An unexpected turn of the weather gave me cause to go to the range yesterday .....
Tried BP in my 5-1/2" '71 - 17.5 FFg/160 GCSWC (no gas check installed) lubed with SPG. Shot two groups 'Duelist' at 15 yards after first shooting a group with smokeless - 3.5 Red Dot/160 hard cast SWC. I'm not interested in what my guns can do from a rest, as I will not be shooting them that way.
There was no appreciable difference in group size. All groups were 10 shot groups as feel I get a better indication of the load and my ability than with 5 shot groups. A couple of times I wished I had quit after printing a 4 shot 3/4" cluster with the smokeless load. An occasional 'shooter induced' flyer widened all groups to just over 3".
Oddly, the BP load was closer to POA than the smokeless, which prints 1-1/2" to the right of POA at 15 yds. This became more pronounced at 25 yds with the smokeless load, using a two hand hold, printing 2-1/2" low and 2" right of POA; 6 rds in a nice 2" cluster. Flyers widened that to 4". This was fired right after the BP load. I didn't shoot at 25 yds with the BP load - this time.
As for the 'fun factor', the BP load wins hands down, recoil being at least twice what is with smokeless. A nice, resounding report and lots of smoke. Function was fine with the limited number of rounds fired.
I had not yet printed at 25 yds with the 7-1/2" '71 using smokeless and was gratified with a well centred 10 shot 6"group using a two hand hold.
Then it was time to play, ringing the the 10"x12" 50 yd gong with the smokeless load in the 7-1/2" gun with every shot. I could learn to like these guns ....