 ACP and .40 S&W. I have a taper crimp but still encountering loose bullets in the case. At what stage in the reloading process is the taper crimp used? I'm doing something wrong here.

 

[Cholo]

Taper crimp last:

45ACP .470

40 S&W .420

A little less can do, not more.

 

[oscar243]

Thank you Cholo.

 

[Cholo]

You're welcome. It's nice to see someone who hasn't the disdain for the .40 that I really like.

 

[gster]

As said, it's the last step. I just have to ask though. Have you ever read a reloading manual?

 

[Chuck 100 yd]

+1 on all replies above. If you are shooting cast bullets,and over crimp, the brass will spring back a tiny bit but the lead will not, leaving the bullet loose. As said above, a little is better than too much.

 

[DGW1949]

As said, it's the last step. I just have to ask though. Have you ever read a reloading manual?

Call me old school, but I've reloaded a gazillion .45ACP's using nothing more than a "regular" set of RCBS carbide dies. With those, whatever "crimp" that may or may not be getting added is applied in conjunction with seating the bullet....no separate die needed, be it as a "last step" or otherwise.
That's basically how it was done for years....way before the " separate and final step taper-crimp die" came along as a cure for ills which would be better addressed by utilizing the proper expander size to start with.

Maybe your "manuals" talk about dedicated taper crimp dies....dunno...but none of mine do. Maybe like me, they predate the use of such things.
On the other hand, all dies DO still come with instructions though....

Just sayin'.

DGW

 

[WIL TERRY]

TAPER CRIMPING [ or Roll crimping for that matter..] has NOTHING to do with TIGHT bullet seat. You FL sizer and the expander plug have EVERYTHING to do with tight bullet seat. You are looking in the wrong place. The expander plug should be .002"-.004"O.D. under projectile size, and this assumes your FL size die is correct and you set it correctly.
And it goes...

 

[mikld]

Agree with Mr. Terry. Neck tension holds the bullet in place. Odd as it may sound, over crimping will loosen a bullet in the case. Over crimping also can bulge a case. So, I K.I.S.S. and do not crimp my semi-auto ammo, I merely use a taper crimp die to remove any flare from the case. This has worked for me, along with the "plunk test" for a few thousand rounds in 45 ACP and as many 9mms...

 

[loaded round]

It may be repetitious on my part, but restating that all quality reloading manuals plus the die manufacturers themselves have complete instructions explaining step by step on how to to set the seating/ crimp die to get a secure crimp. In a three die set, crimping can either be tapered or folded depending on type of case (revolver or semi-auto).

 

[Rodfac]

Cholo You posted the following in regards to taper crimping...I'm curious as to how and where you get the measurement. Are you using a pr. of calipers or a mic across the very mouth of the seated and crimped case? I've taper crimped since before there were taper crimp dies unless you special ordered them. I used a steel sizing die to remove the flare (still do in one caliber in fact). It provides a slight taper crimp, I've never measured my taper crimp with either type die, going by feel instead which has worked well to date (50+ yrs now). Rod

45ACP .470
40 S&W .420
A little less can do, not more.

 

[PO2Hammer]

I have a taper crimp but still encountering loose bullets in the case.

Sounds like you might be using too much flare/expansion by setting your expander die too deep.

If the case is over expanded the brass doesn't get any grip on the bullet as it's being seated. It's that grip, or bullet tension, that puts most of the hold on the bullet and prevents bullets being set back into the case during feeding.

Back off your expander die off until you can barely seat a bullet in the case mouth. (not an easy fit, but just barely) Then adjust your taper crimp die to crimp the case mouth about .002" less than the diameter of the case measured over the bullet.

 

[Biggfoot44]

Even the old school 3 die sets had taper ( or roll ) crimp. And it was still applied in the "last step", albeit more than one prosess was taking place during the said Last Step.

The other, other thing is despite the functions being combined on the same physical die, it was (is) possable to perform the steps separately. Back the die body out of the press, and lower the seater to seat the bullet before the case contacts the crimping shoulder, thereby the bullet is seated without any crimp. Then screw back in the die body, but raise the seater so it doesn't contact the bullet even when shellholder at the top.

Yup, a lot more hassle. *Most-* of the time the seat & crimp in one step works acceptably, but sometimes for specigic bullet/ brass-/ load, seperate is needed.

As to the OP; IF his crimp die is in spec, and the brass isn't very thin necked, and the bullets aren't undersized, the most likely suspect is the case expander. Specifically being too large, leaving the sized neck ID too large, thereby giving insufficient neck tension.

