I've run into the know-it-all type, too. They can be hard to suffer. I've learned to just go along with whatever they say, and pay complements to their gear and their ways of doing things, then make my getaway as soon as possible.Good points.
Always willing to help someone out when humble but if they are already speaking as an expert based on their high speed gear I tend to turn away. I see a lot of the latter at my club. My time is limited there and I readily admit Im kind of anti social wanting to use the limited time to work on something I planned on working on. When I take a day of vacation and get to do it with the luxury of time different story.
Similar to you. 100 yard line. Guy had some species of .50. He had 4-5 five gallon jugs of water on the berm. He was about 2 of 5 hitting them.
When it comes to those cannons I hope there was a progression in caliber. Im not so sure though. Lots of people have the money and just decide such beasts can be handled without working up to them.
One of my favorites was the guy whose AR had a cheap scope on it where the crosshairs were so thick I couldn't see the "X" on his target at 100 yards. Poor guy, he was so excited about his shiny, new Barska scope that I didn't have the heart to say anything to burst his bubble. I just said, "that's really nice! Happy shooting!" and I shook his hand and I left.