Got a NOS 2 holer Lyman 225415 with sprue holes almost as big as the GC shank. This is a mid 1970's mould that weighs in,with GC installed @49g. Which is what I was searching for.
Not a newcomer to go-fast 22's. Have been scorching 223 and 22-250 barrels with cast for a few years. Absolutely zero complaints on accuracy,speed,or terminal ballistics(varmint hunting). Love the 55g Lee and RCBS moulds. Their sprue holes are noticeably smaller than this Lyman.
I could Tig up the holes(can do it blindfolded) but still would have to drill and surface them. Might as well start from scratch. Will make a few blanks to have on hand and spend a little extra time and design/build a drill fixture for repeatability.
Am going to start a touch smaller diameter than even the existing Lee/RCBS hole size. Also,go with a steel thickness more inline with the RCBS. The Lee is the thinnest,then Lyman,the RCBS is thicker yet. Will keep y'all posted on development best I can. Once things get rolling in the machine shop,I don't document very well. Finish the project and get right into the next layer of dirt(rabbit hole). It is nice,if you're into digging holes? to be using a big honkin backhoe vs a shovel.
Any discussion on plate thickness and hole diameter is not only welcome,but highly appreciated.