Having recently uncovered an survival shelter sealed in perfect condition, with intended occupant's remains found near the entrance, we have access to more accurate pressure testing, and prediction technologies of the old world.
Taking advantage of this development boon, we have developed the 6x51mm Sioux Scout cartridge based on the following methodology.
Scouts will be shooting primarily at game animals, or ruffians, but occasionally more sturdy animals or targets - therefore a mid-size caliber that we definitely don't have a predisposition for, and certainly haven't found accurate data and a stockpile of reverse engineer-able projectiles for, should be selected. The reason for the use of the smallest and lightest viable bullet is that a harder target like bear, moose, bison, etc may take multiple shots but are likely to be a significantly less frequent ammunition expenditure than marksmanship and skill maintenance training, border patrol, or other police action uses. Given the available scavenged expertly developed projectiles, and development software, we decided to pursue the lightest viable bullets to meet the requirements set forth by the program, which ultimately this lead us to a selection of .224" and .243" 85-105 grain projectiles. We settled on a 95gr secant ogive design of traditional copper jacket lead core construction for both .224" and .243" bullet diameters and noticed that the wider bullet was more powder-efficient, would have a more modest relative capacity and barrel life, and likely be slightly easier to manufacture.
The case we would like to be brass, but for production cost reasons, we concede steel construction but insist on small magnum rifle boxer primers. Sample image is provided in beautiful brass color.
(I am stealing Gripen's characteristics format because it is good and I am lazy)
Cartridge Characteristics:
Bullet Diameter: 0.243
Neck Diameter: 0.267
Shoulder Diameter: 0.3346
Base Diameter: 0.355"
Rim Diameter: 0.355"
Rim Thickness: 0.0591
Case Length: 2.025
Overall Length: 2.750"
Case Capacity: 34.3 grains H2O
Relative Capacity: 2.99 total, 2.62 usable
Recommended Rifling Twist: 1-in-7” (152.4 mm)
Primer Type: Small Rifle Magnum Boxer
Maximum Pressure: 50,000 CUP ( ~ 59,000 psi)
5” Magazine Stack Height: 27 cartridges
Loaded Cartridges
95gr VLD loading:
27.1 gn CuZn5 jacket;
67.9 gn lead core
28.5 gn propellant charge of IMR 4895
75.3 gn mild steel case
3.9 gn small rifle primer
202.7 gn complete round
5.1 cents material cost, complete round
Additional projectiles are currently under salvage operations development.
Mini-Competition: Sioux Scout Rifle Caliber
in Sturgeon's Contests
Posted
!!!Unofficial submission disclaimer!!!
Having recently uncovered an survival shelter sealed in perfect condition, with intended occupant's remains found near the entrance, we have access to more accurate pressure testing, and prediction technologies of the old world.
Taking advantage of this development boon, we have developed the 6x51mm Sioux Scout cartridge based on the following methodology.
Scouts will be shooting primarily at game animals, or ruffians, but occasionally more sturdy animals or targets - therefore a mid-size caliber that we definitely don't have a predisposition for, and certainly haven't found accurate data and a stockpile of reverse engineer-able projectiles for, should be selected. The reason for the use of the smallest and lightest viable bullet is that a harder target like bear, moose, bison, etc may take multiple shots but are likely to be a significantly less frequent ammunition expenditure than marksmanship and skill maintenance training, border patrol, or other police action uses. Given the available
scavengedexpertly developed projectiles, and development software, we decided to pursue the lightest viable bullets to meet the requirements set forth by the program, which ultimately this lead us to a selection of .224" and .243" 85-105 grain projectiles. We settled on a 95gr secant ogive design of traditional copper jacket lead core construction for both .224" and .243" bullet diameters and noticed that the wider bullet was more powder-efficient, would have a more modest relative capacity and barrel life, and likely be slightly easier to manufacture.The case we would like to be brass, but for production cost reasons, we concede steel construction but insist on small magnum rifle boxer primers. Sample image is provided in beautiful brass color.
(I am stealing Gripen's characteristics format because it is good and I am lazy)
Cartridge Characteristics:
Bullet Diameter: 0.243
Neck Diameter: 0.267
Shoulder Diameter: 0.3346
Base Diameter: 0.355"
Rim Diameter: 0.355"
Rim Thickness: 0.0591
Case Length: 2.025
Overall Length: 2.750"
Case Capacity: 34.3 grains H2O
Relative Capacity: 2.99 total, 2.62 usable
Recommended Rifling Twist: 1-in-7” (152.4 mm)
Primer Type: Small Rifle Magnum Boxer
Maximum Pressure: 50,000 CUP ( ~ 59,000 psi)
5” Magazine Stack Height: 27 cartridges
Loaded Cartridges
95gr VLD loading:
27.1 gn CuZn5 jacket;
67.9 gn lead core
28.5 gn propellant charge of IMR 4895
75.3 gn mild steel case
3.9 gn small rifle primer
202.7 gn complete round
5.1 cents material cost, complete round
Additional projectiles are currently under
salvage operationsdevelopment.Representative Performance* (95gn VLD Nominal Loading)
Muzzle Velocity (22” barrel): 2849 ft/s
Muzzle Energy (22” barrel): 1719 ft-lb
Ballistic Coefficient (G7): 0.249
Form Factor (G7): 0.982 - 0.962
Drop at 600 yd: 77.5 in
Drift at 600 yd (90°, 10 mph): 27.7 in
Recoil (10 lb weapon): 4.84 ft-lb
Penetration into pine at 600 yd**: > 15 in
Representative Performance* (95gn VLD Degraded(-200fps) Loading)
Muzzle Velocity (22” barrel): 2649 ft/s
Muzzle Energy (22” barrel): 1486 ft-lb
Drop at 600 yd: 93.1 in
Drift at 600 yd (90°, 10 mph): 31 in
Recoil (10 lb weapon): 4.38 ft-lb
Penetration into pine at 600 yd***: > 14 in
* 2.6 in sight height, 100 yd zero, 59.0 °F, 29.92 in Hg pressure
** when striking at 1795 ft/s or greater
** when striking at 1665 ft/s or greater
Relevant ballistic data
Case head detail
Case Dimensions
Our valuable scavenging find