The ones Ruger is offering now are built on a medium frame, it is a fairly recent re-introduction of the medium size, which was dropped from production when the New Models were introduced.
And yes, before Lipseys, most folks were building them on medium frame OM .357s, which ends up being lighter than a Lipseys because of the aluminum grip frame (Lipseys is all steel).
Just to clue you in a bit more. Prior to the NM introduction there were two sizes of OM centerfire frames, medium for .357 and large for .30 Carbine, .41 Magnum, .44 Magnum, and .45 Colt. There were never any factory poduced .44 Specials in any OM, regardless of size.
When the NM was introduced, they decided to base ALL centerfires on the same large frame. There was a great deal of grumbling from the troops over this, as it made the .357s pretty big in comparison to the medium OMs. Still with me so far? Oh, and all Vaqueros are essentially large frame fixed sight NMs (we still have not gotten to NEW Vaqueros, be patient grasshopper). I won't go into any details on limited production calibers like .32-20, 10mm, .40 S&W, as those were all large frames.
OK, when the cowboy action shooting scene really, really started to take off, the same troops that had complained about the big NM .357 really started to grumble about the size of the Vaquero, as it was bigger than a (take your hat off sir!) Colt SAA.
So Ruger introduced the New Vaquero, which is a medium frame, and chambered it in .357 and .45 Colt. This was the first time a caliber larger than .357 was available in a medium frame, and it sort of set the wheels to turning with a lot of folks.
Then along came the 50th Anniversary of the Blackhawk in 2005 and Ruger introduced a re-issue of the medium frame, adjustable sighted, flattop .357 Magnum.
Hearts started fluttering everywhere, and lots of boys were scooping up the 50th models and building .44 Specials. Enough were doing so Lipseys was bright enough to see the handwriting on the wall and convinced Ruger to make some runs of the 50th dressed up as a .44 Special. The rest is history.
So now we have NM large frame Blackhawks in all calibers except .44 Special, and New Vaquero medium frames in .357 and .45 Colt, and finally medium frame flattop Blackhawks in .44 Special. Clear as mud? Good, y'all are a Ruger fan now. Take two Bearcats and call me in the morning.
I think I got all that right, but sure as shooting someone will be along shortly to correct my mistakes. I didn't get into flattop vs. non-flattop as that would have taken a few more paragraphs, but that is essentially the jist of things.
