Phoenix Up + Silver Bullets = obscene damage to jammed bosses apparently

At least I'm pretty sure that the Silver Bullets were the key ingredient. I had the jammed >!Dragun's!< first phase down to about 75% when the Phoenix Up familiar shot it, ending the phase immediately. Then it happened again on the >!Lich!<, he was jammed in the third phase and the phoenix shot him when I had done only a little damage, killing him instantly.

I also had +1 Bullets but nothing else affecting damage (except the Convict's photo, but I'm not sure it was active the second time, and definitely wasn't the first time because I got the Master Round). So that's +225% for a jammed enemy, +25% for a boss, +25% for +1 Bullets. That little bird's base damage must be pretty high.