C'mon, Bill. I'd buy a 300 if I didn't have the 7.62, but really, there is little compelling reason for the 300. Using the 4:1 rule of thumb for velocity gain, you gain what? About 2 grains with the 300? That's 8% on a 25gr baseline load. So, that's a potential 2% velocity increase. I'm getting over 2,500fps with 125s and I've loaded some of my cases 3 times now. So, that's about a 50fps potential gain.
You don't need new cartridges to use different twist rates or throat geometries either. I'm just wondering what it's reason for being is. It's not easy or cheap to launch new cartridges. I just don't see what the payoff was for this project.
I assure you that you can't come close to 300 HAM'R velocity with the 7.62x40WT at the same chamber pressure. If you want to compare 7.62x40WT over pressure loads to 300 HAM'R safe pressure loads, then yes they can be very close.
Some of the loading data I saw is identical.
