I went to the range today with my new S&W Model 69 with a 4.25" barrel, X-Grips installed, and a complete set of Wolf springs to sweeten the action. All shots today were from the rest position on a bag, at 25 yards, and the barrel and cylinder were given a once through with a brush after every five shots after inspection. There was no signs of leading. The boolit was from a MP 432-256 PB HP 4 mold using the large hollow point pin. The lead alloy used was 94/3/3 with a saeco hardness of 6.2 or about 12BHN if I am correct. The lube used was Bens Red. Boolits were seated to the near top of the crimp groove with a solid crimp. The powder of choice was W296. There was no sticky extraction or oddly damaged primers upon inspection.
I loaded up sets of five starting at 24.0gr and spacing them 0.2 grains apart until I ended up with the maximum load of 25.0gr. Half way through the tests fatigue had set in and groups started to widen slightly but the best load is listed below. The flier in this group was called as I had begun to notice that all groups had a first shot flier to the lower right due to excessive grip in the anticipation of the shot.
24.2gr of W296
245gr SWC-HP
Average Velocity-1296 FPS
Standard Deviation-28 FPS
Group Size- 1 9/16" Four Shots With Called Flier Dropped
The Dirty Girl
Now the standard caveat applies. This was my load that was safe in my gun under these conditions. It may be safe in your firearm or it may not be. Use this info for education purposes and not as a recommendation as to what you should load in your gun.
The next test will be at 50 yards with powders ranging 24.3-24.5 grains of W296 to dial this in once I can get back to the range.