New Barrel questions

[saw]

I'm going to rebarrel my Rem 700 22-250 to a 250 AI. I'm thinking of a McGowen barrel in a 1-9 twist. It only comes in a 4 groove. I'm looking at shooting 75 gr Amaxs. I'm hoping for a 600 yard plus rifle, as long the nut behind the but is tight. My questions are from what I've seen McGowen barrels seem pretty good what are others impressions? Will the 4 groove barrel be good for what I am wanting? This will be my first long range rifle.
Thanks

 

[luke]

I have a savage with a 6.5-284 mcgowen barrel on it. It took less than 10 rounds to have a load that shoots 1/4" or less at 100 yards. The first time we streched the legs out it was at just over 1100 yards. With nothing more than an advertised bc and the velocity through the chrono it took 2 shots to hit an 8ish inch rock. The firt went high dailed down a few clicks and the next one was a hit. After shooting that gun a while I decided it was time to order a 7mm rem mag. Just a note they are running behind so dont count on it within a few months. Mine was supposed to be done in march.