M die & Starline brass

[lurch]

I just got an M die for 380ACP. I tried it out and while it does the first stage expanding just fine, the secondary step is just not working. When the brass hits that secondary step, it bulges the case about half way down rather than put the step in at the case mouth. I don't know if the brass is just soft or if the die is bum-fuzzled. The brass is new Starlline.

Has anybody else seen a similar issue?

[Black_Talon]

Chamfer/deburr the inside of the case mouth first. New brass always needs it, outside and inside. Factory-new brass usually has a fairly decent burr left by the cleaning/tumbling process.

[oneokie]

Take the plug out of the die body and use your finger nail to feel for a sharp edge/step at the transition of size.

[lurch]

Chamfer/deburr the inside of the case mouth first. New brass always needs it, outside and inside. Factory-new brass usually has a fairly decent burr left by the cleaning/tumbling process.

I know that you don't know me, but give me a little credit...I have loaded a round or two before. :kidding: And no disrespect intended.

[lurch]

Take the plug out of the die body and use your finger nail to feel for a sharp edge/step at the transition of size.

I gave it a once over while this was going on and didn't notice anything. Just checked again with TP and still don't find anything. I'll take into work tomorrow and have a look with a stereoscope.

[ReloaderFred]

New brass has been cleaned after the forming process and there's no lubrication from soot, carbon, etc. on the inside of the case. This causes the M die to grab the brass, rather than slide along it. I pulled some new Starline completely in half with a Lyman M die and had to cut the top half off the mandrel.

Try some dry lube, or even case lube, and see if that helps. You can tumble it afterwards and remove the lube. I won't try to load any new Starline brass until I've tumbled it for a couple of hours first. This seems to provide enough lubrication that it will expand properly.

Hope this helps.

Fred

[lurch]

Thanks Fred - I'll give that a try tomorrow. A little while ago, I did try the die on a couple 9x19 cases just to see what would happen and I got good results. The boolit slides in just fine that first .040" or so just like it's supposed to. That I think rules out the die itself being the issue. This is the first time I have used brand new brass with an M die. All other times it's always been at least 1x fired.

[lurch]

Well, a little lube certainly did the trick. Tumbling a pot full of brass now to see if that will impart sufficient lube to do it as well.

Thanks Fred.

[ReloaderFred]

You'e welcome, lurch. It drove me crazy the first time I used new Starline .38 Special brass and a Lyman M Die. It kept getting harder and harder to pull the brass from the flaring die, and finally pulled a case in half. When I looked at the previous cases, they were visably stretched to the point they had to be scrapped out after pulling the bullets. This was on my progressive press, so I thought something else was causing the problem, but it was the new brass and M die combination. I've never had that problem with any other brand of new brass, so it's something to do with the manufacturing process Starline uses.

I tried polishing the M die mandrel with Flitz to the point of actually being able to see my reflection in it. The very first case I tried after polishing seized on the mandrel and stretched. When I looked at the freshly polished mandrel, it had traces of brass stuck to it again. I changed over to an RCBS belling die for the rest of that batch of brass and that worked. Some people rave over Starline brass, but I don't find it any better than any of the other major brands, though it's becoming cheaper than the others in some calibers.

Glad it worked out for you.

Fred