The AMT pistols certainly seem to be getting a bad rap, some of it deservedly, some, not so much. They did suffer some quality control issues, but they can be tuned up in the same manner as any 1911. I had one come in with barrel ramp overlapping the frame ramp. That should never have left the shop like that but it did. My personal hard baller looks identical to the one in the picture above. I have tuned it up and it feeds anything reliably. One of the main concerns with making a 1911 reliable is extractor tuning. It must be just snug enough on the rim to hold a dummy round in the hook. If it is much tighter than that, it will start to hang up rounds from moving up the breech face and the bullet may nose dive or hang in the ramp gap. The ramps must be cut properly, the breech face should be smooth and it doesn't hurt if the chamber is polished a bit either. Extreme polishing won't do any good if the geometry is not correct, some barrels have very little ramp as do some frames seem to have a short, steep ramp, that has to be corrected very carefully so that there is only the minimal unsupported brass area at the barrel ramp. Over ramp it, and you will have case blowouts down the mag well and end up missing a hand. Best to leave the ramping to a qualified gunsmith. Put the dremel tool down!
My HB shoots <1 inch groups at 50 feet from a rest. It is one of the most accurate 1911 types I have ever shot and I have national match colts, springfields, and custom built guns and it runs with the very best of them. You need to use good lube in the frame/slide rails and it should prevent galling, very light polishing may help with that too. I did exchange the extractor for a Gov't style one, it didn't break or anything, I just preferred that traditional extractor and it tuned up very well. I never got around to trying other barrels in it, mainly because it shot so well with the factory barrel I guess. When a barrel shoots very well, you leave it alone.