Here's a chart that shows optimum twist for bullet weight. I found it on here (posted by Axe I believe) a while back. A lot of companies are making 1/7's now, but just as many 1/9's. I have a 1/7, a 1/8 in .223 Wylde chamber and a 1/9. My guess is you will never shoot heavy enough loads to optimize the 1/7. My 1/8 is a tack driver with 55 grain loads. I hand load 40 gr varmint rounds, so the 1/9 is the ideal twist for those.
Unless you are trying to shoot the wings off if a fly then you should be able to achieve pretty reasonable accuracy with any of the 3 twists.
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