Great recommendation - recently, I did just that.
Used 55 gr M193 and 62 gr M855 ammo for both, and I couldnt tell much difference in accuracy between the two. 16 was slightly louder maybe, slightly more recoil and flash. Full disclosure though, we were using steel targets wed set up at roughly 200 and 400 yards - groups may have varied widely, no way to tell that day.
But afterwards I got to thinking, maybe 20 inch rifles are more of a luxury than a beneficial necessity, and so ... I posted here to ask the pros...
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