Necking down 300 Win to 270.

[HRM Johnny]

Very interesting thread. Thank you for starting it. Please let us know what you decide; and what the results are.

 

[Frank in the Laurels]

..not sure how long the throat or the barrel would last, that's alot of powder to burn in a .277 bore..might as well just make it a standard 7mm rem mag, .277 vs .284, no animal would notice the difference.. guaranteed.

 

[pacowboy]

I have a custom 7mm-300 Weatherby and inherited a 1960's built 6.5-300 Weatherby. When making brass for the 6.5 using .300 WBY brass I always use the 7mm die first in the resizing. Virtually eliminates crushed cases.

 

[Nimrod]

I sized .300 Winchester magnum cases to .257 Weatherby Magnum in a single pass and had zero issues. I would agree that neck turning would be required unless you go with a custom reamer.