LiveLife
Member
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..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?
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.