Hello, everyone. In my quest to get a .450/.400 3 1/4" Farqharson talking again, I ran into a problem...The rifles groove dia. slugs at .411..I have Ideal 412263..300gr. with my moderate hard alloy & sized .412. The problem is Lyman doesn't make an M die for this caliber. I went with the .416 RCBS expander die & purchased extra plugs. I have polished these to .411, & .412...I can always make smaller if needed..the problem is that long 3 1/4" case..the RCBS die body is too short! No matter how shallow the die is threaded into press..the ram cannot reach top dead center.
I turned up some nylon rods that just fit into case mouth..adjusted length to achieve the right amount of flair on expander..when bottom of expander plug contacts rod inside case. Not fast..but it works!
Another possibility is the Lee Universal case expanding die.
I used to make plugs for the M-die but you have to cut the threads on the plug. The plugs for the Lee die are very easy to make, but you will need a lathe.
Nylon works. We had a grinder (for grinding brake pads - an extremely bad environment for grit) that used nylon pads to guide/align a conveyor. We replaced the nylon guides with Delrin - much greater wear characteristics. Both can be gotten with various 'fills' of teflon.
____________________ Chief of Smoke
Pulaski Coehorn Works
For .30 cals . If you have a RCBS bullet puller clamp a .311 bullet in the collet pointing down and it will open case necks for easy cast seating. You can see the operation and set the length as required.