My current bush scope (haha I say that with the straight face of not currently being able to shoot anything bigger than a rimfire and also with the fact I do have options) is a 2-10x42.
The 2x is excellent for close range work, the light gathering and clarity of it is actually bloody good for the price point and it's not that heavy and bulky. 10x is good for the reasons others have mentioned, but one point of this debate that hasn't cropped up yet is the ammo selection is rather critical for a rifle application where you want to be able to shoot from muzzle distance all the way out. I'm comfortable with my skill point and current practice/proficiency level to take a shot on a static animal out to the 300m, and the rifle with the 2-10 on it is pretty close to the reticle hash marks which are 200, 300 and 400m.
The other points for a bush scope which are in my thought pattern more important than the actual magnification are the field of view, clarity, light gathering, eye box usability and the repeatability and accuracy of the adjustments and zoom ring. Another main one is the setup's fit for the shooter - height of the scope's center-line over the bore fitting the shooter's natural eyeline over the stock and also the clearance fwd-aft for focus and recoil clearance. Good light gathering in the bush can extend your shooting time to dawn and dusk limits which can be a substantial extra time for safe hunting and target ID over the mk1 eyeball.
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