My Thompson 1927A1 is not holding its mags secure enough and I am getting an occasional jam. It is not a mag problem and probably requires a little latch work. Usually I do this stuff myself but the Thompson's guts are a little more complicated than your basic AR or AK. I contacted a gunsmith and he would not give me an estimate on the latch replacement until he could look at the gun. That is fine but he said he was going to charge me for his time to look at the gun and give an estimate. In your experience, is this common practice? I have never paid for an estimate on anything. Anyone have a good gunsmith???