Personally I would opt for the .25-20. A lot less lead use- 2 or 3 .25 bullets for every .357 bullet. Powder charges probably roughly the same so no difference there. Brass is an issue, but I see .25-20 brass pop up from time to time and if you keep up a concerted effort to look for it you'll eventually have a stash built up. Heck, I shoot cartridges based on the .25-20 Single Shot case which has been discontinued from mainstream sources for about 70 years now. Compared to finding that stuff .25-20WCF brass is a piece of cake. Besides, you can use .32-20 brass and even .218 Bee brass in a pinch which gives you more options in your search.
When a fun paper punching/plinking gun is being considered I always opt for the smallest cartridge, for economy if for no other reason. Plus, how many foot pounds of energy are needed to put holes in paper at 50 yds.? If small game is in the offing too, then the .25 is more reasonable IMO but if there's slightest chance that I might take it for a walk in the deer woods then I would up the ante to .357 Magnum and shoot .38s in it during the Spring and Summer.
I have a small Martini action patiently waiting for its turn on the project bench, but I'm leaning toward .22 Hornet for it. Cast bullet plinking with a Hornet is cheaper than shooting .22 rimfires these days. I already have a dandy Hornet but you can't have too many Hornets IMO!
Last edited by gnoahhh; 04/09/15.
