Originally Posted by fourbore
I am having trouble finding certain powders for Hornady's listed loads for 300 JHP in 458 WinMag. Can I substitute loads for the 450 Marlin.

Specifically 50 grains RL-7 with 300 JHP with a goal of 2000 fps. Will I be safe and close to the money?


I used 60 grains of RL7 with the Hornady 300 JHP. I never shot them over a chrono but I believe I found the data in the Sierra manual.


Semper Fi