Welcome to the Forum
Possibly you are having trouble because 2400 may not be a good choice for that cartridge and projectile weight.
In 4 decades I have never used 2400 so I will not be much help
I have gotten the best results with my 510 grain wadcutters using AA1680. You can load 46 grains and not exceed pressure limits (getting close) while the projectile hits around 1700 FPS depending on which barrel length you are firing.
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