Hi, RickB,
Sorry, but the DA Frontier Model (1878 Model) was chambered for the .44 Russian, along with .22, .32-20, .38-40, .38 Colt, .41 Colt, .44 German, .44 S&W, .45 Colt and the British .450/.455/.476 (all of which have the same case diameter). The .44 Russian chambering is uncommon, though I don't have an exact number right at the moment.
Hi, S&W 24,
So far as safety is concerned, the gun should be OK to fire, except that .44 Russian ammo may be hard to get. It is being made, but it is scarce. However, those guns have some delicate parts and if anything breaks, a replacement may be difficult and/or quite costly.
You can make .44 Russian brass out of .44 Special or .44 Magnum. If there are no shoulders in the chambers, .44 Special factory loads should work OK. (In spite of the longer case, .44 Special has the same working pressure level as .44 Russian.)
DO NOT ATTEMPT TO FIRE .44 MAGNUM or loads intended for the .44 Magnum in any gun not chambered and marked for that cartridge.
Jim