Strange Thing with 38-40 Cowboy Dies

[rbertalotto]

I have a set of RCBS Cowboy Dies that I use to reload 38-40 cartridges.
Last night while reloading a few hundred rounds I saw that the resizing die was creating long scratches in the 38-40 cases. So I removed the die and cleaned it out. Scratches still remained and I could see faint scratches inside the die. I them used a bore mop with 600 grit wet sandpaper and polished the interior of the die to a near mirror finish.
The next ten rounds resized looked great but on the 11th round I started to see the scratches again and by the 20th round the scratches were deep enough to feet with a fingernail.

Looking into the die I could see faint scratches again! I polished it again with the 600 grit and really cleaned the snot out of the die and the de-priming pin. Reassembled and same results....First 10 or so look great and then the scratches reappear and get progressively worse.

These scratches appear all around the case about a 1/32" apart from each other.

I've been reloading for over 40 years and I've never seen anything like this before. I've had dies that would scratch a case but a bit of polishing always made things right again.

Any ideas???

[downwind]

In reading your past posts, I'm quite sure you have flushed out all remaining grit from the polishing process, from all parts including the decap portion. This was my first thought and I figured I'd pass it on.

I had an old used set of RCBS dies for 44 WCF that did the same, polished it out, some scratching still remains, but in shooting black powder it doesn't seem to matter much.

Maybe I'll revisit the issue.

THANKS
DOWNWIND

PS Are you starting with CLEAN cases?

If so, maybe some grit being transfered while loading?

[LUBEDUDE]

I'm with Downwind

It sounds like you did a great job polishing. And a lot of junk really got impacted up top insided the die. Heat could have solidified it somewhat and it glued itself to the topside of the wall and just would not quite flush out. So when you run a case up the die, it acts as a scraper in a micro fashion and drags the crud little by little on the walls of the die causing the scratching.

You may have to use a hard plastic pic to get up in there and flush obsessively with brake cleaner. Use tooth picks and make long picks out of wood dowels.

May even just soak the die in Kroil,carb cleaner, mineral spirits,etc., for a night or two.

Good Luck

[rbertalotto]

A few notes and a fix...

I use "One Shot" spray on lube. My brass is vibrator cleaned in corn cob media.

I went back into the reloading room and cleaned them out again. With my naked eye I couldn't see any scratches, but with a magnifying glass, they were there. You could feel them with the blade of an Xacto knife.
I found a tight fitting bore mop and saturated it with 500 grit valve grinding compound and in an electric drill I honed the bore. Runing the drill forward and back and up and down like you would honing the cylinder of an internal combustion engine.
The interior now looked like a mirror and I resized 100 cases without an issue.

I'm still not sure what scratched that die like that, but it seems to be fixed.

Might be time to go back to my all time favorite dies...LEE.....Can't scratch those puppies!

[LUBEDUDE]

Glad you fixed it.

I have Cowboy dies in 38-40, 44-40, 45 Colt, 45-70, and 357. I have not run into any problems yet. You now have me wary.

[.22-10-45]

I have had this problem with my .40-70 straight sizer dies..and I am only partial neck sizing. Polished out to mirror finish & this time, I took a tumble cleaned case & polished neck area with fine steel wool & cleaned with degreaser..then re-lubed with clean fingers..scratches again!..I knew it couldn't be grit on case. With magnifier headset & looking thru die at light sorce, I could see what looked like scratches..but then on closer examination...something was sticking above surface. Polished right out..I now believe what has been thought were scratches in die is really brass particles..being galled off case.