Tight is good. The barrel fit is what keeps friction on that tab. If the tab is loose, so is the barrel.
Just push the tab forward with the baseplate of a magazine.
BTW, lock the slide back, first. When the slide is locked back, the recoil spring is captive. Then jam the lever forward and remove the barrel. Then hold the magazine over the spring when you release the slide. If you don't do it like this, the spring can pop out and get bent and/or fly across the room, cuz you have to partially retract the slide to get the barrel out and then when the barrel tilts up and out, there's nothing holding the spring down. To reinstall, do the same thing in reverse. Hold a magazine over the spring while locking the slide back. Then lock the barrel back in. (The frame mounted manual safety doubles as a manual slidelock, FYI).
The tab might be hard to get BACK into the locked position. You might be tempted to file down the locking nub on the barrel, a little. But like I said before, tight is good. One way to get it back in is to tap it in with a brass rod while the slide is locked back. You might have to bend the end of the rod a little so that it can reach the tab. It'll eventually loosen over time; no need to rush it. But be warned, if you don't get the tab all the way back, your gun can spontaneously disassemble while shooting. BTDT.