Can a tighter crimp improver consistency?

[gwalchmai]

I been tryin Universal under some 200gr RNFPs in my .45Colt and I gettin inconsistent burning. No residue, but some loads go POP and some go BOOM. Doin the old "point in the air before firing" trick, like with Unique, help some, but I like to avoid dat. I a gonna try a lil tighter crimp and see if it help. Now I usin a light roll crimp into the groove.

I seen this with loads from 7 to 8.5gr of Universal, btw, and I didn't notice it with 265gr bullets.

[918v]

Sure. Your light crimp may not be retaining the bullets well enough and they are pulling out under recoil. Not enough to tie-up the gun, but enough to screw-up consistency.

I have a 625-7 and have a hard time retaining bullets using a taper crimp. Hornady swaged bullets always pull out. Lasercast always stays put. So I started seating slightly past and crimping over the shoulder. This works for SWC, but not for RN.

Swaged bullets are soft. If you crimp the case mouth into the shank, it will cave in. But it won't spring back any, so in effect you will lose tension. Hardcast bullets do spring back a bit, so little tension is lost.

[JLarsson]

Tighter crimp might help. Really sounds like inconsistent ignition due to to light a charge (position of powder in the case, as you suspected) or varying charge. You loading these progressively? I figure you for a "check your charge" kinda guy, though.

Shouldn't matter, but what primers you using? That's a pretty big case for not much powder.

[gwalchmai]

Yeah, I suspected the charge may be varying as I'm doing these on the 550, but every one I check is spot on. And the 265s were loaded on the 550, too, and they OK.

I'm using WLPs, and I've never had any problem with 'em. They all seat well in the 550.

918, I cheked but I haven't found any pulling.

[918v]

Then the crimp is sufficient. The issue must be chemical in nature. try a different primer, like FC150 and increase/decrease the powder charge. Also seat the bullet flush with the case mouth and rework the load using 45 ACP data. That weill reduce powder positioning issues that may be the culprit here.

[4eyes]

Try a faster powder. Not many cowboys use Univ or Uniq.