Trimming Auto Pistol Cases is Unnecessary & Waste of Time So That’s What I’m Doing

[Atavar]

I too like to trim my .45acp and 9mm brass for a more uniform flare and crimp.
I do sort my brass and trim to the upper middle of SAAMI range and toss any short brass in the recycle bucket.
It just makes things go smoother. Aside from perhaps wasting a little of my time it hasn’t caused any problems.

 

[Skeptic13]

I never trim pistol cases and have never had a problem. However I think if you want to trim and see it giving you an advantage then I say trim away. I just hate trimming and will avoid it at all costs.

 

[CQB45ACP]

Thanks for the comments so far. Sorry for poking a hornet’s nest.

 

[GBExpat]

Trimming Auto Pistol Cases is Unnecessary & Waste of Time So That’s What I’m Doing​

Best @SUBJ that I have seen in a while. Makes me smile. Thanks!

 

[higgite]

Oh no, CQB! No! Not the dreaded Corona 9/45 pistol brass trimming virus! Say it ain’t so! Oh, the humanity! I just hope your life isn’t ruined beyond the possibility of rehabilitation.

 

[Walkalong]

I know one person who trims.45 ACP cases, to each their own.

 

[LiveLife]

I know one person who trims.45 ACP cases, to each their own.

Yes, I do understand the reasons for trimming straight walled semi-auto pistol cases and posted this

While resized case length being same will produce more consistent flare and taper crimp amount

And suggest this

if you are looking for more consistency, instead of trimming case length, sorting by resized but untrimmed length that is longest may produce more consistent chamber pressures.

 

[lordpaxman]

Thanks for the comments so far. Sorry for poking a hornet’s nest.

It’s your time and money, spend it however you want. I‘m more interested in the ”why?”.

 

[CQB45ACP]

Well I wasn’t so anxious to length trim as I was to use the Lee tool to chamfer inside/outside.

Then I thought why not trim also and get cases into general length groups vs the helter skelter spectrum of lengths I have today.

I’ve never experienced a length issue vis a vis causing inconsistent expanding/flaring since I use nearly zero flare. So that’s not persuasive to me at all.

But, since it’s all a one and done exercise, what’s the biggie I thought.

I hereby confess to having found a few too lengthy 9mm cases in the past and used a fine wide file to shorten them. It worked and I still use those cases today I presume (can’t be certain since I don’t track losses/recoveries that closely).

Edit: @lordpaxman i was typing this before reading yours. I’m a low volume shooter (couple hundred 9mm/45acp per week is a lot) and get up close and personal to each case—deburring, chamfering, uniforming flash holes, gauging primer pockets, etc before they’re permitted into my rotation. So this was not a time add to me.

 

[jmorris]

The most elementary question I’m almost embarrassed to ask—how do you determine an appropriate case length?

You can generally find that information right before the load data.

 

[cfullgraf]

If the round gets a taper crimp, primarily ammunition designed for semi-auto guns, do not get trimmed.

If the round gets a roll crimp, primarily high power rounds such as 357 Magnum, 44 Magnum, etc., get trimmed. But, it is usually a one time thing. Trimming is requirred for a uniform roll crimp but the cases do not change length much over the life of the case.

One exception is 30 Carbine. When fired in a 30 Carbine, the cases do grow over several firings and since the case headspaces on the case mouth, trimming is necessary. Not a hand gun round per se but it is a straight walled round.

Another exception, I form 38/45 Clerke cases from 45 ACP cases. Trimming is part of the forming process but they never get trimmed after that.

 

[mdi]

he most elementary question I’m almost embarrassed to ask—how do you determine an appropriate case length?

If I trimmed handgun cases I would use the "trim to" dimension in my manual(s).

 

[deadeye dick]

Since you are new to THR and we have already discussed not trimming straight walled semi-auto pistol cases countless times, here's one more time why.

When chambered round is fired, case rim is pushed back against the breech wall face and expanding gas will push the case mouth out towards the chamber wall.

