Correct size expander for 44 Mag/SPL .431

[tacotime]

Some time ago I loaded some .431 boolits in 44 Mag in WIN and RP cases and the noticed the cases bulged by the boolit. Probably Lee dies. Later got an M die and the bulge is mostly not seen, however, it looks like the M die's second step of the expander, the one that goes deeper into the case, measures only .427. That seems small for the .431 hard cast boolit. I did not measure the Lee expander.

Is .427 really too small for the .431 boolit? What size is ideal?

Seems like I read once that the expander should be maybe .001 smaller than the boolit.

[Char-Gar]

Current production dies have expanders for jacketed bullets, which for the 44 Magnum is .429. So, a .427 expanders is correct.

When we move to cast bullets, things get a little more complex. With the rock hard commercial case or water dropped bullets, the factory expanders are fine as the bullets is not likely to be deformed.

With softer cast bullets, like I prefer, a larger expander is what I use. There are probably some custom or semi-custom expanders available which are larger, but I used a .429 expander from a Lyman 310 die set. This works fine for my .431 and .432 bhn 9 -10 bullets, however if I had one larger I would use it.

[r1kk1]

CH4D and Buckshot on this forum can make M plugs in any dimension you want.

take care

r1kk1

[tacotime]

So then, lets say I pick up some of those swaged .431 sort-of boolits. What size expander is the best here, balancing neck tension with not compressing the soft slug?

Does a .431 expander cause the case to spring back down to .430 or so when removed?

How much neck tension is correct... .001? .002? .003? And does that answer change for magnum handgun?