I'll give you a for instance of what the longer barrel does using Lil'gun anyway, I get a 400fps increase over Hodgdon's 7¼" barreled handgun data, in a 20" barreled 45 Colt H&R BC Carbine that will shoot 250gr jacketed bullets at over 1900fps using Ruger/TC load data for Lil'gun, did a little experimenting using the Hornady 250gr SST muzzleloading bullet using the same data from Hodgdon for the 250gr XTP, accuracy is good at 100yds, here's the potential ballistics using Sierra Infinity software. They aren't cheap at $10-$12 for 20, but would make a nice 150yd deer round out of the 45Colt in a bit longer handgun barrel I would think if the trajectory is close to the prediction, 3" high at 100yds puts it dead on at 150yds and 3" low at 175yds. I get the same velocity with the 250gr Speer GDHP using the same data.
Tim
Trajectory for Custom .451 dia. (45 cal) 250 gr. SST at 1900 Feet per Second At an Elevation Angle of: 0 degrees
Ballistic Coefficients of: 0.21 0.21 0.21 0.21 0.21
Velocity Boundaries (Feet per Second) of: 720 720 720 720
Wind Direction is: 0.0 o'clock and a Wind Velocity of: 0.0 Miles per hour
Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 0.0 Vertical: 0.0
Altitude: 0 Feet with a Standard Atmospheric Model.
Temperature: 59 F
Data Printed in English Units
Range Velocity Energy Momentum Drop Bullet Path Wind Drift Time of Flight
(Yards) (Ft/Sec) (Ft/Lbs) (Lb-Sec) (inches) (inches) (inches) (Seconds)
0 1900.0 2003.6 2.11 0.0 -1.5 0.0 0.000000000
25 1813.0 1824.3 2.01 -0.31 0.64 0.0 0.040410915
50 1728.8 1658.9 1.92 -1.28 2.12 0.0 0.082775723
75 1647.7 1506.9 1.83 -2.98 2.88 0.0 0.127215091
100 1569.9 1367.9 1.74 -5.48 2.83 0.0 0.173850143
125 1495.7 1241.6 1.66 -8.86 1.9 0.0 0.222799891
150 1425.3 1127.5 1.58 -13.21 0.0 0.0 0.274174654175 1359.1 1025.3 1.51 -18.64 -2.97 0.0 0.328070501
200 1297.5 934.4 1.44 -25.24 -7.12 0.0 0.384560653
225 1241.0 854.7 1.38 -33.13 -12.55 0.0 0.443683287
250 1189.8 785.7 1.32 -42.43 -19.4 0.0 0.505428702
Trajectory for Speer .451 dia. 250 gr. GDHP (45 Colt) at 1900 Feet per Second At an Elevation Angle of: 0 degrees
Ballistic Coefficients of: 0.165 0.165 0.165 0.165 0.165
Velocity Boundaries (Feet per Second) of: 800 800 800 800
Wind Direction is: 0.0 o'clock and a Wind Velocity of: 0.0 Miles per hour
Wind Components are (Miles per Hour): DownRange: 0.0 Cross Range: 0.0 Vertical: 0.0
Altitude: 0 Feet with a Standard Atmospheric Model.
Temperature: 59 F
Data Printed in English Units
Range Velocity Energy Momentum Drop Bullet Path Wind Drift Time of Flight
(Yards) (Ft/Sec) (Ft/Lbs) (Lb-Sec) (inches) (inches) (inches) (Seconds)
0 1900.0 2003.6 2.11 0.0 -1.5 0.0 0.000000000
25 1789.8 1777.8 1.99 -0.31 0.77 0.0 0.040673404
50 1684.2 1574.3 1.87 -1.31 2.36 0.0 0.083875493
75 1583.8 1392.3 1.76 -3.06 3.19 0.0 0.129801991
100 1489.1 1230.7 1.65 -5.69 3.15 0.0 0.178646924
125 1400.7 1089.0 1.55 -9.3 2.13 0.0 0.230589297
150 1319.4 966.1 1.46 -14.01 0.0 0.0 0.285776436175 1245.9 861.5 1.38 -19.97 -3.38 0.0 0.344299458
200 1181.1 774.2 1.31 -27.33 -8.16 0.0 0.406160863