When to trim?

[bryan35]

I have some once fired 243 factory brass that I just sized. They are all a few thousand over or under the max trim length of 2.045. Is it necessary to trim them for a few thousand over?

 

[emerson]

I find in my rifles over length brass often doesn't chamber freely. I trim back to the within spec.

 

[bigedp51]

I'm retired with nothing to do and all day to do it, so I trim my cases to minimum length after each firing. Is it necessary, "NO" but it satisfies my brass OCD.

 

[freedomintheskies]

If it is over the SAMMI spec then the simple answer is yes. I tend to prep mine like bigedp51. Trimmed every time. I also anneal every time (because I have an annealer so why not).
One reason to trim to the same length is so you can get the same amount of crimp on each round. Its amazing how much more accurate your ammo will be.

 

[sure as shootin]

If you are going through load development the more consistent the brass the better. Most people will always trim 1X fired brass to start off with so all the brass is consistent. I've been trimming after every firing but I do hear quite a few reloaders, when checking their fired brass for length, if they have at least a couple that are close to the maximum suggested, they'll trim them all.

For example,,,the suggested trim length for a .308 is 2.005. The max. length before trimming NEEDS to be done is 2.015 so if all the brass is between that range you're good to go with little, if any change in accuracy. But as I said above, if the measurement was even within a couple of thous. of 2.015 it would be best to do it all.