Looks to like a T/C, 12" barrel, in .357, with 158 grain Buffalo Bore, ought give on order of 1800 fps. For a 158 grain JHC bullet traveling 18800 fps, the ballistics look something like:
Range Velocity Impact Drop ToF Energy Drift
0 1800 -0.5 0 0 1137 0
10 1747 0.14 0.09 0.02 1071 0.47
20 1703 0.68 0.29 0.04 1018 0.6
30 1659 1.09 0.61 0.05 966 0.8
40 1616 1.37 1.06 0.07 916 1.08
50 1573 1.51 1.65 0.09 868 1.45
60 1532 1.53 2.37 0.11 823 1.9
70 1493 1.39 3.24 0.13 782 2.44
80 1454 1.09 4.27 0.15 742 3.07
90 1416 0.64 5.46 0.17 703 3.79
100 1380 0 6.83 0.19 668 4.6
1137 ft-lbs out the barrel, 668 ft-lbs at 100 yards, does not strike me as light weight. I'd think this very viable to bring down a deer out past 100 yards.
3. 5 inch S&W model 27
a. Item 19A/20-180gr. Hard Cast =1398 fps
b. Item 19B/20-170gr. JHC = 1380 fps
c. Item 19C/20-158gr. Speer Uni Core = 1457 fps
d. Item 19D/20-125gr. Speer Uni Core = 1543 fps
4. 6 inch Ruger GP 100
a. Item 19D/20-125gr. Speer Uni Core = 1707 fps
5. 18.5 inch Marlin 1894
a. Item 19A/20-180gr. Hard Cast = 1851 fps
b. Item 19B/20-170gr. JHC = 1860 fps
c. Item 19C/20-158gr. Speer Uni Core = 2153 fps---- Can you believe this?!!!
d. Item 19D/20-125gr. Speer Uni Core = 2298 fps---- Or this?!!!
http://www.buffalobore.com/ammunition/default.htm#357