Not a Bergara B-14, but I’ve had half a dozen Manners stocks (using their mini chassis) and 1 or 2 needed a slightly shorter mag latch. I tried 5 or 6 mags, and none of them could seat. If you contact manners, they will send you a few various length latches to try (I’m just assuming you have their mini chassis). Or as said above, you can incrementally file down your existing latch.
First though, it might be good to check with a few different mags to make sure it’s not a mag problem. I had a P-mag AICS-L that was molded poorly. All my metal AICS & accurate mags latched fine (different stock than the ones mentioned above), but that one Pmag wouldn’t work.