Here's an update: I'm still alive, first of all, not on rocket to moon.
First, I filled the tank with water thru the bullet hole, after struggling and failing to twist off the main valve (photo). Then, I plugged said hole with piece of bike rubber tubing. Then, in about a minute, I hacksawed off main valve (much easier than struggling with it!). Then, with tank full of water I used a metal cutoff wheel 4.5" on my cheapy HF angle grinder to grind off the top. It will be a while before I do anything else. I believe the way I proceeded was the safest. I could sure smell propane for days, even after filled with water. It's probably not a job for feint of heart. BTW, if you look carefully in the last photo of the tank open you can see the spent bullet. It only went thru the bottom. Also, I unscrewed that thingamagig, which was on pretty tight.
First, I filled the tank with water thru the bullet hole, after struggling and failing to twist off the main valve (photo). Then, I plugged said hole with piece of bike rubber tubing. Then, in about a minute, I hacksawed off main valve (much easier than struggling with it!). Then, with tank full of water I used a metal cutoff wheel 4.5" on my cheapy HF angle grinder to grind off the top. It will be a while before I do anything else. I believe the way I proceeded was the safest. I could sure smell propane for days, even after filled with water. It's probably not a job for feint of heart. BTW, if you look carefully in the last photo of the tank open you can see the spent bullet. It only went thru the bottom. Also, I unscrewed that thingamagig, which was on pretty tight.