No Alan, the Ruger .44 mags are just the opposite!
When Elmer Keith and Harold Crofts put together the SAAMI specs for the .44 Magnum, they specified a throat dimension of .432" diameter and a bullet diameter of .432"! As late as 1980, Norma of Sweden was still making their .44 mag bullets .432" as well as Remington their half-jacketed lead SWC factory ammo utilized .432" up through 1979 at least.
In an effort to lower pressures and liability, the big ammo and bullet makers manufacured their .44 caliber bullets at .429" and .430". Lower pressures it did, but it also raised hob with accuracy. Consequently, Smith & Wesson was the first to reduce throat dimensions on the chambers in their revolvers to .430", which resored the accuracy of these fine guns.
If you will remember in the mid 70's through the early 80's, Dan Wesson was the king of accuracy on the Silhouettas Metalicas circuit. Their revolvers have throats that measure .428"-.429", and are superbly accurate with today's jacketed and commercially cast bulelts.
Now about Ruger! They are the last of the revolver manufacurers to still hold fast to the original SAAMI specs for the .44 Magnum. The majority of their revolver cylinder throats measure .4315"-.432", just as the originators of the cartridge called for! Put a .4315"-.432" hard cast gas checked bullet in these guns and they shoot like they were designed to! No problem having to open up undersized throats here! Actually the Ruger throat dimensions make for almost perfect dimensional relationships with throat and barrel diameter for cast bullet shooting!
The .45LC guns that Ruger is producing today however are a horse of a different color that have throats measuring .450-.451" and must be opened up to .452"-.453" to shoot well with anything! Generally Ruger will tell customers that the guns are "within specification" and not open up those throats!
Hope this answers a question or two for you!
God Bless,
Marshall