It's possible ?

I have 100 one shot 7 rem mag cases and I will like to make them 300 wm.

It's just a "reload them with a light powder charge and a cheap 7 mm bullet" thing ??

Before anyone jumping why I just not change them for a bunch of original 300's remember I live in Uruguay..

Thanks

L

It can't be done......the 7mm Rem Mag is shorter than the 300 Win Mag case....

Thanks rembo, but that means that after firing it in the 300 chamber it will expand to 300 wm size ??

L

Try one and see how much neck you don't have.

the cases are .120 different, with the winmag being longer .. and with the winmag's ALREADY short neck, you would wind up with a neck .144 or so long ... as the winmag stock neck is .264 . about 3.5mm? more or less

in a survival/no brass at all situation, perhaps, but not by choice

Ok thanks guys.
I will not go that way.

Thanks again.
L

While they may be similar performance wise they are actually two very different cartridges, the case dimensions are smaller for the 7 MM RM when compared to the 300 WM.

You could set your barrel back and rechamber to .30/338 which will use the 7mm RM cases quite nicely. However, I suspect that obtaining regular .300 Win Mag cases would be more economical.

If you happen across any full length (2.85") belted magnum case like 8mm Rem, .300 H&H, .300 or .340 WBY, 7mm STW, etc., those cases can be run through a .300 Win Mag FL die and trimmed to make serviceable cases.