mcb
Member
For fun with the morning's tea...
A hypothetical revolver cylinder. 1.550 inches in diameter and 1.610 inches long. Five 45 Colt chambers cut in it at maximum tolerance per SAAMI specs to make the resulting chamber walls as thin possible. The bolt hole circle was my best guess from looking at pictures, at .950 inches. This resulted in .065 inch walls between chambers and .055 between the chamber and OD. A simplified 45 Colt Case (no primer pocket or flash hole) was placed in one chamber. The cylinder was modeled as carbon steel 4140 quenched and tempered to HRC30. A static Finite Element Model run with 14,000 psi pressure applied to the inside surface of the brass cartridge. The peak resulting von Mises stress is ~67 ksi. The yield strength for this heat treatment of 4140 is ~116 ksi so we are at 58% of its yield strength. Deformation in the above model is plotted at nearly 200 times normal. Maximum deflection at any point in the model was less than .001 inch.
For comparison. I measured my S&W 625 and it has a wall thickness between chambers of ~.072 inch and chamber to OD of ~.070 inch and it will safely shoot 45 ACP +P at 23,000 psi.
I would be happy to update the model with more accurate dimensions or material properties if someone has some info to share. The bolt hole circle dimension from a 44 Special would be awesome. I used 4140 as it is commonly used in firearms but I have no idea what Ruger uses in their blued guns.
A hypothetical revolver cylinder. 1.550 inches in diameter and 1.610 inches long. Five 45 Colt chambers cut in it at maximum tolerance per SAAMI specs to make the resulting chamber walls as thin possible. The bolt hole circle was my best guess from looking at pictures, at .950 inches. This resulted in .065 inch walls between chambers and .055 between the chamber and OD. A simplified 45 Colt Case (no primer pocket or flash hole) was placed in one chamber. The cylinder was modeled as carbon steel 4140 quenched and tempered to HRC30. A static Finite Element Model run with 14,000 psi pressure applied to the inside surface of the brass cartridge. The peak resulting von Mises stress is ~67 ksi. The yield strength for this heat treatment of 4140 is ~116 ksi so we are at 58% of its yield strength. Deformation in the above model is plotted at nearly 200 times normal. Maximum deflection at any point in the model was less than .001 inch.
For comparison. I measured my S&W 625 and it has a wall thickness between chambers of ~.072 inch and chamber to OD of ~.070 inch and it will safely shoot 45 ACP +P at 23,000 psi.
I would be happy to update the model with more accurate dimensions or material properties if someone has some info to share. The bolt hole circle dimension from a 44 Special would be awesome. I used 4140 as it is commonly used in firearms but I have no idea what Ruger uses in their blued guns.