I am looking at the M&P Sport II and the Ruger AR556. My purpose for the AR will be home defense and Coyote hunting. I have spent days and days comparing the two. I have one question holding me back from pulling the trigger.

After researching both guns the M&P Sport II is in front for several reasons. The issue holding me back is the accuracy difference (if any) between 100 and 300 yards with the 1:9 Sport II barrel and the 1:8 AR556 barrel. I can't seem to find any real world comparisons with accuracy and distance shooting for varmint hunting. I shot a few rounds out of an AR556 but didn't have any optics to test at distance. I am not expecting either AR to cover a nickel at these distances. I don't expect to shoot 70+grain loads. I just would like a comparison of these two guns or twists at distances I might shoot for coyote hunting. I am interested in knowing if the 1:9 M&P can shoot comparable groups to the AR556 1:8 when a satisfactory round is used. I am concerned whether the M&P groups will open up more than the AR556 groups at 200 and 300 yards due to the difference in the twist rate. My brother-in-law says I am overthinking this, which he may be right. His contention is that for the rounds I would most likely be shooting, 45 - 69 grain, there will not be a noticeable difference between the two twist rates. I cannot use an AR in 556 or 223 for deer hunting in my state so I would never envision needing a heavier bullet. I thought I would ask here as you guys seem very knowledgeable.

If not for the twist rate and accuracy at distance question I would already own the Sport II. I have had great success with Smith & Wesson firearms and I don't expect less from the Sport.

For the record I have other rifles. The decision on getting an AR is for home defense and to be able to coyote hunt with it. I consider my 22/250 an heirloom and enjoy shooting it. It is a tack driver, however, it is not a gun I want to beat through the woods, rain or mud.

Thank you for any input provided.