I am sure this has been discussed here before, I even seem to recall reading about it, but I'll be darned if the search function is helping me find those threads. So, I'll ask again. I picked up a used Remington 870 Wingmaster, 1974 vintage, a few years ago. It was a bit beat up and had some surface rust, but the wood looks really good (old Remington wood) and the action is as smooth as you would expect from an old Remington. I'm gradually working to clean this gun up. The barrel was pitted, so I am simply replacing that. The rest really needs a thorough cleaning and I may just get the receiver/mag tube Cerakoted to clean it up. Here is my question, the new barrel will likely be one that will accept both 2 3/4" and 3" shells. The original barrel was only marked for 2 3/4" shells. The receiver serial number does not end in "M", but rather in "V", so I know from Remington it's meant to be a 2 3/4" only receiver. That said, I've done some poking around on the internet (dangerous I know ) and found more than one instance of folks saying that really the main difference between the "M" receivers and the non-M receivers is a different extractor. I've also read that the barrel/chamber is really what determines the strength/safety of the gun with respect to which shells can be fired. My question is this - is it possible to safely convert a non-M marked receiver to use 3" shells, in combination with a proper 3" marked barrel, by replacing the extractor? Or is this just a bad idea? Is the 'strength' of the receiver any different in a 3" gun? Since the barrel/chamber really is what contains the force of the shot, it just seems to my untrained non-gunsmith self that as long as you have the proper barrel, it might be a possibility. It's not critical to me. If the gun needs to stay with just 2 3/4" rounds, I'm fine with that since that's primarily what I shoot. I just happen to like versatility in my guns, so if it can be safely upgraded to also shoot 3", well then that's just a nice extra. Regardless, safety is #1 for me, so if it's unsafe to make such a modification, then I'll stay far away from it. Thanks!