This may not be new to you but it sure is a welcome discovery to me! I am getting organized to cast bullets for a made in 1905 Winchester Model 1905, in caliber .35 Winchester. This rifle takes a .351-52" diameter bullet. Problem is the bullet in my rifle needs to be sized to .3515". Ever try to find a Lyman H&I die in .351" diameter? Again I lucked out! I was gazing thru Buffalo Arms Company's website and I did a random search on that site for an H&I .351 sizing die. Up came a photo of just the die I was looking for---made by Buffalo Arms! They have about 90 (!) other odd sizes that are available and pictured. Most of them are in stock. Cost of the dies, produced by Buffalo Arms own CNC machinery is $48 ! It took me about 2 minutes to order one!
Just wanted to pass this tip along and I hope you find the odd-sized diameter you are looking for.
GregT
Hayward, Wi