I’m not but be advised if you are using nickel plated it won’t take very many to dull the cutting blade.

 

Good point!

 

No. I've never trimmed an auto loader case. With a glock, the extractor determines headspace anyway, so it would be a moot point.

 

No. I've never trimmed an auto loader case. With a Glock, the extractor determines headspace anyway, so it would be a moot point.

:agree::dancingbanana::broccoli::broccoli::devildance::goodpost::jumpingjacks:
If it ain't broke, don't fix it.

 

Trimming straight walled cases for consistent crimp in a Glock is somewhat justified, but for head spacing is a misconceived notion.

 

What about an XDm?

 

Take a micrometer reading on the depth of your chamber, then measure case length. Normally, straight-walled cases will shrink after firing, so if trimmed to head space on casing they will only head space on case mouth once. Note: SAAMI spec is minimum .992"+.012"; most new cases are only .987" and won't head space on case mouth.

 

Interesting. You learn something every day. Thanks!

 

GJ makes a good point. I've not found that 10mm cases grow with successive firings. In fact they shrink over time. So there's no way to maintain a consistent COL via trimming.

If trimming did make a difference in ammo consistency, my shooting ability couldn't exploit it anyway.

 

So, it sounds like the only advantage might be crimp consistency.

 

Correct.
However, at least with my L.E.Wilson 10mm case trimmer, trimming straight-wall cases is slow, tedious, and requires a press, unlike bottle neck cases.

With jacketed bullets, little or no crimp is needed, some like zero-crimp and rely solely on neck tension, so very little advantage if any. With plated bullets, again, the less taper crimp the better since the thin platting is easily damaged and accuracy suffers. Also, if the goal is for the cartridge to headspace on the case mouth, most reload manuals recommend very little or no crimp. Consequently, for most of my auto-loader reloading, little or no crimp is set on the taper crimp die.

With HC Lead, a consistent .002" taper crimp seems to work well, but I'm still in the learning stages on that, and with cannelure bullets (revolver) a uniform roll crimp is advantageous.

Rather than trim all my cases when I feel a uniform crimp is need, I just measure and sort the cases, select the batch of cases I want, and then re-set my crimp die for that session of loading. An extra 30 minutes of sorting and die reset, but beats a couple of hours of case trimming.

PS - The Wilson 10mm case trimmer die makes an excellent, but expensive, weight for keeping my place open in the reloading manual.

 

gj: a bit off topic: what about trimming revolver cases? I recently began loading 44 mag. I have & love the Wilson trimmer when needed. And I have a couple of their “paper weights”.

 

what about trimming revolver cases? I recently began loading 44 mag.

A revo cartridge headspaces off the rim, so trimming not critical for that purpose. But trimming to ensure a good crimp, in terms of location on bullet, and therefore pressure, is wise if needed. A high, hard crimp above the cannelure could damage the bullet and, more importantly, increase pressure. Too little crimp may allow a bullet to jump (magnum loads) and potentially lock-up the cylinder.

Sorting by headstamp should reduce the case length differences and, therefore, crimp variability. But generally speaking, little need for trimming revo brass.

 

^^^^
This

 

No. I've never trimmed an auto loader case. With a glock, the extractor determines headspace anyway, so it would be a moot point.

Exactly. factory ammo and cases are all slightly different lengths but they headspace on the extractor claw. That's why you can shoot 40 S&W in a 10mm.

The only cases I've ever had to trim were 30 carbine which I shot out of a Ruger Blackhawk that would stretch after about 4 or 5 full power loadings and would stick out of the back of the cylinder so much that the cylinder would not rotate.

Stretching on the 30 carbine case was especially bad because it's a high pressure round and it's long for caliber and straightwalled. I doubt that the 10mm case stretches much after 4 or 5 reloads even at maximum pressure

 

Thanks! I was taught to trim the 30 carbine for the M1. I still trim but mostly use them in a AMT Automag.

 

I know this is an old thread but, had to chime in. I have been trimming 10 mm brass for a decade. Started with the old Lee setup using a drill mounted on a vise. Then when the Lee Quick Trim dies came out I converted my most used calibers to that setup. The brass does grow ! I at 0.992" in trim it back to 0.987". It appears to keep the rounds more consistent. Also feeding issues have occurred with long cases in my EAA Witness but not in the G20.

 

Interesting observation. I have several thousand pieces of 10mm brass and tens of thousands of reloads. I have never measured a case that was longer than max. In the early days I was really OCD and measured each sized case. The first several thousand were done this way. I observed them shrinking below mins eventually and I used to cull them. And to be clear, the measurements were after sizing.

Again, interesting that your observations were 180.

 

Taterhead , the rounds were shot from an EAA Witness. Hot rounds stretched the brass. Even new Starline on the first firing. The Witness is more like a Lamborghini and the G20 is more like a Ram pickup. The G20 eats everything but the Witness has a Max pressure then it won't cycle.

 

Taterhead , the rounds were shot from an EAA Witness. Hot rounds stretched the brass. Even new Starline on the first firing. The Witness is more like a Lamborghini and the G20 is more like a Ram pickup. The G20 eats everything but the Witness has a Max pressure then it won't cycle.

Sure, but I have never seen lengthening of a straight wall case with subsequent reloads loads in any auto-loading handgun. I'm not saying that I disagree, just not in my empirical universe.

So your observations are interesting to me.

FYI, I hear the Witness is a nice shooter.

 

Love the Witness, great shooter. It has a tight chamber. If a round is too long it will not chamber ! I am pretty OCD on the 10mm handloads. Only do hot loads on new and 1x brass, measure &trim all cases. I actually like 800X and Longshot.

 

Trimming cases and 800-X. You are a glutton for punishment! Or just really enjoy time spent at the reloading bench.

:cheers:

 

Yes and yes !
I do know the limits of guns and powder combos. Temperature has some effect on 800x as does primers. OAL 1.250" to 1.260" with trimmed cases keeps it consistant.

 

Lee Quick Trim dies.

 

(QUOTE)
the extractor determines headspace

+1