I don't see a reason in the world why you would need a case gauge for your 10mm reloads. You have your barrels. Do you drop in test and move on.
Your load is hot. But not insanely so. My Hornady 7th Edition shows 180gn XTP Max at 10.1gn with a COL/AOL of 1.260. I keep my book loads at 1.260. My over book loads I set at 1.270. All shot out of my LW 5.15" barrel. I haven't shot a load one out of the OEM barrel / paper weight. And load them with Lee Dies. I would not load plated bullets anywhere close to that load. Is the outside of your case mouth's all black and sooty looking? I've seen 9mm and smaller auto cartridges not cycle a slide right because the powder was to slow a burn rate. Thus the brass was not sealed against the chamber wall and energy was lost.
The tab in the top of the slide has two functions. As the slide travels backwards after firing a round. It pushes the next round down slightly making sure there is plenty of room for the fired case to be extracted. The backwards travel also aids in making sure the next round is set back and set properly in the mag to be fed. Then the angled part on the face pushes down on the case rim and basically makes it pop out of the mag more so than pushing it out. The action of pushing down on the rim of the case and popping the round out is what wears out the mag followers over time.
To check the action on any of my weapons I always make up dummy rounds. I make sure the brass is clean. But not polished. I resize it and put a spent primer in these rounds. I then fill them to my powder charge weight with corn starch or what ever the wife has on hand in the kitchen. Then set and crimp the bullets. As a matter of fact I just used five of these rounds to check the function of my G20.
It's something simple or it wouldn't run at all.