So, the question that I have to ask myself is: what does a .460 do from a T/C Encore with a 15 inch barrel that a very hot .45 Colt doesn't do from a 16 inch 1892 Lever action rifle?
leaving aside all discussion about the difference (if any) in the power of the rounds, the T/C is built to give you one
precision shot, at a time. The lever gun is built to give you a magazine's worth of
reasonably accurate shots. And, reasonably accurate is being optimistic.
And there is more to it than just the sights. There is the trigger, the barrel, and the overall construction of the gun, as well.
Several have mentioned the sights, and how a peep sight is more accurate than the usual semi buckhorn open sight. The peep is easier to use, as it relies on the eye's natural ability to find the center of a circle. Faster?? that depends on the shooter, and the size of the peep sight aperture. Peeps with a large hole (aka, Ghost ring) are very fast to use, but more difficult to use with maximum precision. The small hole in target peep sights is very precise to use, but can be difficult to find in a hurry, or in lower light situations.
Scopes? (or dot sights)? Easy on the T/C, and on a Marlin lever gun, but not so much on a Rossi (Winchester design).
The top ejecting Winchester design means that a scope must be either the long eye relief type, mounted forward of the receiver (Scout Scope style), which is not for everyone, OR its mounted on the receiver, either a side mount, or a mount on the side of the receiver that puts the scope high enough over the action so the fired brass will eject properly.
Neither of these side mounts is easily usable with the factory stock.
Something not mentioned before is the trigger. The best sights in the world won't give you their best if the trigger is crap. I will admit to no personal experience with the Encore. I do have a couple decades experience with the Contender, and it has an excellent trigger. And mine (older guns, don't know about the newest ones) have adjustable triggers.
Also, no personal experience with the Rossi, but I have experience with a number of lever guns, Winchesters, Marlins, Savage, and their triggers run from horrid crap up to decently usable, with rare individual rifles being better. NONE of them have a "target" type trigger pull, which the single shots often do. A good trigger job can improve them a lot, but they don't come from the factory that way.
And then there is general construction. The lever gun, with a tube magazine, and barrel band means that there is a lot more going on to affect barrel harmonics than there is with a single shot. This means the single shot
tends to be more accurate when shooting groups. individual exceptions do exist.
I see I'm a little late to the party, and you have made the choice to go with the new single shot when it comes out. Total unknown to me, please let us know how it works for you, after you get it.
I am curious, why the Encore, and why the .460?? to compare to a Rossi 92.
Different things for different uses, in my book. I can see the Encore, if you're looking to use a .308 (later), and .460 because it will take .45 Colt ammo. But comparing a single shot with a lever action repeater, even in the same caliber is not an apples to apples comparison.
'Bout the only problems I hear of (but have not personally experienced) are with Keith styled semi wadcutters, that have a sharp front driving band (originally designed to scrape black powder fouling outta the bore).
I have had feeding issues with SWCs in Marlin .357s, but never in .44s. The way you work the lever seems to be as important as anything, when shooting SWCs. RN and jacketed feed like water.
Never had a .45 colt lever gun, so can't say for certain, but it seem unlikely. This is the first time I've ever heard Keith type slugs were designed to scrape black powder fouling out of the bore. Everything I've read, for decades, including from Keith himself, always said he designed the sharp shoulder on his slugs for maximum shock on game, and they cut nice clean holes in paper, as well.
