had something happen like this happen to my dad. there is a lake behind my house with a barge in it. well we had some 6 INCHers on it. and this was all wirelessly controlled well as he pushed the butten one of them blew up sinking the barge. if he would have been on it he would have been killed. all i can say is anything over 3in use wireless lighting or a long fuse.
Most states you have to be licensed to be in possesion of +3"ers, nevermind set them off. Most people think a 6" is just a double 3"er, but it's far and not, take great caution. Been a while, but if I recall correctly in CA you can't set off anything larger than 4" except in steel tubes. 4" and down is steel or high-desity PVC (oil/refinery industry grade). 2.5" and down is steel, HPVC, or cardboard. They define what materials you can use for the tubes based on that they can handle the round flowerpotting (pre-detonation of the entire round in the base of the tube, all at once). Then you have to take into account that not all mortar rounds are built the same or anywhere near properly, and that's why I haven't worked any shows in many years.
I got stuck on one show that had boxes and boxes of 7+ yo made in china 4"ers, 6"ers and 8"ers. We made fun that some chinese fireworks are so poorly constructed because they were made by single working at home moms, cooking dinner and breast feeding a child, while hand-manufacturing fireworks on the kitchen table. Well, this shipment we got stuck with must of been made, in the nicest terms I can think of, by one with 12 children and a very bad opium habit. They were labeled and supposed to be pre-squibed (electric squib ignitors), most were not and had to be hand squibed. Many couldn't be hand squibed because they weren't constructed properly (or falling apart), and it's a major fine to repack (manufacture) a mortar round in the back of a uhaul at the show site, but we had to for a couple dozen so we could put on a show (and afterwards those rounds were some of the few that worked as they should of). It was a nightmare when it came show time, ~60 out of ~170 primed mortars failed in one way or the other: breaches, flowerpots, duds, knocked-downs (one mortar in a rack of four would breach, knocking down or ejecting unspent tubes in that rack, resulting in grounded mortars or "duds" as they got ripped from their wiring harnesses). After playing a game of ballistic dodgeball, putting the fires out and the preliminary insurance papers filed, I told the company that if they ever would stick me in a situation like that again, to not call me, and they haven't since.
Largest mortars I've ever worked have been 10"ers at Dodger statium, and those were always fun, especialy setting off half the car alarms in the parking lot, and one night we assume the concusion from one of the 10"ers cracked the windshield on the rental truck parked over 100 yards away.
