NateCowlishaw:
The original Ruger "Vaquero" (sometimes called by people around here the "Old Vaquero" was built on the 44Magnum-sized frame first seen in the 1973 Blackhawks/SuperBlackHawks.
That "Vaquero" can handle any load the other large-frame guns can, in 45LC or any other caliber.
There is a new "mid frame" size class Ruger that cannot handle 44Mag ammo or 45LC"+P" of basically similar horsepower. This "mid frame" is similar in heft, size and strength to the Colt SAA 2nd or 3rd gen, or the various clones of same you've seen in this thread. Or the various USFA sixguns.
SO FAR this new mid-frame has appeared on two guns:
* Ruger 50th Anniversary 357Magnum Blackhawk (always blue, adjustable sight, 4.68" barrel).
* Ruger New Vaquero (various barrel lengths, stainless or blue with fake case color frame, 357Magnum or 45LC).
The New Vaq in 45LC is the ONLY Ruger 45LC factory gun that cannot take "Ruger ONLY!!!" ammo by Buffalo Bore, Doubletap or the like. This gun should be fed ammo marked as compatible with the Colt SAA 2nd/3rd generation although it's possibly just a hair stronger.
Adding to the confusion: you'll see references to the "50th Anniversary Blackhawk" being on the mid-frame. That was true until the 50th Anniversary 44Magnum Blackhawk came out which combines a larger primary frame size with the SMALLER grip frame size of the New Vaquero and 50th Anniversary 357. In other words, it's a "hybrid". A GOOD hybrid. Also the ONLY 44Magnum Ruger single action that does not bear the word "Super" before the word "Blackhawk". Same gun Franco2shoot posted above, damned fine piece.
If you want a large-frame Vaquero, they are discontinued but still pretty common on the used market. Prices are rising though on many calibers, especially 45LC. 357 and 44Mag, not so much unless they're one of the special-run multi-caliber sets (357/9mm, 44Mag/44-40, etc.). There was a 38-40/40S&W convertible special run Vaquero that's probably worth decent coin now. "Bisley Vaqueros" will be worth more than plain "Vaqueros".
I think the New Vaqueros are better-built guns and have detailed that on other posts on this subject. I suspect most people are better served with the new mid-frame series so long as they don't need more power than the 357 can deliver, or in 45LC a 255gr lead slug doing 1,000fps or a 200gr JHP at 1,100.