So, took the re-assembled kaboom gun to the range to re-zero it, and put the new TRS-25 on an AR pistol. The whole process of removing the scope, removing the barrel, getting the stuck round out, and reassembling...and I was about 1/2 inch off zero at 25 yards. Not too bad. Didn’t go longer range, because the next thing at 25 yards was a pain. Started zeroing at 25...and it was ugly. I’d get it close, then things were off again. 15 rounds, no joy. So I moved closer, same problem...and then I noticed the front lens was sticking out the front of the tube, the O-ring was showing, and I could (and did) push it back in with my finger. Shot a few more, and the thing is starting to walk out again. So I shut it all down in disgust. But then I remembered the other gun was great, and the brand new Caldwell brass catcher had worked just fine. It’s the “Brass Trap”, you can set it on a table, a tripod, or wherever. So much nicer than hanging it on the gun.