Paul,

A while back, you expressed some interest in trying out my Mountain Molds 500 gr. .512" LFN-GC in your 500 Jeffery. If you're still interested, send me an email with your shipping address and I'll send the mold your way. The nose is only .400" long since it was designed for a revolver, but if you crimp it in the top lube groove like your heavy .475" it should just keep the top of the gas check in the case neck. What is your casting setup? This mold doesn't work well with my bottom-pour Lee, but should do fine if you're ladle-casting, or with the higher flow-rate of an RCBS bottom-pour.

Cannon