Excellent photos, looks like a fun time.
Congrats on your new mortar! Peer pressure is a terrible thing!
As far as fire & smoke pics, does your camera have a video mode?
I've never managed to get decent photos with the shutter, the fireball is there and gone so fast that timing it right is virtually impossible (at least for me). Instead I shoot in video mode and then select individual frames from the video. The result does not have the resolution of a still picture, but I'd rather have a small photo than a missed shot.