Last bullets I tried were the Hornady 100 grain SP interlocks with a flat Base. I tried some IMR4350, with no luck. I also tried IMR4064, Varget, IMR4895, R22, H4831SC, IMR4831, Win748 (I believe) & Win 760. Not sure I had them all the way to the lands though. I used Hornady's called for seating depth. Maybe I need to revisit it with some seating changes. But that was early in my reloading career. Now having 25-06, .270, .260, and .308 that all shoot heavy bullets well. I doubt I'll ever change my 58 grain load, unless I need to eventually for the Kiddo.