Note, I’m not an engineer, so my use of calipers is… my best efforts. All of these dies have been used by me before and made excellent reliable ammo.
I’ve taken measurements of my lee powder through expander dies for the below calibers. The hollow expander insert is where i spent most of my efforts measuring. It is a hollow shaft that has an abrupt step to it where the cone expander begins and then tapers narrower. I measured 1: the tip to tip length of the hollow expander plug 2: the length of the expander cone 3: the inner diameter of the narrowest side of the expander cone (a useless measurement now that I think of it) 4: the widest point of the expander cone 5: the narrowest measurable part of the expander cone 6: the die’s mouth at the bottom where the case enters.
32 auto
1: 1.543
2: .184
3: .327
4: .319
5: -
6: .362
380 auto
1: 1.452
2: .190
3: .254
4: .362
5: -
6: .348
38spl/357
1: 1.100
2: .314
3: .280
4: .377
5: .356
6: .372
40 sw/10mm
1: 1.302
2: .202
3: .310
4: .410
5: -
6: .452
45 colt
1: .970
2: .290
3: 312
4: .462
5: .449
6: .503
There is a bevel below my #5:, but I’d imagine it would crush the cases more often then successfully expand with that bevel. There is also a bevel above my #4:, but again I think that would also potentially crush cases as it is just below the abrupt step.
I think all of the expander plugs had the same outside diameter otherwise the lee powder riser would not be universal.
Lyman #49 says the inner diameter of a 44 mag case at the mouth is .432”, I don’t see it getting close enough to any of my existing dies.
I wonder if the above linked post #2 44 mag expander plug would work in my 45 colt die? I’ll find out when I finally order the dies, I’ll pop the 44 mag expander plug out and try it in my 45 colt die. The small difference would only be the die mouth opening, if it's different.
At this point the risk/reward for buying a $3 plug with shipping, along with a $5 shell holder has me at the same impasse- just spend the extra few bucks and get the whole set.