300 win = what in 7mm

[ICANHITHIMMAN]

Is there a 7mm built on a 300 win mag case that is factory produced? If so what is it called?

[yellowjacket]

That would be the 7mm Remington Mag.

[James H]

There are no other factory cases based on the 300 Win Mag.
The 7mm Rem Mag is the 338 Win Mag necked down.

James

[MagMan]

the 300 WM is considerably longer (.156 in body & .12 OAL) than a 7mm RM.

The real answer is "no"

[cross]

No, it's not a 7mm Remington Magnum. I have one of those and have been investigating getting mine bored out to a 7mm/300 Winchester (7mm-300 Winchester). BTW, a 7mm/300 Winchester is pretty close to the original (or at least the most famous of the originals) called 7mm Mashburn Super Magnum which was made famous by Warren Page. (If I don't have the Mashburn Super Magnum part right feel free to correct me, there were several 7mm Mashburns and I may have my facts mixed up).

My opinion is that a 7mm/300 Winchester would be a fantastic cartridge that would come close to splitting the difference between a 7mm Rem Mag and a 7mm STW capacity wise and would provide velocities closer to an STW than the standard 7mm Rem. It would also allow the case capacity to be expanded while keeping the OALs short enough to allow bullets to be seated to the correct length in a standard model 700 magazine box and provide access to all of that wonderful match grade 300 Winchester magnum brass.

If anyone knows a gunsmith that has a reamer for this and/or can provide me with more information on where to get dies for one of these it would be greatly appreciated.

[blygy]

I have a 6.5X300 Win Mag.. Redding was the supplier I used.. It was recomended by my smith. Just make sure they get the Win Mag part right.. My first dies were 6.5X300WSM.

Now I just need some time to build a load.

[rocky_lange]

Originally Posted by cross

My opinion is that a 7mm/300 Winchester would be a fantastic cartridge that would come close to splitting the difference between a 7mm Rem Mag and a 7mm STW capacity wise and would provide velocities closer to an STW than the standard 7mm Rem.

There already is a cartidge that splits the difference between the 7 Rem Mag and the 7 STW. Its called the 7mm Weatherby Mag. No specialty chamber dies needed. Reloading dies are readily available. Norma makes the brass.

Want something more powerful than the STW? 7-300 WEATHERBY Mag. It has been out for a while so reamers and dies should not be hard to find. Again, Norma makes Weatherby brass.

Do I have a thing for Weatherbys? You bet. Roy Weatherby knew what he was doing when he developed his cartridges.

Rocky