Based on discussions with a ten times PPC Champ, his standard load was 2.7 grains Bullseye with a 148 LWC. He claimed, in a K frame revolver, I think it was a Shilen barrel, with 600,000 rounds through the tube, that he still got two inch groups at 50 yards. That is darn impressive.
Depending on your lot of Bullseye, you may have to adjust it up a grain, lot to lot variation is real.
4" S&W M10-5
148 LWC
2.7grs Bullseye W/W cases WSP
19-Apr-09 T ≈ 60-65 ° F
Ave Vel = 696.2
Std Dev = 12.04
ES = 48
High = 721.3
Low = 673.3
N = 32
v accurate, about 2" low, no leading, mild recoil
4" M66-2
148gr LBBWC
2.7 grs Bullseye CCI 500 primers
17-Oct-93 T = 65-70°F
Ave Vel =704fps
Std Dev =18
ES =57
High =742
Low =685
N =6
Colt Police Positive Special 4" Barrel mfgr 1930
Zero 148gr LWC Factory
4 Sept 2005 T = 72 °F
Ave Vel = 810
Std Dev = 72
ES = 213
High = 943
Low = 730
N = 6
Colt Python Stainless Steel, 6" Barrel
148 gr LBBWC
2.7 grs Bullseye 38 SPL cases CCI500
24 Sept 1999 T = 78 ° F
Ave Vel =710
Std Dev =18
ES =72.02
High =746.1
Low =674
N =32
shot fine at 25 yards, no leading, light recoil
Colt Cobra 2" barrel
148 gr LWC
2.7 grs Bullseye thrown, Fed 100 primers mixed cases
30-Jan-05 T = 42 °F
Average 606
SD 18.19
ES 56.64
High = 633.1
Low = 576.5
32 recorded shots
Accurate shoots 6" high and a little left
S&W M638-3 Airweight Bodyguard
148 LWC Valiant
2.7 grs Bullseye thrown Mixed Brass WSP
18-Mar-07 T = 52 °F
Ave Vel = 611.6
Std Dev = 22.04
ES = 75.92
High = 648.1
Low = 572.2
N = 25
little high