Trimming pistol cases

[LiveLife]

.45acp or 9mm the flare on the case mouth may be so narrow as to barely be able to stand a bullet on it or so wide that it has a hard time starting in the taper crimp die.

I think I’ll try trimming this batch to the shortest case at .85 and see if the flare is more uniform.
The case trim length is .893. Do you think I’ll be creating any problems?

Do not trim straight wall semi-auto cases that headspace off case mouth. Resized case length will get shorter as they are repeatedly shot and resized. If you trim cases short, finished rounds won't headspace off case mouth and will start headspacing off extractor.

What I do is measure a sample of my resized brass and use shorter cases to set the flare and taper crimp so longer cases will get slightly more flare and taper crimp. As to taper crimp amount, I add .022" to the bullet diameter (Since case wall thickness at case mouth averages .011") which essentially returns flare back flat on the bullet and longer cases will add skosh more.

 

[Atavar]

The problem is that when I do as you suggest the flare on the longer cases catches and will not enter the taper crimp die.

 

[Walkalong]

Almost certainly too much flare if that is happening

 

[Highland Lofts]

He said on the shorter cases was bare minimum flare and the longer cases was to much flare.
I never ran into that problem with my range brass.

Maybe it is the brand of dies he has.

 

[Lafitte]

The only pistol brass that I have trimmed is some .44 Mag cases used for shooting 100 yard targets.
Lafitte

 

[LiveLife]

The problem is that when I do as you suggest the flare on the longer cases catches and will not enter the taper crimp die.

If there is that much difference in resized case length, then it's likely time to toss the shorter cases as they are probably dangling off extractor by case rim instead of headspacing off case mouth. (Brass gets shorter as they are fired and resized repeatedly and why I don't trim straight wall semi-auto brass that headspace off case mouth)

I reload a growing batch of 9mm brass that's around several thousand and difference between case lengths is such that using shorter cases to set the flare amount will still allow longer cases to enter the bullet seating/taper crimp die opening.

And I use minimal amount of flare that "just" allows the base of bullet to be set inside the flare, no more, using shorter cases. So longer cases receive slightly larger amount of flare but not enough to keep them from entering bullet seating/taper crimp die.

 

[gonoles_1980]

I was trimming my 38spl and 357 brass. I was doing it so I could just do three die load (crimping and seating with the same die), but it's easier just to use four dies with the the crimp die being the 4th.

 

[LiveLife]

I was trimming my 38spl and 357 brass

OP is loading straight wall semi-auto cases that headspace off case mouth, not revolver cases that need roll crimp into crimp groove which benefit from same case length.

.45acp or 9mm

 

[gonoles_1980]

Same thing with my 9mm cases, I tried trimming a few, but gave up quickly. I sort the 9mm by head stamp and use all four dies.

 

[DMW1116]

I trim 357 cases and tried to trim 9mm once but they were shorter than trim length so I stopped. I have 2 that are longer than max but I haven’t worried yet as I have several more.

 

[film495]

I have trimmed pistol brass for similar reasons to the OP, but I've found it faster to sort brass by short, medium, long ... all in spec for min/max. Depending on the size of the batch, it only takes a minute to reset a die for a few thousand difference.