71
RIFLE-BARREL STEEL, .3C CALIBER.
No. 7401.
Marks, M 3 D.
Sectional area, .25 square inch. Gauged length, 1".
Specimen from the bar.
Applied loads per square inch.	Elongation per inch.	Successive elongation per inch.	Permanent set.	Successive permanent set.	Remarks.
Pounds. 1,000 5,000	Inch. 0. .0001	Inch. 0. .0001	Inch. 0.	Inch. 0.	Initial load.
10, 000	. 0004	.0003			
20,000	.0007	.0003			
30,000	.0010	.0003			
40,000	.0013	.0003			
50,000	.0016	.0003			
60,000 70,000	.0020 . 0023	.0004 .0003	0.	0.	
73,000	.0025	.0002			Elastic limit.
74,000	. 0053	.0028			
75,000	.0068	.0015			
76,000	.0080	. 0012			
78,000	. 0100	.0020			
80,000	.0120	. 0020			
84,000	.0155	. 0035			
88,000	.0190	.0035			
92,000	.0230	.0040			
100,000	.04	.017			
108,000		.01			
116,000	.09	.04			
118,400					Tensile strength.
					
General summary.
.....................pounds.. 118,400
........................do---- 73,000
........................inch.. .18
........................do........0025
granular 80 per.cent, silky 20 per cent
Tensile strength per square inch of original section
Elastic limit per square inch of*original section_
Elongation per inch after rupture.................
Elongation per inch under strain at elastic limit... Character of broken surface.......................