I had a Camp 45 for a while. I went through two stocks on it, and two buffer pads. It was still under warranty, so Marlin sent the parts to me free. I also replaced the recoil spring with a Wolf, but didn't keep the gun long after that. When I decided to sell it I removed the Wolf spring and replaced the original, because my brother has a Camp 9.
The gun does indeed get filthy, and in short order. I found the recoil to be unpleasant, too. The .45 ACP isn't that bad, but the bolt in the Camp 45 weighs almost a pound, and it slams into the rear of the receiver pretty hard. The gun also throws empties a LONG way. It is hard on cases, because it is a straight blowback. The cases swell during ejection, so much that I usually didn't get more than five or so reloads from them. The recoil also destroyed two different scopes for me.
Some, but not all, 1911 magazines work in it. There is some slight difference in the magazine follower on some 1911 magazines which causes problems with the bolt hold-open on the Marlin. You would have to look carefully at the real Marlin magazine and compare it to whatever 1911 magazines you want to use.
My Camp 45 worked just fine with brass ammunition. I seem to recall it worked OK with Blazers, too. But it refused to reliably feed Wolf steel-cased ammunition. There seemed to be too much drag on the magazine lips, best I could figure.