When do cases need to be trimmed?

[hydro556]

As a new reloader,loading for 3 months), I am trying to determine when cases need to be trimmed. I currently only load one round. 308 for my Savage 10FCP. I havent taken a ton of measurements on my fired cases, but the ones I have measured are almost identical to the unfired ones. What guidelines should I use to determine when to trim? I dont want to spend a ton on a trimeer, because I dont think I will be trimming that often. I have heard pretty good things about the Wilson trimmer. Is this a good trimmer for the money?

 

[billmo]

As good as you will find. Since you have already fired some of your brass, I would not trim until the brass was approaching the max. length listed in your reloading manual. Bill

 

[284driver]

Wilson is the best. Squares the case mouth perfectly, unlike most other trimmers. Relatively inexpensive compared to some of the other ones also.

Good luck.

 

[Winchester69]

Sinclair sells a plug that fits in the end of a case that, with a caliper, allows you to determine your chamber's maximum case length. As long as your brass is less than the length measured, you have no worries.

The Wilson trimmer is excellent, unless you're trimming hundreds of cases at a time. Then you need something electric.
.

 

[280man]

I like the forester been using one for years no problems as far as when to trim all you are looking for is every case to be the same and some where under the book max case length

 

[Rust]

Using the Sinclair chamber length measuring inserts is simple, take a fired case, neck size it, trim about half the neck length off, insert the insert, load it in your chamber,and the chamber has to be CLEAN) and measure the resulting length of the case and insert. This will be the maximum case length allowable. Some folks will trim .002" off of max or so but with that little clearance you've really got to watch the neck stretch on every case. .005" is fairly generous. How often you measure your brass to determine if it needs to be trimmed depends on what you are shooting, how hot your loads are, how tight your chamber is, what length you've previously trimmed back to, and how good your brass is.

 

[Preacher]

I just open the primer pocket on a old case and check the length with a borescope, and go from there. Never seen a case that was to long.....
Nice to have them all the same length, but they generally don't need trimmed for any other reason....