Fire Forming 300 Weatherby brass to a 7mm STW

[dakor]

I know I can neck down a 375 H&H case first by necking it a 30cal then to a 7mm and then fire form it. But if I wanted to save my self a step and wanted to use 300 Weatherby brass how would that work since it has a Double Radius shoulder? I know the bullet will need to be seated in the lands but what powder and what charge would you use?

 

[James Jones]

Well , I make 300Wby brass from 7STW and its a very easy step buyt as for making the 7STW from 300Wby , I believe that your gonna bin in for some headachs. The Wby case is a bit wider accross the shoulders than the STW so the case may cave in when its resized but you could just run the 300Wby case through a 7STW full elngth die and see what happens , it it doesen't colaps the shoulder then all thats needed is to be fired formed and for that I'd personaly use about 60 grains of 4350 and a long bullet seated into the lands hard.
NOTE : try some Imperial Sizing Wax , its awsome !!

What do you want to use 300Wby brass anyhow? I use Winchester 7Stw brass and sort it out and prep it and its just as accurate and alot tougher than the Rem crap or soft Norma

 

[dakor]

Well I use win brass now and it works well but I thought the Norma brass was supposed to be stronger and better quality I guess from what you are saying it is not true? Thanks for the info.

 

[James Jones]

The Norma brass is very high quality probably the best out their , its just soft and the cost is crazy , you can get the same results if your willing to work for them a bit with more durable Winchester brass.
If it were me I'd stick to the Win and just do match preping on your cases.
NOW , some time back PMC made some brass for the 300Wby that was super tough , its all been pretty much scooped up by guys shooting 300Ai's but you can run accross some here and their.

 

[Ackman]

Forming 300 Weatherby brass to a 7mm STW

A friend makes 7STW from .300Wby cases and it works well for him. He uses PMC brass which is very strong and allows good velocity. The only downside to PMC brass is, it's not sold anymore. BTW - when necking down, headspace tightly on the shoulder you've created...put the shoulder where there's a little resistance on the bolt handle. It isn't necessary to seat into the lands.