Do it enough, and the body adapts rather remarkably to weight being carried. If the only time you pack weight is hunting season, and don't spend a good deal of time on physical fitness, then yes, you might notice a few extra pounds. But, I seriously doubt that 2lbs is going to be the difference between making it up the mountain or not. If you are that out of shape, then you are going to hurt regardless.
BTW, the "light done right" rifle (Kimber Montana 7wsm) comes in at over 7.5lbs with scope and sling.
But the reality of it is that if you hike a bunch, with weight, then 2 pounds ain't much even if motoring up and down a bunch of hills. It's tossing that 80-120lbs on your back for the hump out that give you strain. If you can't handle a 8lb rifle, then you are really going to struggle with 100lb on your back for the pack out. And, I can't tell the difference between 100lb or 102lbs on my back.
My point being that light rifles are nice... if you can shoot them without needing a special rest or flinching. World of difference for me between shooting my 6.5lb 30-06ti with 155gr Scenar and 7.5lb Custom M7 7Saum and 162 amax. I am much more accurate with the 7.5lb rifle from all positions.
All true, unless you are a pansy like me, then I still want the lightest rifle I can get, since I can't shoot worth crap with a heavy or light rifle, might as well take it easy on my out of shape legs and hope I hit what I'm shooting at.
Truth is I can't feel the difference between 100-102 pounds either so I could get by with a 2 pound heavier rifle, and then I could get by with a 2 pound heavier sleeping bag, tent, 1 pound heavier sleeping pad, 2 pound heavier spotting scope, 2 pound heavier backpack, and before you know it you are 10+ pounds heavier than I started I can I feel a difference between a 90-100 pound pack and for sure prefer starting a week long trip with a 40 pound pack over a 50 pound pack. I'm of the mind if I can cut weight and still get it done just fine in all facets of the gear I put on my back I'll certainly take the weight savings regardless of the item put in my pack, rifle included.
