If your chamber is clean, allowing consistent seating depth, perhaps the 'transfer rod' is 'dragging' inside the bolt. Have you ever taken the bolt apart? My B22 bolt had a bunch of cra* inside, manufacturing debris and 'drying grease'. I propose the inside of the bolt should be pretty dry, maybe a spray of Silicone dri-lube allowed to dry before assembly. And the firing pin itself should NOT be oiled, that could gum up or at least drag in the channel.
Here's a link to Jim's "YT vid on bolt disassembly -> https://www.youtube.com/watch?v=28LkXjzrFgo