81
RIFLE-BAEREL STEEL, .30 CALIBEB.
is o. 7390.
Marks, MSB.
Exterior diameter, ".166.
Interior diameter, ".300.
Sectional area, .10 square inch.
Gauged length, 3".
From middle of length of finished barrel. Rolled, and annealed at residual heat.
Applied loads per square inch.	Elongation per inch.	Successive elongation per inch.	Permaneni set.	Successive permanent set,	Remarks.
Pounds.	Inch.	Inch.	Inch.	Inch.	
1,000	0.	0.	0.	0.	
5,000	. 000100	. 000100	0.	0.	
10,000	.000300	.000200			
20,000	. 000633	. 000333			
30,000	.001000	. 000367			
40, 000	. 001333	. 000333			
50,000	. 001700	.000367			
60,000	.002033	.000333	0. .	0.	
70,000	. 002367	.000334			
80,000	.002700	. 000333•			
90,000	. 003033	.000333			
91,000	. 003067	.000034			Elastic limit.
92,000	.013333	.010266			
93,000	. 021000	. 007667			
94,000	. 022333	.001333			
96,000	.023833	.001500			
100,000	. 029333	.005500			
105, 000	. 038333	.009000			
110,000	.0500	.0117			
115,000	.0700	.0200			
120,000	.1133	.0433			
121,200						Tensile strength.
-pounds.. 121,200
....do... 91,000
---inch.. .1633
....do... .003067
....do...	.096
.. ". 75 from neck silky, cup-shaped .. ".10, 'M3, ".26*
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.................7777.......
H. Doc. 508----6