Case Trimming Tips?

[Dave R]

I am relatively new to reloading. Have a new case trimmer on the way. I measured a bunch of cases with my cool new micrometer. Many were a good bit under the trim-to length in the manuals.

The way I understand it, there are accuracy benefits to be had from having uniform case length. So should I trim all cases to the length of the short one, so they're all the same? Or should I just trim the long ones and let the short ones grow a bit?

Any other tips for a newbie trimmer would be welcome.

 

[swifter]

"cool new micrometer"?

Did ya mean "caliper"? Or do you have a mic that large?

Anyway, even with the short cases, trim enough to square the case mouth, then trim the rest to that length. I think its more important that they be square, and the same length, than that they be a certain length...
If that makes any sense...

Tom

 

[martin]

Dave,
What caliber are these cases you measured?

 

[Dave R]

Ummm, yeah, my cool new caliper. I'm still learning the lingo

The cases were 3 different calibers:

-.308
-.223
-.17/357 (a wildcat which may also be called .17 Saunders. Its .357 mag pistol brass necked down to .17)

In each case, the shortest cases were around .010 shorter than the "trim-to" length in the manuals.

Except the .17. I inherited that, so have no specs. So I'm planning to trim those to the short case, and just keep that as the spec, until I get ambitious enough to do a chamber cast.

 

[Nero Steptoe]

Unless you're planning on competing in benchrest, I don't believe you'll find minor case length differences will yield consequential accuracy problems. With certain types of crimping, case length is critical; however, you'll find, I'm sure, that not crimping rifle ammo produces better accuracy than crimping. Unless the cases are longer than spec., I wouldn't trim; I certainly wouldn't trim a lot of in-spec cases to a shorter-than-spec length.

If you'll spend more time experimenting with various bullet seating depths, relative to "touching the lands" (I use the Stoney Point tool), and further experiment with various powders, bullet designs and loads, you'll see dramatic differences in accuracy.