Winchester says that the BC = 0.109 when fired at an MV of 1085 FPS.
You can put that into some program like JBM Ballistics and get a close approximation for your rifle, with its sight height above the bore. But you are going to have to shoot any load in your rifle in 10 yard increments beyond 50 yards in order to know the actual drop and holdover or turret clicks to aim at longer ranges.
And there are programs which will let you enter the actual drops at various ranges and compute the actual BC for you, if you also measure the MV. To my way of thinking, it is just easier to shoot the various ammunition and make some notes of how many clicks, or what the BDC mark actually corresponds to in yards.
Here are some old BCs of 40-gr match ammunition...As you can see, it lists the Winchester at 0.150, and some Eley at .150 and others at 0.105 for the same weight and MV. That is why you can't use the first "data" you find.
RWS, 40-gr. R100 (213 4195), 1175 MV, 123 ME, 0.130 BC
REMINGTON, 40-gr. LR Target Solid (6122) (6100), 1150 MV, 117 ME, 0.149 BC
WINCHESTER, 40-gr. T22 LR Std. Vel. Solid (XT22LR), 1150 MV, 117 ME, 0.149 BC
FEDERAL, 40-gr. LR Ultramatch Solid (UM1), 1140 MV, 115 ME, 0.149 BC
FEDERAL, 40-gr. LR Match Solid (900), 1140 MV, 115 ME, 0.149 BC
AGUILA, 40-gr. LR Std. Vel., 1135 MV, 114 ME, 0.158 BC
PMC, 40-gr. Scoremaster LR Std. Vel. Solid (22SM), 1135 MV, 114 ME, 0.111 BC
FIOCCHI, 40-gr. LR Biathlon Match Solid (22SM340), 1120 MV, 111 ME, 0.140 BC=Estimated
AGUILA, 40-gr. LR Match Golden Eagle, 1100 MV, 110 ME, 0.109 BC
LAPUA, 40-gr. LR Polar Biathlon Solid (4317023), 1100 MV, 107 ME, 0.108 BC
ELEY, 40-gr. Tenex Ultimate EPS, 1085 MV, 105 ME, 0.150 BC
ELEY, 40-gr. Match EPS, 1085 MV, 105 ME, 0.150 BC
ELEY, 40-gr. Club, 1085 MV, 105 ME, 0.150 BC
ELEY, 40-gr. Target, 1085 MV, 105 ME, 0.105 BC
ELEY, 40-gr. Practice, 1085 MV, 105 ME, 0.150 BC
ELEY, 40-gr. Standard, 1085 MV, 105 ME, 0.150 BC
ELEY, 40-gr. Biathlon Match, 1085 MV, 105 ME, 0.150 BC
ELEY, 40-gr. LR Silhouex, 1085 MV, 105 ME, 0.150 BC
REMINGTON/ELEY,40-gr. Match EPS (RE22EPS), 1085 MV, 105 ME, 0.149 BC
REMINGTON/ELEY, 40-gr. Club Extra (RE22CX), 1085 MV, 105 ME, 0.149 BC
REMINGTON/ELEY, 40-gr. Target Rifle (RE22T), 1085 MV, 105 ME, 0.149 BC
AGUILA, 40-gr. Match Rifle, 1080 MV, 100 ME, 0.197 BC
SELLIER and BELLOT, 40-gr. LR SB Standard (SBA02201), 1084 MV, 104 ME, 0.131 BC
SELLIER and BELLOT, 40-gr. LR SB Standard (SBA02202), 1084 MV, 104 ME, 0.131 BC
FEDERAL, 40-gr. LR Ultramatch Solid (UM1B), 1080 MV, 105 ME, 0.139 BC
FEDERAL, 40-gr. LR Target Solid (711B), 1080 MV, 105 ME, 0.138 BC
FEDERAL, 40-gr. LR Match Solid (900B), 1080 MV, 105 ME, 0.139 BC
RWS, 40-gr. LR Target Rifle (213 2478), 1080 MV, 100 ME, 0.109 BC
CCI, 40-gr. LR Std. Vel. Solid (0032), 1070 MV, 100 ME, 0.105 BC
CCI, 40-gr. LR Green Tag Comp. Solid (0033), 1070 MV, 100 ME, 0.105 BC
CCI, 40-gr. LR Pistol Match Solid (0051), 1070 MV, 100 ME, 0.105 BC
RWS, 40-gr. LR R50 (21304187), 1070 MV, 100 ME, 0.105 BC
LAPUA, 40-gr. LR Master Solid (4317033), 1066 MV, 101 ME, 0.132 BC
LAPUA, 40-gr. LR Midas L Solid (4317022), 1066 MV, 101 ME, 0.132 BC
LAPUA, 40-gr. LR Midas M Solid (4317021), 1066 MV, 101 ME, 0.132 BC
NORMA 1, 40-gr. Lead, Round Nose (15613), 1066 MV, 101 ME, 0.132 BC
NORMA 2, 40-gr. Lead, Round Nose (15614), 1066 MV, 101 ME, 0.132 BC
NORMA 3, 40-gr. Lead, Round Nose (15615), 1066 MV, 101 ME, 0.132 BC
FIOCCHI, 40-gr. LR-Rifle Match Solid (22SM320), 1050 MV, 98 ME, 0.140 BC
FIOCCHI, 40-gr. LR Match Trng. Solid (22M320), 1050 MV, 98 ME, 0.130 BC
LAPUA, 40-gr. LR Super Club Solid (4317066), 1050 MV, 98 ME, 0.114 BC
LAPUA, 40-gr. LR Std. Rifle Club Solid (43122420), 1050 MV, 98 ME, 0.114 BC
PMC, 40-gr. Match Rifle (22MR), 1050 MV, 98 ME, 0.110 BC
RWS, 40-gr. LR Rifle Match (213 4225), 1035 MV, 95 ME, 0.096 BC
ELEY, 40-gr. Tenex Ultimate EPS Pistol, 1030 MV, 94 ME, 0.109 BC
ELEY, 40-gr. Pistol Xtra, 1030 MV, 94 ME, 0.109 BC
ELEY, 40-gr. Target Pistol, 1030 MV, 94 ME, 0.109 BC
LAPUA, 40-gr. LR Pistol King Solid (4317031), 1033 MV, 95 ME, 0.130 BC
LAPUA, 40-gr. LR Pistol Trainer Solid (4312260), 1033 MV, 95 ME, 0.130 BC
ELEY, 40-gr. Pistol Match, 1000 MV, 89 ME, 0.140 BC
FIOCCHI, 40-gr. LR Pistol Match Solid (22SM300), 984 MV, 86 ME, 0.130 BC
FIOCCHI, 40-gr. LR Match Trng. Solid (22M300), 984 MV, 86 ME, 0.125 BC
PMC, 40-gr. Match Pistol (22MP), 900 MV, 72 ME, 0.095 BC
WINCHESTER, 40-gr. LR Lead HP (W22LRB), 1150 MV, 117 ME, 0.150 BC
ELEY, 40-gr. LR Subsonic Xtra Plus, 1065 MV, 100 ME, 0.115 BC
RWS, 40-gr. LR Subsonic HP (213 2494), 1000 MV, 90 ME, 0.092 BC
LAPUA, 40-gr. LR Multi Match Solid (4317020), 1100 MV, 129 ME, 0.134 BC