Crimping in all its glory and ugliness

[markm]

Yeah... I was thinking the crimp my be bad... but I wasn't going to take my FCD die out of my progressive to run matchkings... so they get the same crimp as every other bulk load...

Turns out to be really accurate ammo.

[iracecars4fun]

so whats the most effective way of determining if a crimp is needed? check the COAL of a few random rounds in a magazine after a few shots?

[markm]

so whats the most effective way of determining if a crimp is needed?

The most appropriate way is to use dial calipers to measre the OD of the empty case's neck. Then seat the bullet and measure again.

I'd say that the diff should be at least .002" for a gas gun... maybe .003"-.004"....

Too much more than that and you start deforming shit and getting bullet runout.

If you only have .001" in neck tension, the bullets might start moving back into the caseneck.

[tb-av]

The most appropriate way is to use dial calipers to measre the OD of the empty case's neck. Then seat the bullet and measure again.

I'd say that the diff should be at least .002" for a gas gun... maybe .003"-.004"....

Too much more than that and you start deforming shit and getting bullet runout.

If you only have .001" in neck tension, the bullets might start moving back into the caseneck.

Thanks for this... I knew there was something I didn't understand about crimping but couldn't figure what to ask.

[markm]

Run several cases to make sure you don't make adjustments off of one sample.