Trim

Tribe

Gunny Sergeant
Full Member
Minuteman
Apr 10, 2007
1,508
2
Wetside, WA
1. What do you use as your "rule of thumb" for when to trim?

2. How do you determine your MAX length before you MUST trim?

3. What is the end result if you fail to trim when you "MUST"?
 

Fuzzball

Gunny Sergeant
Full Member
Minuteman
Jan 19, 2009
2,165
5
Re: Trim

"1. What do you use as your "rule of thumb" for when to trim?"

Book max case length.


"2. How do you determine your MAX length before you MUST trim?"

Same book, same length.


"3. What is the end result if you fail to trim when you "MUST"?"

I get nervous. May be safe but being wrong would be disasterous.


Okay, I actually have Sinclair type chamber length plugs to find the front edge of my chambers. Most chambers are longer by some 15 to 40 thou but it's by no means consistant,. I know one guy who has a chamber only a couple thou longer than max book case length! There is NO advantage to allowing cases to grow longer than normal SAAMI max length so I don't allow it.
 

MitchAlsup

Gunny Sergeant
Full Member
Minuteman
Feb 19, 2007
1,654
3
Austin Texas
Re: Trim

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tribe</div><div class="ubbcode-body">1. What do you use as your "rule of thumb" for when to trim?

2. How do you determine your MAX length before you MUST trim?

3. What is the end result if you fail to trim when you "MUST"? </div></div>

I run the brass through the trimmer every reload cycle. Takes less then 3 seconds per round with the lathe, no reason not to.

If you do not trim and the case gets signiicantly out of spec, it can get long enough that when fired, the end of the neck runs into the end of the throat in the chamber. And having no where else to go, it will turn inwards and grip the bullet like nobodies business. This leads to massive pressure build up and "bad thngs can happen".
 

Victor N TN

Retired civilian fart
Full Member
Minuteman
Feb 16, 2002
4,025
12
68
Knoxville TN
Re: Trim

Using a slice of the case neck to make a ring on a long bullet, from a fired case and tested 10 times, my trim to length is minus .010 from the actual max length of 2.035"