Howdy,
This 56-50 project is a fun one.
Hear's an update & lessons learned. Had to relieve the under side of the hammer, it was contacting the frame preventing the firing pin from full motion & peening a spot on the frame, polished & cold blued the areas & I only know they are there because I know where to look.
Had to procure an over-sized chamfering tool for the case mouths, Lyman makes it.
My RCBS case trimmer won't handle the rims nor the diameter of the mouths. RCBS said their original hand-crank trimmer, model 9360, could be made to work with a conversion kit they sell. Got a trimmer on eBay & will get the 50+ conversion kit ordered next week.
Dillon says I cannot use any of their presses for this cartridge, rim size is too large. Loading is a single stage press proposition. The Lyman dies I purchased are working well.
Got my 512-350-T mould from Rapine last week. 2 cavity, aluminum block, very good handles (easy to grip w/o hand fatigue), LARGE grease groove. Casted bullets from Lyman No. 2, 20:1, wheel weights, radioisotope container lead (virgin lead + 4% antimony), made 20 of each. Weight is right around 360, lubed weight is 3 gr more (big lube groove). Sized them to .512 as were dropping from mould @ .513 - .514.
Had to modify the Lyman # 141 top punch recommended by Rapine, it was cutting into the bullet noses. Used the old epoxy trick & now it works great.
Made a case holder for annealing chucked into my cordless drill. The Starline brass is very hard, got blow back all the way to the rims on first firing.
Used some Elephant 1F for first firing with the 20:1, SPG lubed 300 gr. bullets I to from Buffalo Arms. If I wiped the bore after each string of 7 shots, there was no leading. With proper light conditions, I was able to hold 3" 7 shot groups @ 100 yards.
Sights on the gun are not conducive to accurate shooting. Best sight picture is bottom notch on the raised long-range sight, hits about 8" high @ 100 yards with a bottom hold. Might replace or rework them at some point.
Next steps:
Anneal the brass.
Try with Schuetzen and Swiss 2F, can't get Elephant 2F any more as what was left of Elephant powder is disappearing fast. Won't mess with Goex at all, it has alwlays caused excessive fouling in my opinion.
Trim the brass.
See which alloy works best.
Get a second set of main springs & work them down. Trigger return alone has a 10 lb pull!
Maybe mill a slot into the front sight w/hole for roll pin. Maybe get a ladder sight from Smith Enterprises.