Is there any significant difference in strength or functionality between the old Vaquero and the new?
I know the old model is allegedly built on the Blackhawk frame and is larger, but is there any significant difference in what the two can do?
A point of order here, one pertaining to terms. There is a "terminology trap" built in to the names Ruger gave them, and people penchant for shortening names and misunderstanding.
At one time, it was reasonably simple, but today we have many variations of Blackhawk and Super Blackhawk, the Vaquero and the New Vaquero.
The NEW VAQUERO is the gun in current production. It is a fixed sight SA revolver of the same approximate size as the Colt SAA. The frame is marked "New Vaquero".
Always use BOTH words for this gun, and we know what is being talked about.
the VAQUERO is the larger, heavier, fixed sight SA revolver that Ruger produced before the New Vaquero. The frame is marked "Vaquero". It was built on the 44mag size frame. Call it Vaquero, or if you must add an identifier, call it the "original Vaquero", and confusion will be minimized.
If possible (and I know its not easy) avoid the use of the phrase "old model" when referring to the Vaquero.
"Old model and New Model" are terms specifically referring to the Blackhawk lockwork system. Ruger changed the lockwork (added a transfer bar and some other changes) in 1973. Blackhawks (and Supers) made before that are referred to as "old model" or "3 screw", by shooters.
Guns made after 73 are called "New Model" by Ruger. The frames say "New Model Blackhawk" or "New Model Super Blackhawk".
The Vaquero wasn't built until many years after the New Model (transfer bar system) change. There is no such thing as an "old model Vaquero" (a Vaquero with the pre 1973 lockwork).
"New" and "new model" mean different things to Ruger, and to us. It is very easy to use the incorrect term in conversation, and confusion can result.
I know the old model is allegedly built on the Blackhawk frame and is larger, but is there any significant difference in what the two can do?
In this case, calling the Vaquero the "old model" is pretty clear from the context, but this is not always the case, so I would recommend saying "original" or just "Vaquero".
and, to answer, the Vaquero is not "allegedly" built on the (new model) Blackhawk frame, it is built on the Vaquero frame, which is the same size (strength, etc) as the (large) New Model Blackhawk frame (.44 mag size, not the smaller "flattop" version.)
The Vaquero frame is essentially the NM Blackhawk frame but with a Colt style smooth topstrap and fixed sights.
The significant difference between the New Vaquero and the Vaquero is that the New Vaquero fits Colt size holsters, the "original" Vaquero does not.
The Vaquero can handle the top end .44Magnum level handloads. The New Vaquero is not considered safe with those loads.
The Vaquero can handle the top end "Ruger only" .45 Colt loads, BUT it is still a fixed sight revolver, and it can take a bit of work either in ammo, or in PERMANENT changes to the gun to get it zeroed with the heavy loads.
A (new model) Blackhawk in .45 Colt will handle the same loads, and is easily zeroed with a couple of screwdrivers. AND it can be rezeroed just as easily for different loads. The Vaquero (and all fixed sight guns) cannot.
This might not matter to you, but it does to me.
This should give you an idea of the difference between them. The top gun (blued) is a
New Vaquero 5.5" barrel. The bottom (stainless) is a
Vaquero, 4 5/8" barrel. Both are .45 Colt.
Note how, despite slightly over an inch difference in barrel length the guns are virtually the same size overall.