Doublehelix,
here are some #s with SP using the RMR 124gr MPR
S+B SP, very mixed range brass, charges as thrown after setting the measure (Lee auto drum)
using my old high mileage 25K+ rnds 5"9mm 1911
(so it has some wear on the barrel and might be a bit slower, need to test it side by side with my new one when I have a chance---yes I liked the first one so much I bought a spare
since it is most likely going off list in CA
)
String: 3
Date: 8/26/2018
Time: 11:13:30 AM
Grains: 124
Hi Vel: 955
Low Vel: 913
Ave Vel:
933
Ext Spread: 42
Std Dev: 15
3.7 Sport Pistol 124 RMR MPR JHP 1.08
Velocity Power Factor Ft/Lbs
926 114.824 236.072
955 118.42 251.09
934 115.816 240.169
913 113.212 229.491
938 116.312 242.231
String: 4
Date: 8/26/2018
Time: 11:14:49 AM
Grains: 124
Hi Vel: 987
Low Vel: 967
Ave Vel:
981
Ext Spread: 20
Std Dev: 8
3.9 Sport Pistol 124 RMR MPR JHP 1.08
Velocity Power Factor Ft/Lbs
984 122.016 266.571
981 121.644 264.948
986 122.264 267.656
987 122.388 268.199
967 119.908 257.44 This one ruined what would have been a great ES/SD
String: 1
Date: 8/26/2018
Time: 11:17:44 AM
Grains: 124
Hi Vel: 1016
Low Vel: 1001
Ave Vel:
1008
Ext Spread: 15
Std Dev: 6
4.0 Sport Pistol 124 RMR MPR JHP 1.08
Velocity Power Factor Ft/Lbs
1010 125.24 280.845
1001 124.124 275.862
1011 125.364 281.401
1016 125.984 284.191
1002 124.248 276.413
String: 2
Date: 8/26/2018
Time: 11:19:12 AM
Grains: 124
Hi Vel: 1059
Low Vel: 1021
Ave Vel:
1037
Ext Spread: 38
Std Dev: 13
4.2 Sport Pistol 124 RMR MPR JHP 1.08
Velocity Power Factor Ft/Lbs
1059 131.316 308.756
1033 128.092 293.781
1040 128.96 297.776
1036 128.464 295.49
1021 126.604 286.995
I loaded 3.9 and 4 both thinking one or the other might get me to 125 PF, not quite (with any wiggle room)
4.1 would probably do it, but 4.2 gives me a hair more wiggle room.
If I remember correctly in Walkalong's test the S+B SPs were about 15-25 fps slower than CCI SPs so if you are using CCIs 4gr might get you to 125.
(going to miss the S+B SPs, and will need to retest all my loads now that I am switching to CCIs....but still have a couple thousand S+Bs to use up first)