How much insurance for power factor?

[toxic]

I'm curious about your overall length of your .40 rounds.

I don't 100% trust my cheap micrometer but according to it: 1.138
I'm using shooters choice cast bullets and the way the bullet is made I pretty much have to use that length.

 

[Dan-O-Mite]

I use Plains Ammunition hard cast lead, which are round nose, 180 grain bullets, for practice. I used to load to a length of 1.140" but found a big difference in velocities, over 50 ft/sec. at times. I load closer to 1.160" now, much more consistant.

I had read, and been told, to be careful of pressures in the .40. I thought I must have been right on the line which was causing the differences.

When I read that you are getting that power factor with that amount of powder, I figured you were probably loading shorter than I was.

 

[toxic]

I had read, and been told, to be careful of pressures in the .40. I thought I must have been right on the line which was causing the differences.

When I read that you are getting that power factor with that amount of powder, I figured you were probably loading shorter than I was.

Are you suggesting that the shorter length may be creating too much pressure in my loads? I've never seen any signs of that but I am still pretty new to this...