Indy
Now I may see part of my post makes sense to me.... but maybe bad to others.
First 1 inch at 100 rarely equals 4 at 400. IE most rifles are worse. IF you get 1 at 100 I"d be more willing to bet its like 6-8 inches at 400.
Hence the need for a better more accurate rifle and load. Sometimes once a good load settles in and stabilizes it won't as much as you think it should. IE its 2.5 inches at 200, at 300 its 2.5 inches. At 400 its 3-3.5 inches etc... Most rifles work the way I mentioned above though. So you have to get a good rifle.
And by being rebuilt-- I mean you can take a factory action and have about 400 bucks truing it up, and then stick on a 300-500 buck barrel, and drop it into a 500 buck stock and then if you don't know how to bed correctly can drop another 200 there etc....
Maybe that clarifies it a bit better.
Of course as noted by others, just because the gun is good, the shooter still has to do a lot of work and practice. To get decent at prone, I laid and dry fired my AR for at least an hour every nite till I got to where my muscle memory was good and things got better. But it came with the price of having to practice that hour each nite....
Jeff