I'd like to convert my 300. Can I get by with a new bolt and rechamber job? I don't know if the 300 mag box has room, but don't care...single shot feed is just fine.

Thanks

Upshot,

Welcome. You are starting off great except we need to know what action are you interested in doing this to?

Regards,

Malm

Malm...Sorry 'bout that. It's a Weatherby MkV that I've hade since '70.

Thanks for the quick reply.

Erv

Will a .378 case fit into and out of the ejection port of your rifle now? If not, the port will have to be opened up.

I know of a .30-.378 Mk. V Synthetic with 123 rounds through it that's for sale cheap (it's not mine, it's another forum member's.

George

UpShot,

The multi lug Weatherby actions are not as readily changeable as are those of the standard 2 lug design.

You would be better off and money ahead looking for the correct action to begin with.

Good luck,

Malm

I have converted several 300 and 340 Mark V actions to 378 size cartridges. True, you would be better off trading for a factory 378 sized rifle. But, here is what is required:

Replace magazine box & follower, replace extractor, open bolt face, mill open the magazine opening in the receiver, mill out the bolt stop slot in the bolt, and sometimes, depending on COL, a little milling on the receiver so a loaded cartridge will eject. The labor and parts cost adds up fast!!!!!

And if you are thinking of rechambering a 300 Weatherby to 30-378, you need to consider both barrel length and contour for optimum performance of the cartridge and recoil management.

It's way cheaper to just buy one. You can get a Sako TRG in 30-378 for about $700.