7x57 Mauser bullet mold

 I appreciate the responses. The update and back story: I have an early '80's Winchester M70 XTR Featherweight in 7x57 Mauser. Never intended to shoot cast in it as I have literally thousands of jacketed bullets in .284" . Full power jacketed bullet loads will leave the fired case neck with .292" ID measured with a pin gauge. There is .285" length free bore in front of the chamber neck before the rifling starts. I partially resized the case neck with just enough tension to hold the .292" pin gauge snug but still push into the case when chambering to get free bore measurement. The bore/groove measurements are .276"/.284". With LBT burning down it wasn't looking good for 7mm molds. Accurate Molds has tooling limitations for 7mm like no gas check and very shallow lube grooves, NOE is out of stock of any mold I ever need, and I really didn't want to get a single cavity custom spec Brooks mold but I was leaning that way and still might. I found a used (?) RCBS 7mm-168-SP two cavity with Omark Industries on the box at the LGS, probably late '80's -'90's production. It didn't look used as it hadn't turned that slight purple color from heat but it was on the used shelf. The price was half of what they go for now so I bought it. Cast of wheel weights it drops .287" on the driving bands and the bore ride nose is .280". Now I have to deal with nose sizing the long bore ride section down to .276". I have my own lathe and mill but since I use machine tools for a living I really don't like coming home and building things. In this case I had no choice. I made a .288" Lyman style H&I die for the body and a .276" die to nose size. Pushing the bullet into the die to nose size increases the bullet diameter by .0005" to .2875". Nose sized to .277" it will stick in the rifling and will pull out of the dummy case staying in the rifle when ejecting said round. While building the .288" H&I die I stopped @ .276" and then .277" and tried that nose size of each in dummy rounds and found that the .277" stays in the rifling when loaded to 3.1" OAL. Initially I thought I was going to have to put the RCBS mold in the Bridgeport and use a boring bar to open up the driving bands in the cavities. That was before I cast up some samples and found out about the big nose size. But now I'm hoping that the custom sized bore ride nose will center the case/bullet in the bore and accuracy will be good. I'm chasing turkeys right now here in MO so I won't be able to test it for another couple weeks as I don't shoot on the farm shooting range when season is going. The toms like to strut on the low cut grass of my range.