I had the same problem. Had to sand them down flat.
Update: I got tired of the tight draw and opened them up on the drill press. There was a distinct drop off in flavor as I went bigger. I like the draw now, but I lost the sweet tones from the bb, now it is a light cocoa. Huge vapor, though. So I guess be careful if you are going to go bigger.View attachment 372033
Yeah, to me, the draw on the RM3 (like the RM2) is part of the flavour characteristics that this atty puts out. I haven't drilled out the air holes for a look see myself, so thanks for posting your findings. If I want an airier draw, the RM4 is outstanding.