.357 Magnum Crimp and Bullet Movement

[Erik16]

['ol shooter]

That would work for me. Honestly, I just put a good crimp the revolver ammo, and have never had an issue in twenty-odd years. If I'm within a couple thou of the spec, I call it good.

[hambam105]

Plated bullets, right? How did I know?

Measure you bullet length before seating. Remember...the bullet, not the cartridge...tell us what you have.

[Erik16]

Nope, using Nosler jacketed 158 grain bullets.

[hambam105]

Good.

There is a difference between cylinders with most revolvers. Some cylinders are holding the cartridges tighter than others.

Check velocities as well. But I really wouldn't worry it me too much. I've successfully reloaded a couple thousand full pressure .357 mags and this has never been a concern for me or anyone eles I know.

[Whiterabbit]

Works for me. I assume .007 jump is far away from OAL = cylinder length?

[hambam105]

Might be half that due to measuring error...so what is a shooter to do? Shoot!

[hermosabeach]

So final die sets bullet depth and crimp.

Unscrew the seating guide, turn the die a bit more into the loader and increase the crimp.

How does the crimp appear visually?
Forcing brass into the bullet is too much...

Roll crimp or taper crimp die?

[pacrat]

0.007Is this normal for .357 Magnum to get a small amount of movement?

Comments as to perspective. Some things in reloading. A "few thousandths" make big differences. Other things a "few thousandths" make no difference. OAL on pistol cartridges is one of the latter.

Now to your numbers..... Largest movement you had was only .007". For perspective, that is a little less than twice the thickness of an average human hair. Even using a Ransom Rest, you would never be able to discern any difference in accuracy with that tiny difference in OAL. Especially from a revolver, with its many inherent variables that you have no control over. Like variances in different chamber alignments with barrel/cylinder. And cylinder gap.

If you are loading to the 16.4 gr charge, that is close to max for Win-296 and a 158 gr jacketed bullet. I would be surprised if you didn't have a small measurable amount of bullet slip after 5 rounds with a load that stout.

That's the long answer, with explanation attached.

Short answer.............You're GTG............Choot Em.

[hambam105]

What's 0.007 inch between friends?