[Buckskinner]

So I just went through my first 100 rounds on my new (to me) Dillon SDB. Because it was set up for SWC, and I had 500 SWCs laying around, I used these first. They were a bit messy as a bit of lube (I'm calling it lube, its green in a band around the circumference of the bullet. Gas check? ) and a tiny shaving of lead usually gets smeared on the bullet and brass, and sometimes drops onto the shell plate. Other threads I've read talk about adjusting the bell, and keeping the seating die clean. Which I will work on tonite. But now I"ve got these rounds that I'd like to clean in bulk. What's the word on tumbling loaded rounds? Sounds dumb, but there is some mention on other threads of doing just this, and for the same reason...

[Hemicuda]

From what I understand, it is likely a BAD idea... tumbling loaded ammo can "crush" or break up the grains of powder, causing it's burn characteristics, and causing a possible overpressuer situation...

this is only something I have heard (here and elsewhere) and I actually have never done this, so I am NOIT an expert, but the explanation SEEMS plausible to me, so I don't tumble loaded ammo... YMMV...

[BluesBear]

Tumbling loaded ammo enough to clean it won't hurt the powder a bit. This is another internet myth.

If bouncing cross country in the back of a semi-truck from the manufacturer to the distributor to the dealer didn't break down the powder, a little bit of tumbling won't either. In fact the major ammo makers thumble theirs too.

I have found that corn cob media is better than walnut hull media for polishing loaded ammo. A good squirt of Semichrome polish in the media will make them sparkle and resist fingerprints.

[HSMITH]

I agree with BluesBear.

[lycanthrope]

No problems with tumbling live pistol rounds.

Check your crimp. The smear usually comes during the crimp process. It's easy to crimp lead too hard.

[Buckskinner]

Finished tumbling. I say "ooooooh". Nice and clean...

I changed the bell slightly, and that helped the smear. I'm not very technical, but it seems to me on the 1911, the rimless brass needs to have a clear delineation betwixt brass and bullet. Over crimping and lead/lube build up on brass could be a problem, no?

[BluesBear]

Yes Buckskinner, since .45acp headspaces on the case mouth you need a clear "line".

You actually don't crimp autoloader ammo. A taper crimp is applied that actually just resizes the case mouth area so it holds the bullet tighter.
Revolver rounds which headspace on the rim actually have a crimp that is curved or rolled into the bullet to grip it.

[Buckskinner]

"headspaces on the case mouth"! I knew there was a proper way to express that! Thanks BluesBear.

I compared the verrrrry slight "crimp" to the factory loads, and it appears very similar. Not sure to what degree my eye is calibrated for, but its within a fraction of a cat's whisker.