I did this test in my Match and wanted to see the Glock done. I'm going to watch with you and see:

Interesting video for sure!

The spreads are extreme, with 1494 0n one shot and 1353 on the next.

I had the slide lock back occurrence happen to me with the 165 TMJ's and a 22 pound RSA. Might be something to do with a hot loaded round?

Could it be bounce? He had a couple of issues there.

With a high recoil spring rate I wonder if you don't need to also up the mag spring to keep things in-sync. It didn't lock back on the last fired round either. Possibly the follower is wore or it's not springing up enough on the last round to grab the stop.