Today for the first time I jumped at a firing range. I was at a nearby indoor range test firing a Glock .45, another first for me. Nice gun. I can see why law enforcement types favor it. I'm still a .357/.38 revolver guy, but I can appreciate the 13 rounds and the Glock fast reaction and safety features.
Each firing position is nicely separated from neighbor shooters by a concrete wall. Nevertheless, all of a sudden WHAM WHAM WHAM!, so much noise and an actual felt change in pressure and some smoke that I jumped. Just a little, but first time ever at a firing range.
When I looked around the wall, I saw a tall young guy with a big metal gun that looked like a lot of big military metal guns. He said it was a .50 caliber that he built.
Wow. It was a blast, literally. Didn't get any further details. Too much power for me. I went back to my comparatively tiny .45 Glock and then fired a couple .357 rounds from my Ruger Security Six for comparison.
Later I retrieved a .50 caliber shell casing. It's about the size of two .45 auto shells lengthwise and slightly wider, but nowhere near the size of a .50 machinegun bullet.