10mm Is Killing Me!

[mobocracy]

First there was the sizing die that got loose, requiring pulling 500 bullets. One Lee pot-metal press and a collet puller later, I thought I was back in action. Until today! I went to the range to shoot some of my 10mm ammo yesterday and I always shoot a cylinder and/or a magazine of ammo and then check the last unfired round to make sure I have no obvious setback or pull-out problems.

I did! My 135gr loads were really pulling out (when shooting my 610), the 180s a little less so. Both rounds also more dangerously set back in the magazine of my Kimber. Aww, crap I thought, not enough crimp. I came back, checked for loose dies (none, thankfully) and other obvious problems. I figured well, maybe it was just not enough crimp. I tightened down my crimp die by 1/6th of a turn, re-crimped a dozen rounds and then went another 1/6th tighter and crimped another 12, labeling both.

Went to the range today and fired some known ammo with a couple of the recrimped rounds -- oh no! -- same problem as yesterday, to about the same degree. I pulled some of the bullets when I got home and noticed that they looked way overcrimped. I could feel a dent in the jackets where they had been crimped. They measured nearly .005 under what new bullets were.

I could swear I've read that overcrimping taper-crimp cases actually makes the bullets looser, not tighter. Is this true? In this case, I'm screwed since it appears I've pretty much trashed about a case of 180gr JHPs and about 250 135gr JHPs.

These cases have all been fired before, around 3-5 times, mostly on the high end of Alliant's published load data (~8.5gr Power Pistol). Can cases, even if not split, lose their "grip" over time?

What's so frustrating about this is that a test batch of about 100 rounds worked fine, and so have around 3000 .41 Mag and .44 Mag rounds loaded on this press, as well as 3-4k 10mm rounds loaded on my old SDB. I *thought* I knew what was doing...

Ahh humility -- between my collet puller, my time and the trashed bullets, I could have been shooting factory ammo..

[GentlemanJim]

The only time I have seen a problem like this (bullets slipping back) .

It was the sizing die not going down far enough on the case,leaving the bottom of the case too large.

I hope that's all it is

Jim

[EricW]

You're overcrimping. Only crimp enough to remove the belling and no more. There should be no groove embedded in the bullet from where you smashed the brass into it.

If the bullets are creeping out under recoil, consider buying an undersized die. Or, you may just have a die that's got an oversize carbide sizing ring - it happens.

[shred]

Crimping rarely solves setback problems and isn't the right way to do it anyway (except maybe for the roundy-roundy guns). The answer is a tighter sizing die and/or less expanding.

[smokshwn]

did these bullets happen to be from the batch that were previously pulled? If so they may already be undersized a smidge causing the setback issue

[yoshidaex]

+1 on the undersize die advice. I don't reload 10mm but i use a EGW "U" die for my 40 s&w rounds and no problems so far. Though a friend just recently bought a U die from EGW and it doesn't look like it sizes all the way down (i'm wondering if he has it adjusted correctly?). or a possible design change to make it work better in progressive machines? who knows...

sorry for the slight thread drift...

[Lee Bell]

I'm a bit surprised at the problem. I reload 10mm on my Dillon 550. I use 180 grain Zero JHP bullets, Winchester primers and 5.8 grains of Bullseye yielding a MV of around 1,040 fps and a PF around 187. I've not had a single setback problem, ever. For that matter, I haven't had them with anything else I reload.

There are only a couple of things I can suggest as the source of the problem:

1. I've been told that old brass sometimes fails to grip the bullet well, allowing what you've experienced. Of course, this was told to me by someone trying to explain why the bullets he sold to someone else had pushed into the cases, so take it for what it's worth. In 10mm, I've never had old brass. It's not like you can pick it up all over the place like you could back when people still thought it was a good caliber . . . as I still do.

2. I've read a lot about the effect Glocks have on brass, expanding it in ways that a standard Dillon sizing die does not correct. If you're shooting a Glock, or getting brass from those that do, perhaps that's part of the problem. If so, the standard answer seems to be an undersized sizing die.

Good luck in identifying and addressing the problem. I feel your pain, well, I soon will. I've got 200 .45 rounds I loaded hotter than I intended to take apart myself. Ain't reloading wonderful?

Lee

[mobocracy]

Thanks for all the help and suggestions.

My thoughts are that I've pretty much ruined the bullets by overcrimping them. Some might be salvageable, but that's a different project.

I think I ended up overcrimping them because a couple of years ago when I got my Glock 29, I was having just awful feed and ejection problems. I measured the case mouth of a factory R-P round and found my loads were larger by .002-3. A slight tightening of the crimp die on my SDB got my case mouth to match the R-Ps and my Glock jamming went away.

I guess when I set 10mm up on my 650, I got too aggressive on crimping.

What I'm going to do:

Double-check all my dies, especially the crimp die (which will get a like-it-was-just-bought setup). Then I'm gonna take some brand-new brass and bullets and work up a half-dozen or so cartridges and see what these do. If that works, I'll reload some of my used brass with new bullets. If that works, I'll buy another case of bullets and load out the rest of my brass (after taking apart 1200 rounds...ugh).

The acid test will be what happens with new brass and bullets. If I still have issues, it may actually by my size die (anyone have any issues with Redding Pro TiC size dies?). I might just splurge and buy a set of Dillon dies.

The good news? When I get to reloading my cases, at least I won't have to use primer tubes -- they're already primed!

If all this fails, maybe I'll just buy an airsoft Glock and throw empty 10mm cases to pretend they're ejecting.

