87
RIFLE BARRELS, .30 CALIBER.
The finished barrels from which these sections were taken for hydrostatic tests by interior pressures in the powder chambers were forwarded from. Spring-field Armory.
Tensile tests of the material next precede these results.
No. 10290.
Section marked M3 A,
Annealed as usual.
Pressure per square inch.	Barrel section.		Remarks.
	Diameter.	Expansion.	
Pounds.	Inches.	Inch.	
16,300	0.980+	0.	
24,450	.980+	0.	
28,520	.982	.002-	
32,600	.986	.006-	
34, 640	.988	.008-	
36,670	.990	.010-	
38,710	.991 +	.011	
40,750	.994-	.014-	
16,300	.993	.013-	
42,790	.997	.017-	
44,820	.999	.019-	
48,900	1.005	.025	
52,970	1.013	.033	
57,050	1.032	.052	
61,120	1.057	.077	•;i
16,300	1.056	.076 •	
			
No. 10291.
Section marked M 3 A.
Annealed as usual.
Pressure per square inch.	Barrel section.		Remarks.
	Diameter.	Expansion.	
Pounds.	Inch.	Inch.	
16,300	0.980	0.	
24,450	.980+	0.	
28,520	.980+	0.	
32,600	.981	.001	
34,640	.981	.001	
36,670	.981	.001	
38,710	.981	.001	
40,750	.981	.001	
16,300	.980	0.	
42,790	.981	.001	
44,820	.981	.001	
46,860	.981	.001	
48,900	.981+	.001+	
50,940	.982+	.002+	
52,970	.984+	.004+	
55,010	.989	.009	
57,050	.991	.011	
61,120	.996+	.016+	
16,300	.995+	.015+