While not exactly the same these two cartridges are very similar. They have more case capacity than the 7mm Rem and not quite as much as the 7 STW. I've read claims that the Mashburn will deliver velocity well above the 7mm Rem. Is there anyone out there with first hand experience with the Mashburn or the 7mm 300? Thanks for any info.

I've loaded for the 7mag, STW and 7mmWby & 7mm300Wby. At equal pressure and barrel length there isn't but about 100FPS between them.

A 7mm-300wmag will only give you a couple grs of capacity over a 7mag. The 7 mag gets bad press as to velocity because it is loaded down to 61,000 not 64,700-65,000 like the STW & 7Wby.