aterry33
Member
In particular, I'm curious how their 180grain load does in a 4" K Frame.
SAMMI lowered the 357 mag pressure from 46,000 CUP down to 35,000 CUP.. The factory loaded 357 mag is DEAD no matter who puts them together...
That is correct. When you examine the S&W ammo brochures from the year before the 1978 testing change, and the year after, you see that their 158 grain .357 round dropped from a claimed velocity of 1500 fps using "industry standard test equipment" (a quote from that brochure) to 1146 fps from a 6" Model 66 (the numbers stated in the next brochure). The drop in velocities I believe was mainly driven by the change to realistic testing methods. If in the early 1970's you thought your .357 sidearm was producing 1500 or 1450 fps with factory 158 grain ammo, you were being mislead by the industry.when you realistically adjust the older velocities figures from the 8 or 10" solid chamber test barrels used at the time to 4" vented test barrels that simulate actual 4" revolver velocities more accurately.