Hi folks,
I thought this might be of interest. I just got back from chronographing four different Double Tap loads (one five-shot string of each) through my S&W 1076 (4.25" bbl, std rifling). The range was about fifty degrees Fahrenheit, and at about 5300 feet above sea level. Here's what I got.
180-gr Gold Dot JHP: average 1291 fps, extreme spread - 38 fps, standard deviation - 15.32 fps
180-gr FMJ match: average 1198 fps, ES - 50.30, SD - 21.02
200-gr XTP JHP: average 1141 fps, ES 21.24 fps, SD 9.21 fps
200-gr FMJ-FP: average 1220 fps, ES 63.47, SD 25.31
The 180-gr Gold Dot load kicked noticeably more than the other loads, and threw the brass hell-and-gone the furthest (despite the extra-power Wolff recoil spring and firing pin spring I've installed per Mike's advice). I was quite impressed with its performance, though, and will darn sure keep carrying it as my walking-around-civilization load. I was surprised to see how mellow the 200-gr XTP load developed from the short 1076 barrel. I had been carrying that as my hiking load, but now I'm giving some thought to just going with the warmer 200-gr FMJ-FP load.
Incidentally, I'd been getting noticeable primer swipes, but installing the extra-power firing pin spring that came with the heavy-duty Wolff spring has almost eliminated this.
I hope this was of some interest.
cheers, erich