Initial Case Prep and Trimming

[TrapperReady]

I am brand new to reloading rifle cartridges, so please excuse what is probably a dumb question.

When prepping brass for the first time (ie. new/unfired brass), how much below the maximum cartridge length is it OK to go? For example, I'm prepping .223 brass for Highpower use. I've got my case trimmer set up to remove the absolute minimum amount of brass and still get a clean/chamfered mouth. By spec, the max case length is 1.760", but when I trim them, they come out at 1.752".

The reloading manuals seem to cover what happens when the brass goes over the max length, but doesn't mention what is an unacceptably short limit.

 

[swifter]

The "ROT" i've always used is 10 thou shorter than max is the "trim to" length. I'm of the opinion that its a lot more important to have all case mouths trimmed even than to worry over a couple thou in length.

Tom

 

[stans]

The accepted standard for trimming is 0.010" shorter than SAMMI maximum length. You might be wise to measure the cases before trimming, some might already be shorter than 0.010" below maximum and you really want all of the cases to be the same length.