That rim thickness gauge looks good, and at that price I probably can't make one for less. I have a couple dial indicators already. Hmmm..
The B14R managed a 0.6" and 0.7" @ 50yds today with the RWS Match (10 shot groups), zeroing for an NRL22 match. Well inside Bergara's accuracy limits. A bit of a storm front rolled by that had some evil wind gusts going on during the match, and I kind of suck at wind calls and aren't that good at building good positions yet - so I know I didn't shoot up to the rifle's potential. That's zeroing groups are about the results I can count on, if I'm not hampering the rifle from performing. I've seen smaller groups, but not often enough to think they're anything but luck. The T1X averages the same. Wish I could shoot as consistent as either rifle can.
Don't know if either is a match chamber, both are whatever the factory did. With both, if a shot goes wrong the rifles are good enough that I'm willing to assume I'm the problem. I do like having rifles where I trust the accuracy enough that if they miss, it was me that did it. You have a good point on whether my skills are really the limiting factor - I'm sure they are.
I feel the pain of trying to get a lefty Bergara, or anything left hand. I ended up with both the B14R and the T1X because I got impatient waiting months for the lefty CZ457 I ordered. My first attempt at getting the B14, the dealer sent the wrong rifle. By the time that was straightened out, that run of lefty B14s had sold out. Stumbled onto the T1X from another dealer, bought that and two weeks later the first dealer called me back with the B14 I wanted in stock. A month after getting that one, the CZ came in. I can't bring myself to move any of them on, because I can never bring myself to get rid of lefty stuff and will go out of my way to buy awful things because left handed.
As an example, I bought a Savage 64FL. Let me to be the first to admit, not a great rifle. Just barely hanging on to 'good' rifle status. Meh metal work, heavy creepy trigger, flimsiest of cheap plastic stocks, marginal iron sights. Exactly the price-point 22LR semi you'd expect it to be. Two things going for it: First, it does work. Acceptably accurate once scoped, or peep sight. Second, mirror image LH rifle. That alone was enough to send me after it, and even if it hadn't worked I'd have bought and kept it just because it's a mirror image left hand rifle. There's a twelve step program for this disease, and I'm endlessly repeating step 1.