OK, here is the long winded explanation.... by putting in a buffer you have made shorter the distance the op rod handle can move backwards. The M-14 as with the M1 Garand design relys on the op rod and the rear of the reciever as well as the compression of the op rod spring to "Take up the shock" of the impact of the bolt moving to the rear. By making that distance shorter you are relying on only the op rod to take that force, at the roller bearing area. It is not designed to take that kind of force and will give it up way before it is supposed to. Now think about this, your bolt is in fast forward backwards and breaks right at the roller bearing area, if you are right handed, it takes off your right ear on it's way back past the reciever, if your left handed, well I think you get the point. Putting in a buffer excelerates wear it does not make it less. It does seem to lesson the impact and therefore the force of the impact but it is really just making your gun break sooner than it should. As for eating scopes, take a look at what the U.S. army had on thier XM-21's during the Viet nam war, just a cheap comercial hunting scope slightly modified for service use, any cheap scope made today is better than some of the most expensive glass made 30 years ago!! Perhaps you should reconsider your choice in glass. I know of shooters who have great luck with the straight 10 power 3200 series from Bushnell. With a good mount, say an ARMS 18, not a cheap copy of a good mount you should have a scope last and not be eaten.
Just my 2 cents, hope this helps by way of explaining.
Scott
