Re: Steel Targets
I manufacture targets for several clubs and shooting ranges. I use AR 400, 450, and 500 (Hardox, Algoma, and XAR from Krupp). If you are stick welding a quality low hydrogen rod will work and remember to preheat. You can get by with 7018, but there are specialty electrodes that put 7018 to shame if you don't mind spending a couple of bucks per stick.
I prefer to use .045 wire in a pulse welder with 80/20 mix.