Brass length

[Kenny]

I am loading rifle ,mostly .223 and 308 some 22-250 just wondering how fussy should I be about trimming brass. Is .010" over size too much. My guns a all heavy barrels , so I am trying for one hole groups.

 

[Dmay]

You can measure the exact length of your chamber, then you know you're not trimming unneccessarily. Sinclairs sells neat little buttons to do this, or do a chamber cast.

 

[maynard]

Depends on how big a hole you're talking. Are you looking for benchrest numbers in the 1's and 2's or are you looking for 1 MOA or 1/2 MOA.
Trimming your brass to a consistant length is a start. However just because your brass is trimmed and sorted by weight or by volume doesn't mean a 2 MOA rifle will start shooting 1/2 MOA.

 

['Boo]

Is .010" over size too much.

Get a reloading manual and read it.

Depending on the chamber of your rifle 10 thou over on case length could well be enough to crimp the case mouth heavily into the bullet and cause pressures to raise to the point you destroy your rifle and likely parts of your anatomy.

 

[604shooter]

Invest in Lee case length guages and cutter. Using them is a no brainer.

 

[Boomer]

The simplest solution is to set up your trimmer for the cartridge in question, then after resizing, run the case through the trimmer, if it trims all is good, and if it doesn't all is still good. Power trimmers have a real time saving advantage in this respect.

 

[beretta boy]

I trim to the recommended ( usually .010" under SAAMI max) then again when the case stretches to within .004" or .005" of max. I've found some hotter loads will stretch a case .005" / firing.