73
RIFLE-BARREL STEEL, .30 CALIBER.
No. 7394.
Marks, M 3 A.
Sectional area, .25 square inch. Gauged length, 1".
From butt of finished barrel.
Rolled, and annealed as usual.
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. .0002	Inch. 0. .0002	Inch. 0.	Inch. 0.	Initial load.
10,000	.0004	.0002			
20,000	.0007	.0003			
30,000	.0010	.0003			
40,000	.0014	.0004			
50,000	. 0017	. 0003			
60,000 68,000	. 0021 .0026	.0004 .0005	0.	0.	Elastic limit.
69,000	. 0050	.0024			
70,000	.00~0	.0020			
71,000	. 0085	.0015			
72,000	.0097	. 0012			
76,000	.0145	.0048			
80,000	.0190	.0045			
84,000	.0240	.0050			
88,000	.03	.006			
92,000	.04	.01			
96,000	.05	.01			
100,000	.06	.01			
107,280					Tensile strength.
					
General summary.
.............................pounds..	107,280
................................do...	68,000
...........................׳...inch..	.18
................................do...	.0026
■fme 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.......................