In a letter from a man that shot against Bob Dalton before the Coffeville raid, he said they shot for a horse. Distance was 200 yards, they both used Bob's 1886 Winchester caliber 38-56, shooting was offhand, 5 shots each. The writer does not say exactly what size the "senter" was, but he said he was an uncommonly good shot for the day, tho Bob beat him. Sometimes by the width of a bullet.
I recall another reference to Bob's shooting that the writer stated that all the shots at 200 yards could be covered with a hand.
From personal experience with 1886's, and others experiences, with loads they like, 100 yd 2" groups are not impossible by any means, and some will do better.
1894's don't really fit into most the classification of an "old west" gun. The frontier was mostly civilized by the time the 94 came out.
I've seen a lot of old Winchesters, and haven't noticed more than a couple that were "loosened up" from carry in scabbards. Those that were loose showed more abuse than hard use. IF the stock loosens any, it can be easily tightened. The tangs pinch the stock, so even if the stock dried out or loosened, it can be tighened pretty easily.
I don't know that a Marlin would be stronger in a scabbard than an 1894 Winchester. They are both literally identical in stock attachment and tang, tho the 1866, 1873, and 1886 Winchesters have a longer lower tang with an extra wood screw, that would seem to make those models stronger than later guns.
I agree that a shotgun can be intimidating up close, but after the effective range is exceeded (40-50 yards generally), even a pistol is more effective. I still consider about any rifle or carbine and any decent caliber pistol to be more generally practical. Bows and arrows have more range than shotguns. The Indians were considered dangerous with them at an easy 100 yards.