Mornin' Gents,
Here's a SLICK setup that I've had lots of luck with.
Actually it's in no WAY slick, ...more grabby than Al Sharpton at a Harlem fundraising event.
With the barrel vertical in a bench vise, I "Dam" around it's lower radius with index card weight cardboard and cheap masking tape. The aluminum blocks are set on top of the platform created and clamped together with several thicknesses of the same cardboard fitted in on the parting line. Naturally the inner vertical edges have been cut to mate to the barrel's profile. Doesn't have to be anything fancy, just has to work ( once).The blocks are taped to the lower cardboard dam. With a can below to catch leakage, this lash up is poured full of a cerro-alloy.The stuff I use is a commercial version of "Cerro-Safe" and WAY more affordable. I think it goes to liquidous at around 180*F,....Boiling water cuts it,...so it's real handy for "Shoring" fragile lever gun receivers, too. Dittos holding queerly shaped parts for milling ( but you BETTER keep things nice and cool ).
The stuffs almost crystaline hard, in its solidous.
Anyhow,...once poured...one can bust the thing loose almost immediately, sprinkle on the rosin, and trim off any "Flash" that'll deter a solid grab / fitup.
As noted, in NO WAY slick,....very FAST to set up, and a system that's yet to let me down. I don't own any "barrel bushings",....just a can of that cerro alloy, and those aluminum blocks. Time allows, I will make up something with pins, like a bullet or ball mold,...If really inspired, I guess one could cut out some light sheet metal lower dams.
Oh, on another note entirely, I have a bag full of parts marked Win model 100,...and will likely never need them,(they're newer than 135 years, ya' know
.) They look like the guts of an action, transfer bars and such.
....I can lay them out and take a pic, if anyone's in need of em'
cheers !
GTC