Problems loading Mangus HBWC in 38spc..

OK, so Ive been loading for about 5 or so years...  Ive loaded thousands of cast wadcutters in 38spc during that time, and no real issues to speak of..  I picked up a box of these HBWC to try, and I'm having a heck of a time. I have the case expanded using a Lyman M die, and they start about a 1/4 of the way in the case..  Ive tried my two different seating dies... one for my normal button noise WC, and one for RD, and they bolth seat the bulled about 3/4 the way, then it seems to kick over, and shave one side of the bullet.. I have the dies set so they don't seat/crimp together so its not crimping too soon..  Any one have these issues with these? Something I'm missing in my prosses that didn't come up with the cast WC I normaly load? Its really got me baffled.

I've loaded only swaged .38 SPL, 148 gr. HBWC over the years. I have never used the Lyman M die. I use standard Lyman dies with carbide sizer. I bell the cases with the standard die. I taper crimp with a separate die. I've never had your issue. My first guess would be that it has something to do with the Lyman M die.

With my Lee press, I had to increase the flare to the max I could before it started giving issues in the crimping die that comes after. I also ground the seating stem so that it had a flat nose. That solved the shaving problem for me.

My seating stem is already flat. I use the oddball Lyman truline jr, and the matching 310 dies to seat and crimp...  its strange but has worked for me well till now...  I thought the cases were belled enough, but Ill try belling a little more, and see what happands.

If I remember the M die is a long taper.
I've had excellent results with the standard Lee through powder expander dies.
You need just enough belling to allow starting the bullet.1/4 is too much.

james r chapman wrote:If I remember the M die is a long taper.
I've had excellent results with the standard Lee through powder expander dies.
You need just enough belling to allow starting the bullet.1/4 is too much.

That's what I always thought.. that's why I didn't bell more..  Ill have to go through and see exactly where the problem is accruing, and   fill in the details of my findings...

I use a LOT of case mouth flare and make sure the bullet is square (coaxial to case), but I am sure you also do that, and use a Lee seating stem with a hollow in the center so the button nose isn't flattened.
You can also try a Hornady New Dimension Seating die as it has a "tube" the bullet goes into to keep the bullet aligned during seating.
I have several M-dies and i have never solved a problem with one. 
More accuracy is lost due to insufficient flare than cases that are saved by too little flare.