TC, do u know what the twist rate is in your barrel? If they're saying that the 55 is the highest generally that will stabilize, i'd bet 1 in 14" maybe.
The original poster said "long-range" which is why i detailed my experiences with the JLK Low Drags. When i shoot at long-range with my rigs i like to have every possible advantage i can get which is why i shoot the LD's. I happened onto them several years ago when i was looking over Jimmy Knox' catalog, and when i saw their BC's it immediately grabbed my attention. I've read about a lot of guys using the Berger's as they have better BC's than the factory bullets offer, but the JLK's are a step beyond them even. Jimmy sold the business to Steve "Swampy" MilHolland at Swampworks, right here--
http://www.swampworks.com and he isn't producing the 52 Low Drag anymore for some reason? Here's the stats on them--
52 (14 twist), BC=.302
60 (12 twist), BC=.339
65 (10 twist), BC=.395
Just about every 22 i've shot them out of gave better accuracy than anything else too.