Try the blue that is light blue an a 300 gr bullet for the 405 Winchester They work great in mine
How much BH209 are you using
Sorry but IMO he is full of it. The guy is plain goofy.
A 300gr 405Win bullet measures .411 and would be very very long in any 45x40 sabot. Your bore would have to be super loose just to load it. Loaded OD of the MMP tan is .456 with a .400 bullet. Loaded OD with either Harvester sabot is .454. Typical GM 45cal ML barrel grooves should not exceed .458-.460 at that most......The math don't add up.
Plus a 1-30 twist will more than likely not stabilize a 300gr 40cal bullet. Its too damn long. Call Hornady and get the bullet length then run it through a calculator.
Triple Se7en, if you knew anything about the Extremes, you would know they haven't made one in 45cal in many years. The old FPJ breach plugs were not the best for BH209. Been there done that many times.
The newer Lehigh type bare primer plugs have been 100% after more than 10 jugs of powder in no less than 7 Knight rifles from 45cal to 52cal. 155gr bullets to 375gr bullets. Not one hickup with a standard Win209.