 

[Imissedagain]

Now that you understand why the taper crimp is used and that seating and crimping are best completed separately you're good to go.... that is if your sizing die and flairing die are setup correctly.
Based on the OPs first post I'll add..... make sure your powder charge ain't doubled etc etc etc.
Stay safe.
Have fun.
Read often thy manuals.

 

[Cholo]

Rodfac, I just now saw your response. I learned it the hard way. Back around '97 or so I began reloading CF semi autos, the .40 S&W was the 1st. I swagged it and had multiple failures to go fully into battery by 1/16" or so. I came home and measured the case mouths of my factory .40 ammo. I was .001-.002 too large I tightened them up to .420 and life was good. I then started loading the .45 ACP. I measured factory .45 ACP's and came up with .470. I never got a failure to go fully into battery.

I then got a great idea. I bought the Dillon gauges. If they dropped right in they were good to go, though I already knew that by measuring factory ammo. I don't go by dropping it into the barrel to see if all's right. The factory ammo measurement has it right for all normal factory semi autos.

 

[Rick Courtright]

The factory ammo measurement has it right for all normal factory semi autos.

Hi,



I started reloading shortly after turning 15, and went to work at a trap & skeet range at age 16. Being young, impressionable and quite full of the stories I'd read, I asked my boss, a former Winchester pro, about being able to reload better ammo than the factory makes. He laughed, and told me: "Son, the day you can load better ammo than the factory does now, you'd better start your own company, cuz there will be enough demand for it you'll be a millionaire the first week!"

Over the next half century, I've come to the conclusion that folks who do the same thing millions of times a day that their company's done for maybe 100 years or so might just know a thing or two (I'm not the fastest learner, ya know!) So I try my best to duplicate what they do first, before trying to reinvent the wheel for myself. It's not the worst idea I've ever had...

Rick C

 

[7p's]

What I've found, at least with the handgun cartridges I reload for, is I get the greatest case tension by polishing the expander plug down, so nothing touches the case except the bell portion of the expander plug/stem.

Some cases may give the look of a snake swallowing a small object but I've never noticed a decrease in accuracy and never experience bullet set-back in heavy recoiling handguns - of course, I also use the proper crimp using the Redding profile crimp die - just my preference.

For the 45 ACP I measured the factory crimp of the Federal Match back in the day and their crimp was 0.472 but I found I could reload for my match grade 1911 using bullseye and then later on VV 310 and the 185 grain bullet that would shoot tighter groups using a 0.468 taper crimp than Federal Match. That is a rarity but my 1911 just doesn't play well with Federal Match - close but no cigar. Never found the crimp from 0.468 to 0.472 to make a difference in accuracy but I like the physical feel of the 0.468 over the others.

 

[mikld]

For my info only; for the "old" reloaders who started before taper crimp dies were available, did you or anyone else roll crimp the 45 ACP rounds? I've only been reloading revolver ammo since 1969 and semi auto ammo since 1989 and every die set I've purchased has the correct crimp included in the seating die, ie., taper for semi-autos and roll for revolvers. About when did the crimps become standard?

 

[DGW1949]

For my info only; for the "old" reloaders who started before taper crimp dies were available, did you or anyone else roll crimp the 45 ACP rounds? I've only been reloading revolver ammo since 1969 and semi auto ammo since 1989 and every die set I've purchased has the correct crimp included in the seating die, ie., taper for semi-autos and roll for revolvers. About when did the crimps become standard?

As I recall, I first started loading .45ACP around 1974.
From then through today, I've never applied a "roll crimp" to any type of 45ACP round, be it jacketed or lead....nor have I known anyone else who did.

And yeah, me thinks that you are right relative to "every die set I've purchased has the correct crimp included in the seating die"....Leastways, that's the way all of my RCBS dies are made.
There are however, exceptions to the "taper for semi-autos and roll for revolvers" rule, meaning that some semi-auto rounds were designed from the get-go to headspace on a rim, not the case mouth like the .45ACP. Off the top of my head, that would include the .32ACP, .38ACP, and the .38ACP+P (AKA .38-Super), but I'm sure there's been others, along with a couple of bottle neck pistol cartridges which also get a roll crimp.

At any rate, your premise is correct: The guys who make dies perty-much know what they're doing relative to "what crimp for what cartridge".

Hope this helped.

DGW