Last year I converted all 3 of my Knights(.50 cal LRH, MH and Disc Elite) with their new bare primer breech plugs and replaced the bolts with adapters with the new Mountaineer style bolts. I had a lot of trouble with both seating the primers and even more ejecting them. On one I couldn't even close the bolt completely. After talking to Knight and others I decided to polish the primer pockets on the BPs using Western Powder and JB bore paste and baby q tips from CVS. It took a few nights to slick them up and I have had no problems since. I use Winchester's regular 209 primers and have minimal blow by with up to 105 Gr loads of BH209. With 110 to 120 grs of BH209 the blow by increases a bit. I also have 3 bare primer BPs made by Lehign before they contracted with Knight from a clearly different alloy and have never had an issue with them.