I've owned (own) all three revolvers mentioned. The S&W J frame (Model 34) is the smallest and is all blue/steel. The HiStd 109 (Sentinel?) is next in size and is aluminum framed. The H&R 999 is the largest and heaviest (all steel). This revolver was at one time considered a target revolver. By far the best of the three is the S&W J frame, models 34,35,63, etc. than the H&R 999. Hope this helps.