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.
Thank you beretzs. That boosts my confidence. What velocity did Sierra show in the manual for 60gr? OK, I am reading a little closer. You may not have that manual handy. If not, no problem. I was thinking to up the charge to 55 or if the book shows 2,000 with 60, then I would load that. At this point, I am splitting hairs. I will flip a coin
If the 300gr bullets are not accurate, then I may try something a little heavier. My limited experience is the biggest variable for accuracy is the bullet. I took a chance on 100 of these Hornady. These days, I am lucky to find anything for components.
I would look to 3031 powder if you have any, slow that hp to around 1800 fps if you can safely do so, it'll still shoot plenty flat and penetrate better woed up a bit, it should shoot really well in the Great 458 Win Mag.
