I bought a Mossberg 930 SPX and since none of the indoors ranges in my area alow shotguns to be shot I find an outdoor range that allows shotguns but the rounds must be slugs. I fire 50 rounds through it with only one FTF on the last round. I just wanted to get the feel because I have never shot or own a shotgun. So after I am done I want to fire my Glock 23 and try the 40-9 barrel and Glock 30 45-10 barrel. So I have to wait because the line is hot. When the line is cold I set up my target and when they say shooters lock and load and commense firing. I do. I empty one magazine, release it and load second. I am so into it all of the sudden the female range office taps me on the shoulder I put the gun down and she says your left thumb should be on the left side of the gun, not rapped around the gun over the bottom of your right thumb. The slide will hit your thumb. I told her due to my large hands I feel more comfortable with my left thumb over my right thumb. I try what she suggest but it just does not work. Rounds are high and right. I change and I am dead on. She walks by again and she interrupts me. She tells me to move my thumb to left side or leave the range. I tell her I am off when I shoot like that. She ask me to leave because she sees a injury in the making. I say are u serious. I understand what she was saying but I am off when I shoot that way. So I left. I was mad I just packed up and left. I am just venting. It started to rain hard so I was going to leave anyway. I didnt like the range because you have to sit on this stool to shoot our weapon and shoot through this 12 x 12 inch window. I rather be standing when I shoot.