I own and shoot Browning and Winchester ORIGINAL 71's (not that there are any other kinds). Any differences in weight are probably within the noise of manufacture (+- a few ounces). The few Browning '86s I've handled remind me of the 71's and I know I've shot original Winchester '86's (pre- light weights) that weigh more. I will say I've never disassembled either, so I can't comment on differences, if any, in their lock work.
As for shooting, you would be hard pressed to find a more accurate lever gun than the Browning 71 reproduction. 4" groups at 200 yards can be had with open sights (and that's as good as I can see).
