Hi guys, my first post. Great looking site! My Win M70 .300 Wby's barrel just about cooked. Instead of another .300 I'm thinking about a .416 based on the .300 Wby case. Basically a necked up .300. Why? Because I've got several hundred rounds of brass and just can't justify the need of a couple hundred fps over my '06. Im sure this isn't something new, but I've yet to track it down. I'm pretty sure the .416 Wby is based on a larger case, the .378 Wby? Thanks everybody.

Cain,

A 300 Wby necked up to 416 would be basically the 416 Remington.

Your best bet would be to rebarrel to 416 Remington. You neck up your 300 Wby cases. However the Wby shoulder collapses very easily so you might need to go throug 338 and 375 and then finally to 416 and with plenty of lube on each expander plug.

Use 416 Rem dies. Load up the necked up cases and fire, and you have a 416 Rem with 300 Wby written on the case head

The cases will shorten in the necking up process.

Mike

Mike's right about those Weatherby shoulders collapsing easily. You might have better luck fireforming with Bullseye and cream of wheat.

Thanks guys. Sometimes the answer is so simple you completely miss it. I was thinking, keep the radius shoulder, but reforming to a straight .416 Rem makes the most sense. Thanks again.

Cain. There will not be much of a radius left when you neck the brass up to .416 - the shoulder is just about .02" wide.

Does anyone know if the 416 Rem can head space on the shoulder? That would prolong case life significantly. AKI

Once the loads have been fired once, then neck or partially resized only, they should headspace on the shoulder. - Dan