[ihatepickles]

Taper crimping is misunderstood. Roll crimping has a direct correlation to preventing bullet setback, but taper crimping is almost unrelated. Brian Enos made a good post that I keep bookmarked. Taper crimping is just a step needed to repair the case after the bullet is seated.

In a taper crimped autoloader, most bullet setback issues are related to sizing the case and not the crimp. If you over-crimp the case becomes distorted and the bullet is actually looser in the case mouth. If you've reloaded the brass 4+ times it may be getting a bit more brittle and the sizing die isn't able to really do it's job correctly. .45 brass lasts a long time (somesay they've gotten more than 15 reloads from .45) but 10mm brass is likely taking a much harder beating and 4 cycles of reloading is probably the end of the line for the brass.

I think your bullets may be damaged, but it's possible your 10mm brass has been reloaded too much and it's no longer sizing enough to hold the bullet. A undersize die may help, but if the root cause is overworked and brittle brass then you're borrowing trouble when you keep using the brass. Get some new brass and put it through the sizer, do the same with your older brass. If the two vintages are coming out of the sizing process with different external dimensions then you have evidence that it's time to pitch the older brass.

Edited January 16, 2007 by ihatepickles

[Patrick Sweeney]

The brass may be too old. The bullets may have been knarfed by now to the point of non-salvagability. The sizer may not be sizing your brass down correctly. All of these things may be parts of the problem.

But your big problem is your belling tube. It is too large. Pull it out and measure it. For a 10mm, using .400" bullets, you should have a tube no larger than .396" For a hot load round like the 10mm, .394" might ber even better.

If you do not see the "coke bottle" effect of a seated bulelt in your case, you are belling too much, reducing neck tension. Neck tension is what keeps the bullet in place, not crimp.

You should also polish it while you're at it. A rough belling tube increases friction, increasing the work you have to do and the vibration you create in working the press.

[Lee Bell]

If all this fails, maybe I'll just buy an airsoft Glock and throw empty 10mm cases to pretend they're ejecting.

Please, throw them my way. I've had a couple thousand Starline cases on order for more than a month now. The source, who offered the best, but still not good, deal I could find, is out of stock. That figures.

10 mm is so hard to come by that I just bought a new Kimber Gold Match II in .40. Those I have lots of. Where are you getting your cases?

Lee

[mobocracy]

Please, throw them my way. I've had a couple thousand Starline cases on order for more than a month now. The source, who offered the best, but still not good, deal I could find, is out of stock. That figures.

10 mm is so hard to come by that I just bought a new Kimber Gold Match II in .40. Those I have lots of. Where are you getting your cases?

I bought around 200 Winchester yellow brass cases with my Dillon SDB about three years ago. After a range trip and the daunting task of finding yellow 10mm cases in a sea of .40s, I ordered a case of Starline Nickel 10mm cases from Blue Star Cartridge & Brass. When Midway began carrying nickel Starline about a year and a half ago or so, I picked up another half case from them.

I've also picked up 3-400 once-fired R-P nickel cases from my range; the owner knows I reload 10mm and doesn't know anyone else who does, so when he sorts fired brass he will pick out the nickel cases for me.

I just checked Midway and they seem to have Starline Nickel and W-W available. Based on some previous messages, *I* may be in the market for another case of fresh brass, too, if this current stuff proves worn out and unable to retain bullets.

[mobocracy]

I think I'm back in business!

I totally re-adjusted everything, including a from scratch (if that makes sense) setup of the crimp die, or as Mr. Enos more correctly calls it, the case-bell-removing die.

Using new bullets, I loaded 20 with new brass, and 10 each with used Starline and R-P brass from the "bad" lot, and they all worked as desired -- no pullouts in my 610 or setbacks in my Kimber STII.

One final question, though. During the run of "bad" bullets I had a VERY slight belling adjustment setup, so slight that there was pretty much no perceptable belling. When I re-adjusted everything, I did increase the case bell a smidgen.

Is there such a thing as too little belling, even if you're not shaving the jacket? As much as I'm pretty sure I just had the crimp die way too tight, I started wondering if inadequate belling could somehow cause the case seating area to get loosened/strecthed/etc.

Thanks again for all the great info and advice!

[benos]

Is there such a thing as too little belling, even if you're not shaving the jacket? As much as I'm pretty sure I just had the crimp die way too tight, I started wondering if inadequate belling could somehow cause the case seating area to get loosened/strecthed/etc.

If you're not shaving jacketing, belling "too little" won't cause any other problems.

be

[Lee Bell]

I think I'm back in business! I totally re-adjusted everything, including a from scratch (if that makes sense) setup of the crimp die, or as Mr. Enos more correctly calls it, the case-bell-removing die. Using new bullets, I loaded 20 with new brass, and 10 each with used Starline and R-P brass from the "bad" lot, and they all worked as desired -- no pullouts in my 610 or setbacks in my Kimber STII.

Congratulations.

One final question, though. During the run of "bad" bullets I had a VERY slight belling adjustment setup, so slight that there was pretty much no perceptable belling. When I re-adjusted everything, I did increase the case bell a smidgen. Is there such a thing as too little belling, even if you're not shaving the jacket? As much as I'm pretty sure I just had the crimp die way too tight, I started wondering if inadequate belling could somehow cause the case seating area to get loosened/strecthed/etc.

As far as I know, the only adverse effect of too little belling is that it's hard to get the bullet to sit on the case long enough for the seating die to seat it. I've had a couple bullets fall over, destroying the bullet and the case when the seating die came down on them. Other than that, the less belling, the better. Stretching and crimping the case mouth more than necessary shortens the reloading life of cases.

Glad you succeeded.

Lee