As I said earlier, this is mostly experimentation. I am not unaware of the limitation of a flat faced cylinder moving in air. I imagine the WC would be very sensitive to the turbulence from a supersonic to subsonic transition making muzzle velocities above 1120 fps a bad idea. I don't recall nor can I find the critical mach number for a flat faced cylinder but keeping them at 1000 fps or below is probably a good way to stay out of that region. Given the low BC of the bullet, there would be a very rapid loss of velocity from a supersonic MV which would aggravate the effects of precession.
Any of the above -- alone or in combination -- could account for the tumbling venomballistics observed. Than you for that information.
Re 2400 powder: I tried a load of 11.0 gr in a 357 case under a Berry's DEWC seated to 1.36" OAL. It was a surprisingly good load in 3" and 4" revolvers. I do have a chronograph and, next time I can set it up, I think I'll check that load for velocity.
There is a bit of method to my madness here. My wife has arthritic wrist and is recoil sensitive. I am considering having her try the 38 spl Buffalo Bore wadcutters for her 686 (3" bbl). If that works for her then I'll need a practice round. Since I don't have access to Sundles's loading data, I figure a 357 case would be my best bet for a ballistically equivalent round. I chronoed the BB wadcutter at about 920 fps from my 3" 686.
I know there are better bullets for the 38/357 -- the Speer Gold Dot 135gr +P comes to mind -- but I work with what I have. I can buy another gun and different kinds of ammunition much more easily than I can replace a wife.
Besides, I am an inveterate tinkerer.
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