Seating Die Problems

[Marine Sgt 2111]

I bought a Lyman .38-55 and a .45 cal (short) neck sizing die. I have no complaints about eithers performance. However, when seating bullets in .45-70, using RCBS dies (from 1977) I noticed that the seating die sizes the lower part of the case that I wanted left alone. I used Lee dies to seat bullets in .38-55 and no problems but the RCBS are being a PITA. Any of you gents had this problem with RCBS dies?

[Calamity Jake]

Don't have that problem with anything I load but there are three easy fixes, hone out the ID of the offending seater, chop it off(shorten it) or replace it.

If you don't need to crimp then there's a fourth fix, raise the die in the press and lower the
seater stem.

[noylj]

Raise the die body and lower the seating stem.
Are your .45-70 cases bulged from an over-size chamber?

[Marine Sgt 2111]

I have 4 .45-70's two number 3's and two shilo's. Will try another set of dies I have from 1972 and see if it makes any difference.

[abcollector]

Sgt2111,

I almost think that what's happening is that you are sizing the case as normal in the sizing die and flaring if needed, then when you seat the bullet with the seating die, the diameter of the bullet really increases the section the brass where the bullet sits and then the portion below the bullet looks like it was sized down. At least that's how I read your question. If this is the case, you can play around with the sizing die depth (as in backing it out) as long as the resized cartridge still chambers easily.

What diameter bullets are you seating? Maybe you need a larger expander plug?

If I'm all wet, just disregard.