Yes,

I had very good results with Federal Match ammo in 168 gr in that gun also. Had about the same results as you with the original factory stock. That broke in half one day after a wild ride on an ATV. I replaced it with a big Lone Wolf stock that I fitted myself and voila, the Federal ammo suddenly shot 1/4 inch, prone, off Parker-Hale bi-pod.

That shows that a good stock, and a good bedding of that stock, is as important as the barrel, maybe even more. I own a gun, a Strasser RS05, which shot absolutely awful when I got it (3 MOA). The barrel in that gun was a non-freefloating design, as you sometimes find it in Mannlicher style rifles. I made it free-floating at first by shaving off all touching parts of the stock under the barrel - shot even worse. So I came to the conclusion that this gun might need a supported barrel after all, but replaced the wood that I had taken off under the barrel with felt, which I glued into the stock in a way that resulted in a very tight press-fit. The idea was to support the barrel, but to let be in contact with a vibration-dampening material rather then wood. The result: 1/4 inch groups with Factory ammo (Hornady) ever since. Hence, this example shows that the stock, and how it interacts with barrel and action, is in most cases the real culprit if a gun does not shoot to its potential, and not the barrel itself.