Originally Posted by
Outpost75
.455 Pressure Test Data - Submitted by Larry Gibson, Lake Havasu, AZ
Test Firearm – T/C Contender .45 Colt 10” with strain gage interface to Oehler M43 Ballistic Test System
All test loads assembled in Starline .45 Schofield brass shortened to 0.87” length and rims turned,
Winchester LP primer, weighed charges of 3.5 grains Alliant Bullseye throughout.
Accurate 45-240H (252 grs., 10 BHN) .452”, OAL 1.29” – 639 fps, 11,400 psi max.*
• Only one shot recorded a high enough pressure to measure on the strain gage
Accurate 45-260H (269 grs., 10 BHN) .452”, OAL 1.30” – 648 fps, 14 Sd, ES 42, 11,800 psi, ES 900 psi
Accurate 45-290H (295 grs., 10 BHN) .452”, OAL 1.298” – 672 fps, 11 Sd, 32 ES, 12,600 psi, ES 1100 psi
Expected velocity drop in 6” barrel revolver estimated -100 to 150 fps, depending upon cylinder gap.
.455 Revolver Vs. Rook Rifle Velocity Test Data
_____________________________Velocity (fps), Sd _________Kirst Conversion______”Rook Rifle”
_____________________________Webley Mk VI 6” Bbl.______Ruger ROA 7-1/2”______H&R 20”
_____________________________Cylinder gap 0.018”_______Cylinder gap 0.004”_____Solid Bbl.
Kynoch K42 Mk VIz 265-grain FMJ___537 fps, 29 Sd___________580 fps, 32 Sd________680 fps, 40 Sd
Handloads Assembled in Hornady .455 Mk II cases (0.77”) with Winchester LP primers
#452374 225-gr. LRN 5.0 Unique____648 fps, 24 Sd____________716 fps, 11 Sd_______814 fps, 14 Sd
MiHec 265-gr. Mk I 4.5 Unique______538 fps, 24 Sd___________679 fps, 32 Sd________788 fps, 11 Sd
Accurate 45-259H 3.5 Bullseye______622 fps, 6 Sd____________720 fps. 16 Sd________813 fps, 18 Sd
Handload in Starline .45 Schofield Case modified to .455 Mk I (0.87”)
Accurate 45-259H 3.5 Bullseye______546 fps, 16 Sd__________641 fps, 9 Sd_________753 fps, 11 Sd
Column Means By Gun_________Webley 0.018” cyl.gap_____Ruger 0.004” cyl. gap_____20-inch rifle, solid barrel
Pooled Avg. All Samples:___________578 fps________________667 fps______________770 fps
Velocity Gain from Webley__________0____________________+89 fps______________+192 fps