ICANHITHIMMAN
Well-Known Member
Is there a 7mm built on a 300 win mag case that is factory produced? If so what is it called?
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.
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.
I am in the process of having a 7mm rifle built based on the 300 WM case. This cartridge is not simply a necked down 300 WM though. The neck length is .284. I wanted at least a bullet diameter's length in the neck of the case. The diameter at the shoulder is .492 as opposed to .489 for the 300 WM. The length of the case to the shoulder is 2.183 as opposed to 2.196 for the 300 WM. The angle at the shoulder is 30 degrees instead of 25 for the 300 WM. The capacity of the case will be just a hair less than the 300 WM.
I think it will be a great case and so does Pacific Tool and my gunsmith George Vais.
Dies are being built by Hornady and will be done in about 5 more weeks. The reamer is being built by Pacific Tool and will be done in the next week or so.
Thanks for the information. I've considered the 7mm-300 Wby because it's far more standard than the 7mm-300 Win. but I have no experience with Weatherby cartridges so I kind of look at them the same way that I do a Macintosh. I have several questions about these?
Are the Weatherbys as accurate?
Are the case bodies roughly the same diameter so that they'll feed through the magazine without altering the rails?
Are the lengths of the cartridges roughly the same as the 300 Winchester so that I can seat the bullets out where they need to be instead of jammed into the cases?
How expensive is brass and does it last as long as other brass?
Do the double radius shoulders cause any trouble when sizing the brass?
Thanks