If case mouth is not in contact with forward part of chamber, more gas will leak around the case mouth until case mouth expands to seal with the chamber wall (Why we see Titegroup burn/soot on cases and dirty spent cases from blowback action PCCs). Trimming the case to make it shorter will push case mouth further away from chamber and likely leak more gas until case mouth expands to seal with the chamber wall. (I want my case mouth closer to forward part of chamber for less gas leakage)

While resized case length being same will produce more consistent flare and taper crimp amount and likely will push the bullet out the barrel, if you are looking for more consistency (Especially for match shooting), instead of trimming case length (Are you resizing before or after trimming?), sorting by resized but untrimmed length that is longest may produce more consistent chamber pressures.

Of course, just my humble opinion.

Exactly my thoughts

 

[berettaprofessor]

I don't trim auto cases (any of them) but if I did, I wouldn't use the Lee Deluxe Case trimmer. There are much faster and this more cost effective ways to trim brass, especially a lot of it.

 

[GeoDudeFlorida]

Well I wasn’t so anxious to length trim as I was to use the Lee tool to chamfer inside/outside.

Then I thought why not trim also and get cases into general length groups vs the helter skelter spectrum of lengths I have today.

I’ve never experienced a length issue vis a vis causing inconsistent expanding/flaring since I use nearly zero flare. So that’s not persuasive to me at all.

But, since it’s all a one and done exercise, what’s the biggie I thought.

I hereby confess to having found a few too lengthy 9mm cases in the past and used a fine wide file to shorten them. It worked and I still use those cases today I presume (can’t be certain since I don’t track losses/recoveries that closely).

Edit: @lordpaxman i was typing this before reading yours. I’m a low volume shooter (couple hundred 9mm/45acp per week is a lot) and get up close and personal to each case—deburring, chamfering, uniforming flash holes, gauging primer pockets, etc before they’re permitted into my rotation. So this was not a time add to me.

That’s why I only load fifty at a time. Halfway through I start to forget their names. I don’t want to offend anyone.

 

[Slamfire]

Trim to your heart's content. It won't hurt anything, and in time, you will get tired of doing it, because it does not help anything either.

I never shot bottle neck pistol cases like the 38/40 or 44/40. Maybe they need to be trimmed just like bottle neck rifle brass.

 

[PistoleroWadcutterGANG]

Those that trim are stalwart in nature and diligently stand the line. Those that don't trim are out having fun and having beer and shooting fun. I trim because happiness is offensive, lol

 

[Bcwitt]

If you sort cases by length, as I have, you can find a length that is more accurate. For a perfect chamber fit, get some 45 win mag brass & custom cut them to your chamber to minimize headspace.

 

[CQB45ACP]

If you sort cases by length, as I have, you can find a length that is more accurate. For a perfect chamber fit, get some 45 win mag brass & custom cut them to your chamber to minimize headspace.

Oh yeah a new hobby

 

[Bcwitt]

I do not recall which edition, but DAG discussed this in ABCs.

 

[Blue68f100]

I sorted a large batch (2k) of 45acp once, never again. What I found was longer the case, the more consistent the SD, SE, fps were. Reason being the longer the case the better they seal. As for which mfg was the best. PPU had the most consistent OAL of all, normally it was within 0.002"-0.003" of max chamber length. All the others were all over the place, from as much as 0.010" below to an avg of a few 1/1000 above min. I could not tell any difference on target with me pulling the trigger. Maybe a high master could but not me. These were all fired in my custom 1911 BE gun.

 

[CQB45ACP]

I do not recall which edition, but DAG discussed this in ABCs.

I just looked through 6th edition. Didn’t find it but not really sure what I was looking for either

Just looked at Starline—expensive stuff .32/case & large primer. Set up for heartache. Thanks

 

[FROGO207]

You were asking the trim length. With the Lee trimmer and stud the length is already set in stone you cant go longer and would have to grind some on the length pin to shorten it.

Now on to trimming itself.

 

[CQB45ACP]

You were asking the trim length. With the Lee trimmer and stud the length is already set in stone you cant go longer and would have to grind some on the length pin to shorten it.

Now on to trimming itself.

You mean max is set but not less than max, right?

 

[theotherwaldo]

You mean max is set but not less than max, right?

Yep.
I gauge and inspect all of my brass, though.
Only the stuff that is over-length even sees the trimmer.
Only the stuff that is unchamfered sees a chamfer tool.
This actually speeds up the process of reloading for me.