Is constant case trimming necessary? This is what I found.

[ShaunW]

I FL size, then use a mandrel, then I go to the Henderson trimmer.

I found that the case length changes when the mandrel is used and it better represents what I’ll be chambering so that’s why I expand prior to trimming.
My thoughts were if I FL sized, trimmed, and then used my mandrel then I’d be assuming each case neck would lengthen the same which IMO has a low probability.

Also trimming used to be my least favorite step until I went to a Henderson trimmer. They are damn expensive but I’m glad I own one.
Another reason to mandrel before trimming is the mouth then won't have to much resistance on the pilot.

 

[Torsten Hindrichs]

If you don’t want to buy the Sinclair plugs or they’re not available, you can just sacrifice a case for the measurement.

 

[209jones]

I haven't ever got too terribly excited over case length, usually set the trimmer for .005 under max and let them grow to that, assuming brass ever grew that far, occasionally acquired some new brass that was well under min over the years, that still hasn't, maybe never will, made it far enough to trim at .005. If it's all the same length, good enough. Used a Forster for 40+ yrs now, does what I need it to do. Splurged on a 3 way cutter head for it for 1 cal to start with, ended up with 3 ways for all cal's that I own, and an FA prep ctr to do primer pockets on. Seeing as I own two guns ea in the cal's I own, it made sense to do that. Makes life with those parts of case prep pretty easy, currently using a dremel screwdriver to run the trimmer. I can understand the caution on carbon rings in relation to the neck/chamber length, especially for folk that put lots of rounds downrange in some comps and practice in fairly short order in a month, good cleaning regimen shud take care of it anyway.

 

[PhilC]

Several years ago, I purchased a Sinclair chamber length gauge which is inexpensive and easy to use.

I measured the actual chamber length of all my rifles. Even applying Sinclair safety factory, I cut my trimming down to well over 50%. For some rifle, I have never had to trim. The gauge takes the guess work out of max case length.

Forget how long ago it was I obtained their chamber length plugs and reset the "trim to" length for every bolt action rifle I own.

 

[K22]

Forget how long ago it was I obtained their chamber length plugs and reset the "trim to" length for every bolt action rifle I own.

I did the same and cut my trimming down significantly.

 

[Firearmsunlimited]

If you are shooting a caliber with a low shoulder angle like a 220 Swift you had better be checking length at every reloading session.