Quoted:
Try a full range of bullets, at various distances (50, 100, 150, 200, 200+) with your barrel before you go swapping.
You may very well be surprised at what stabilizes in your barrels.
So far, I've honestly been very impressed with 1/9 barrels the most for accuracy with cheap ammo. 1/8 stainless seems to really shine with the heavier stuff, but each barrel is different with the heavier loads.
+1
Most nowadays' want the 1/7 because it's whats hot these days. I can't afford to consistently feed a 1/7 barrel the high-dollar-ass ammo to get any real world benefit.
A 1/9 twist barrel will shoot a broad range of ammo just like 1/7 will. Only difference is a 1/9 will shoot from light to medium weight bullets best, and the 1/7 will usually prefer the medium to heavier weight bullets (I think it's actually a little more dependent on bullet length). Just because the 1/7 is currently all the rage does not make a quality 1/9 a dinosaur.
I agree with DanTSX. The 1/9's really seem to get you better results with the cheaper 55-62gr bullets than most 1/7's. Of course this is just a personal observation and not concrete. Barrels of all twists will vary widely with the ammunition they prefer. I refuse to believe that a 1/7 is superior because it's not, sorry. It will be superior for some and not so much for others. Depends on what the guns primary purpose is as to which will be best for you. If I could afford to shoot a bunch of 69-80 grainer's I too would probably opt for a 1/7.
I actually want to try a .223 Wylde chamber with a 1/8 twist. I hear they are supposed to be very versatile, although I have no firsthand knowledge to verify that.