I need to open up my Win Mod 70 bolt to fit the 358 Norma Mag. (.531). Do I need to open the boltface to the exact rim diameter or a little larger?.

efryman,

Slightly larger.

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saeed@ emirates.net.ae

www.accuratereloading.com

Thanks Saeed,

How much larger?

Up to .538".

-Mike

Dave Manson Reamers have bolt squaring burrs which should do this joh, although you should check with them. The diameter they use for the magnum case head is .537in., and although it's expensive ($60), you might well find it useful for other projects, or find somebody to share it. I've never used these, but I've found Dave Manson extremely efficient and helpful for reamers.

http://www.mansonreamers.com

also, they are carbide and with proper use will last a long time.