I got a Forster trimmer off the EE a while back, and got it setup for .223, trimming to 1.75. I trimmed quite a few cases, and then the next time I went to trim, I checked, and it was trimming about 1.745. I adjusted it, and now I am finding that it will go out of adjustment after 15 or so cases. It has gone as far as 1.735. I am also finding that some of the chamfering is way off, and some of the ends of my cases are trimming unevenly. At the moment, I don't have it mounted, I just hold it in place, and trim. I wouldn't think this would matter as everything should be adjusted and holding firm. My question is, do these trimmers suck in general, did I just get a bad one, or does having it mounted and permanently attached actually matter despite all adjustments being made?