The Harvester is a bit loose in my LK93 54 but the MMP is just right. My GMB54 is a bit tighter bore. Some of the older Knight 54s do have a slightly larger bore. Sofar the 300gr Scorpion PT Golds have been my favorite 54x45 but using a MMP sabot.

I prefer shooting 50cals though in my 54s or conicals. The 50A&E 300gr GoldDot Hunter with just 80-100gr in the LK93 is great and the GMB54 handles the hotter loads better. Its a great bullet at a good price.

I do really like my Barnes Original .458s though, they dont seem to ever fail and expand very well over a wide fps range. I just hate the price. Hawks Bullets offers a similar bullet for a little less.