I second amvet's request and thank dfarris for his info - once more. I used all of the first-go-round Mk III's in the 70's and didn't buy into them; Lawman and Trooper Mk III. I thought they were very clumsy guns compared to the Python I was using at the time and the Brand X #19 that I liked, too. (I never got excited about the Brand X #28 and #27 for this same reason, but the action was not clumsy - just heavy guns.) I did have a friend that could out-shoot me and my Python with his 6" Trooper Mk III, easily! I found the trigger reach to be too far and the hammer throw very long and the stocks just a tad too big for my hand at the time. (Now, I don't mind it at all!) Sights were nice and I liked the wide, smooth trigger and compromise hammer spur - not service, not target. Just right in-between; big enough for fast SA and small enough to stay out of the way in fast 2X shooting. From recent talk on these pages, I gather the Mk V's are not easy to find but I'd liked to know more about them, too. I do think all of the breed are really strong, accurate guns but not as slick as the Python.
A major difference that was over looked was the size of the grip frame.
The MKV is way smaller than the MKIII. The stocks used on the 2" Lawman MKV were only used on that particular gun with that particular barrel length.
This was due to the MKV 2" grip frame being different in size and shape from the 2" MKIII and different from the Lawman MKV & MKIII in the 4" versions. Try to find a set of original stocks for a 2" MKV!
The MKV gun was only produced for 2 years. Huge difference compared to the 14 year run of the MKIII.