Here is a balistics chart based on 1550fps and approximately hitting where you said at 100 yards. I would suggest you shoot again at 25, 50 and 75 to see if your results match the chart. If its not your velocity is off one way or the other. That or your scope height is different. I hope this helps.

Name: 45 Cal, 300 grn
Ballistic Coeff: 0.180
Bullet Weight: 300
Velocity: 1550
Target Distance: 93
Scope Height: 1.500
Temperature: 70
Altitude: 500
Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity Energy ETA Drop Max Y 10mph Wind Deflect
0 yds -1.50 in 1550 fps 1600 fpe 0.000 sec 0.00 in -1.50 in -0.00 in
25 yds 0.37 in 1467 fps 1434 fpe 0.049 sec 0.46 in -0.48 in 0.18 in
50 yds 1.23 in 1391 fps 1288 fpe 0.102 sec 1.94 in -0.09 in 0.91 in
75 yds 0.95 in 1320 fps 1160 fpe 0.158 sec 4.55 in 0.61 in 2.19 in
100 yds -0.55 in 1254 fps 1047 fpe 0.216 sec 8.38 in 1.66 in 3.89 in
125 yds -3.45 in 1196 fps 952 fpe 0.277 sec 13.61 in 3.13 in 6.17 in
150 yds -7.86 in 1144 fps 872 fpe 0.341 sec 20.35 in 5.06 in 8.95 in
175 yds -13.92 in 1099 fps 805 fpe 0.408 sec 28.75 in 7.49 in 12.20 in
200 yds -21.79 in 1062 fps 751 fpe 0.477 sec 38.95 in 10.48 in 15.91 in