Just a note about the A-5 Magnum. I have one. It's actually in darned nice shape, but for whatever reason, I can't hit a darned thing with it (even when shooting a stationary piece of paper the pattern is extremely widespread, regardless of what choke I use). My dad was it's original owner - he gave it to me because he couldn't hit a thing with it. My uncle has one just like it with the same results. Several other people I know who purchased Brownings of a smiliar age also complain about this.
Now, mine is a Japanese model, made in roughly 1987 or 88. I've seen Belgian models that shoot well, and I've seen some of the later Japanese models that shoot well, but for whatever reason they seemed to let some duds go out the door in the mid to late 80's (can't complain about the functioning though - it goes band and cycles well every time).
On the flip side, my boss recently bought a brand new Benelli shotgun that was failing to detonate primers on half the shots it fired recently. They made good on it, but he was frustrated. My brother had a similar issue with a Stoeger which he was sent back and it came back better, but it's still snapping on a lot of rounds. It's darned hard to find a GOOD semi-auto out there these days, and it doesn't even seem to help buying high dollar stuff.