Elkhorn400,
As mentioned, the 3 groove barrels do offer longer barrel life but I would not say you will see much increase in velocity or decrease in bore fouling. If you break the barrel in completely and properly, very few match grade barrels have any fouling problems.
The 3 groove barrels have a well earned reputation for being a bit harder on thin jacketed match bullets. This usually is only seen when dealing with the heavy for caliber VLD or ULD bullets used in fast twist barrels at velocities over 3200 fps.
I have personally tested this in 22, 6mm, 257 and 7mm calibers. These were with 1-7 and 1-8 twist barrels.
In your case, I am pretty sure you are not using either of these twists and I would suspect you are using a 1-10 twist. That twist combined with the velocity potential of the 300 WBY with the heavier hunting and long range weight bullets will not present any problems at all.
You should get the full advantage of the 3 groove barrel and not see any of the issues I have mentioned.
I have fitted several Pac Nor barrels. Most shoot very well. I have had a couple problems with their barrels but they always corrected the problem in a very professional manor. They are not my first few choices for a barrel to be fitted for extreme accuracy but that does not mean they will not perform very well because most will shoot very well.
Kirby Allen(50)
