Tidesout, you stated your rifle has a scope, does it have a sporter type forend? If it's still in full military trim there's a lot more to consider when setting the barrel back. Your gunsmith will have to determine exactly how much he will need to remove from the shoulder to get a full turn or two, it has to be exact or the sights will be off to one side. In doing this you are shortening the barrel from rear and this will through off a lot of critical dimentions. As stated earlier, light short bullets very seldom work well in military rifles because even a new barrel will have a long throat. When the manual says a certain load will produce a certain velocity that does'nt mean all rifles of that caliber will produce the same results, thats just what the test rifle achieved. Some rifles have ''slow'' barrels for some reason or another. Have you slugged your bore to determine the diameter? If it's oversized and the bullet does'nt ''fatten up'' to create a seal then it will have blow by and velocity will suffer as a result so setting the barrel back won't solve the problem. Like Brian said, rebarreling would be a better option.