What about primers being wet? I had been canoeing all day then hiking through the snow everything in my pockets were sweaty, but not soaked. Maybe that combined with the regular CCI primers not the magnums? I have no idea either like I said every failure I’ve had before was wet pellets or clogged breach something obvious
Don’t know if you ever figured this out but it seems odd that you would have that issue. Blackhorn has always been reliable for me and my buddies. We all shot the CCI 209M shotgun primers though. Blackhorn does state these as the only primer to use. Well, those and I believe Federal magnums.
I would bet that the primers arent hot enough to get reliable burn on the powder.
If you can find the 209M give them a shot and see if it fixes the problem. If it does just buy 10 boxes of primers. They are cheap and easy to store.
I have never had misfire with bh209 either. I was using Winchester w209 primers for several years with no issue. This summer I decided to change loads and went with Barnes Tez and also moved to the Cci 209m.
I could not get groups with the new load and my POI went down with a hotter load and same grain bullets. I switched back to Winchester primers and the groups tightened and POI went back up about 4 inches. This is in a CVA Accura V2.