This is going to be the very first round ever fired through this M48 since they packed it away in cosmoline in the 50's in Yugoslavia...it's going to be a 'cast' round shooter and a 'cruise missile' launcher on top of that.
This is an old Ideal single cavity mould from the 30's and it casts about 244 grains in COWW + 1% Sn but by the time I CG and PC it, it weighs 252 grains. There are no load tables to work from....I've been asking about this in another thread looking for a load but nobody else has anything to suggest other than fast powder loads. Didn't want that.
I would like to get this round up to about 21 or 2,200 FPS.
With grateful appreciation to Larry Gibson for his input...He came up with a suggested starting point and a slow rifle powder to use for the speed I'd like to have...he said 40 grains of H4831SC or Reloader 19 or 22. The H4831SC is not sensitive to temperature swings so I chose that to start, had to go find it in town...found it first try!
This case will hold 52 grains to the base of the seated cast...this load of 40 grains is only 79% case fill so I added .5 grains of fluffed up dacron to the top of the load.
My bore is .3235" and these cast are sized .3252".
This COAL is 3.190" of a maximum length of 3.250"...I'm crimping on the crimp groove and just squeaking in under max. length.
See how this round compares to some factory Remington 170 grain RN SP's...it's a monster! The PC is a clear/copper, it's a thin coat and the copper color doesn't show up very well.
This length round fits the magazine all the way to the bottom and cycles out and into battery from either side of the stack. Thats a 170 grain RN SP under the cast round.
Heres where you fellas can start calling me 'Chicken Charlie'...I had no intentions of firing this experiment on the first starting load...you know..."Just in case!" I backed off 20 feet from this thing...then pulled the string!
It turned out 'uneventful', it was really a pretty mild sounding report.
Now I can do the benchwork from here...no more tie downs. I'll show you why in the next post with some more pictures...
These attachments below show the set-up in front of the chrono and bullet trap...Notice the chrono number? '1826 FPS'...that's awesome, thats 142,131 RPM ( @ 9.25 twist ) and that certainly will stabilize this round. "Fingers crossed!" Of course these cast are going to have to be cast as perfectly as I can manage for stability but this mold is dropping with a max. spread of 2 grains.