I turned a M600 308 into a faux Chet Brown Mountain Rifle back in the 80s. Basically did all the work he did to end up with a short, light hunting rifle using one of his fiberglass stocks. Within a few months, Remington introduced its M7, which is essentially what I'd turned my M600 into. Later on, I replaced the turned down 308 barrel with a new 7mm08 tube.

An uncle gifted me with a M600 222 rem that had been neglected (before he got it) and had a fine coat of rust throughout, inside and outside. I cleaned it up as best I could, but it never shot well. I figured the bore had been compromised by the rust. At the time I was playing around with T/C Contenders in 7mmTCU and thought a caliber conversion would be a good idea, so I had it rebored and rechambered to 7mmTCU. To get it to feed correctly, I had to block up the rear of the magazine well a little. I now have a 'not-too-pretty' M600 repeater in a cool caliber that shoots light's out with 115 and 120 grain bullets. BTW, this was an early version that had the plastic rib, but it had been removed and the studs milled off. Because these barrels were so thin, I had to make sure the drilled and tapped stud holes would not be so deep as to compromise the larger hole diameter from the reboring.

My latest M600 is a Mohawk that came with a butchered-up hardwood stock. I ran across a somewhat less buggered up M660 stock, cut if off well short of std length, added a barrel band swivel stud, and sanded off as much of the excess wood as I felt comfortable doing, ending up with a slim, light, short walkabout rifle. The one on the bottom:

[Linked Image from i.imgur.com]