Originally Posted by
thx997303
Gear,
I made a shotcup containing 300 gr of shot, unfortunately it was too long to cycle in my marlin's action, and when I managed to get it out of the mag tube, I chambered it just to see.
Of course that was dumb. The darn shotcup got stuck in the rifling and had to be driven out. That's why I suggested a .45 ACP case for a forming collar, it shouldn't be much more than .451" ID at the mouth and gets smaller very quickly toward the case head, you could section the case somewhere between the case mouth and head to get a collar the right length, taper, and ID to form a good nose on you shotcup that would ride inside the lands. That way, at least in theory, you could make a cartridge that would approach the max OAL that will feed in your gun and still be able to extract it from the chamber intact.
I think that with a bit lower powder charge, I should be able to get about 300 gr of shot in there.
I'm thinking I may just reduce the powder charge to 10 gr. Should be sufficiently cat sneeze. Only one way to find out!
With the compressed powder charge, I don't think we get into any dangerous areas like SEE, even with light loads of the slow burners. No real danger of that here, or with Unique period.
I wonder though, wouldn't having only the one seam do some pattern deformation? Why do you only have one seam? Yes, it will deform the pattern. Take a razor knife of some sort and slit the shotcup in one or two places lengthwise after forming the base so you have two or three petals like a shotgun wad, that way it will expand evenly like a flower and brake quickly upon muzzle exit allowing clean shot departure.
And how far from the muzzle would you suggest I place the cardboard? Ten feet. Wear your safety glasses!
Another thing, I was thinking about the whole lack of a shock absorber in these loads.
Got me wondering if a thin slice of hot glue attached to the base of the shotcup would be sufficiently shock absorbing. Might also give a bit more square base. I would think the wad leaving the shot as uniformly as possible would be a good thing. IDK, perhaps you can try it and see, the proof of any improvement is in the patterns and the condition of the recovered shotcup, and in a rifled, cylinder-bore barrel there is only so much you can do.
Well, I better get a hold of some more shot so I can do some testing. I think I have a bag of it somewhere.