83
RIFLE-BARREL STEEL, .30 CALIBER.
No. 7392.
Marks, M 3 C.
Exterior diameter, ".466.
Interior diameter, ".300.
Sectional area, .10 square inch.
Gauged length, 3".
From middle of length of finished barrel. Rolled, and cooled in air.
Applied loads per square inch.	Elongation ׳ per inch.	Successive elongation per inch.	Permanent set.	Successive permanent set.	Remarks.
Pounds.	Inch.	Inch.	Inch.	Inch.	j
1,000	0.	0.	0.	0.	
5,000	. 000100	.000100	0.	0.	
10,000	.000300	.000200			
20,000	.000667	. 000367			
30,000	.001033	.000366			
40,000	. 001367	. 000334			
50,000	.001700	. 000333			
60,000	. 002067	. 000367	0.	0.	
70,000	.002400	.000333			
80,000	. 002800	.000400			
85,000	. 003000	.000200			
89,000	.003133	.000133			Elastic limit.
90,000	.036000	.032867			
91,000	.037167	.001167			
92,000	.038667	.001500			
95,000	.0467	.0080			
100,000	.0600	.0133			
105,000	.0900	.0300			
108,600					Tensile strength.
.pounds.. 108,600 ....do.... 89,000
---inch.. .2033
....do.....003133
----do........136
.. 1"A from neck silky, cup-shaped
17." ,* 30.״ ,14.״ ..
General summary.
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......*.
Reduction in external diameter at point of rupture..
Position of rupture................................
Character of broken surface......................... . ,
Elongation of inch sections............................’