Roger,
Sounds like your expander is plenty small at .427". You'll want to watch running an expander that is too small. With the straightwall cases, they tend to start bulging out one side as you are actually using the bullet to expand the case when seating.
Ball powders are much more difficult to compress as they are already in a dense state from the get go. I would back off the charge a bit like Bill recommends. Too much compression with ball powder can also lead to poor or erratic ignition with the powder almost becoming a solid mass under heavy compression.
Notice that Bill illustrated he only lost about 70 FPS with a 2 grain drop in powder. That should tell you something about the burning efficiency under heavy compression.
FWIW,
Ray
(Edited by Contender at 10<!--emo&:0--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'><!--endemo-->4 am on Dec. 18, 2001)
Sounds like your expander is plenty small at .427". You'll want to watch running an expander that is too small. With the straightwall cases, they tend to start bulging out one side as you are actually using the bullet to expand the case when seating.
Ball powders are much more difficult to compress as they are already in a dense state from the get go. I would back off the charge a bit like Bill recommends. Too much compression with ball powder can also lead to poor or erratic ignition with the powder almost becoming a solid mass under heavy compression.
Notice that Bill illustrated he only lost about 70 FPS with a 2 grain drop in powder. That should tell you something about the burning efficiency under heavy compression.
FWIW,
Ray
(Edited by Contender at 10<!--emo&:0--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'><!--endemo-->4 am on Dec. 18, 2001)
