The .357 was more of a fact-finding science project to determine comfort with handgun while seeking top end with the carbine, so for a sense of what these things might be capable of for accuracy, we probably have a better idea with the .44:
Dad's got a comfy Special-level Titegroup load with his .44 Mountain Gun, so we just zeroed up for that and let fly at 50 yards.
The .357 got a lengthy workup. This is a 50 yard cluster with an increase of 0.2 grains additional 2400 every six shots:
The goal with that was to shoot an equivalent load through my "Free" 66-1 to see if I could come up with a comfortable handgun load that got enough of a velocity boost through the carbine to be acceptably flat-shooting over 100 yards. Trying to get a point-blank / up-down of 6" or less.
The red dots have a (theoretically) 2 MOA dot that I sense is probably closer to 3 or 4, so as usual with such things, I have to put a big sample of rounds up and guesstimate accuracy potential by the majority. I suppose I could temporarily hang a 6.5-20 to wring them out, but that isn't what these guns are for. From today, I get a sense that they are probably honest 2-minute guns with the human factor and the CQB sighting systems removed.
The 66-1 was comfortable to the 1000 fps I loaded it up to - which got up to about 1200 fps out of the 16" barrel. I had something of a brain fart with the carbine - the bullets used were cast out of our low speed pistol mix of rendered jacketed bullet cores with an added 3% tin. At 10BHN hardness they work great for .45 ACP, .44 Special, 9mm, light .38's etc. . ., but the wheels started coming off the groupings somewhere around 1300 fps. 1200 fps SHOULD serve my mission goal for trajectory, but the "little voice" kinda wants to find the top end for the carbine. I'm probably cast some more out of a 12 to 15 BHN alloy and repeat. I may say "screw it, I'm done" TBD.
REALLY happy with my custom 170 grain mold!