Col. William Brophy, Arsenal of Freedom - The Springfield Armory, 1890-1948
Krag-Jorgensen Model 1894 .30-40
C < .5%
Mn < .6%
S < .034%
P < .045%
AISI 1044

Roy Dunlap Gunsmithing, 1963
https://books.google.com/books?id=7Ab12fHr8y0C&pg=PA181&lpg
Army “Ordnance Steel”
C - .45 - .55%
Mn - 1.00 - 1.3%
P < .05%
S < .05%
AISI 1551
Tensile strength 110,000 psi; yield strength 75,000 psi
“I believe the Savage Arms Corp. uses this (steel) for all center-fire rifles.”