Tim comparing a well worn rifle, in your own words that is, to a new one is hardly being fair or even really sensible regardless of make a lot of wear will be detrimental to any mecahincal items performance.
you might have been suffereing teh same ill that many target shooters fall into. their performance gets mediocre so they are persuaded or decide that their barrel is shot out so the either get a new rifle or a new barrel by one of the at the time in fashion makers and gunsmith and once they get it back their performance improves quite a bit which of course is solely laid at teh feet of the neww barrel and superior workmanship of the smith used.
When in fact what has actually happened is that they're now concentrating more and putting the effort in which they were not doing so before. How can I be sure you ask... Well consider this ............................................................. an old friend acquired several of these take off 7.62x51 barrels that were supposedly shot out so he selected one that best suited his plan cleaned the barrel thoroughly then fitted it to an old P-14 Enfield action then re-chambered it for the 300 Winchester Magnum cartridge. Using a handload that I developed when I owned the Ruger No1B in such a chambering which used the Speer 200 grain spitzer bullet that shot out barrel places five shots in about 7/8" at 100 yards and after proofing and finishing it went to Africa where it accounted for quite a few head of game and about 20 Baboons that were raiding the crops of the farm he was staying on.
So IF he original owner had cleaned the barre properly
and IF the target shooter had looked at himself rather than right away blame the barrel he would have saved himself a small fortune and most likely become a better shot in the long run.
An aquaintance here in Lincolnshire who belonged the the Reepham ranges brought a used Voerre in .308 which was a nice rifle if a bit light in .308 Win for a new shooter. As a result he found that his groups were not very consistant so after a short while he cam to the same conclusion as you and away it went and he brought a nice spanking new Sako 75 Finlite in .308 topped off with an equally spanking new Swaroski scope. he followed the vendors recomendation to break the barrel in religiously however his grouping was really not much better than with the old Voerre. he also found, although he was loathe to actually admit it
, the recoil when prone from the light weight Finlite rather punishing especilly with 165 and 180 grain bullets. His intention was to travel to Europe and take some Boar shooting which he did.
So he brought a Tikka T3 tactical which being much heavier he found more comfortable to shoot especially on the range and his grouping improved. Last i heard he was talking of swapping the Finlite in .308 for one in 7x64 or 300 Win mag in a sako 75/85 of normal weight. As I have not seen him for some months except to wave to as we passed on the road I have no idea if he followed through on this.
If he had learned his hold properly, stances, follow through and breathing the chances are that Voerre would shoot just as well as his expensive new toy. The Voerre even had a budget (Edgar bros) scope on it so it was hardly a fair comparision was it. The person who brought the Vorre it seems is very happy with it I hear and finding no problems with the grouping on target.