"J.S.A." were the initials of Joseph Sumner Adams, Springfield Armory-Foreman.

(I have been searching online 'Vital Records' (marriages and births) for Maine and Massachusetts, as well as Census records, to verify the actual full name).

Significant findings that verify full name:

1. 1860 U. S. Census (Saco, York County, Maine):
Joseph S. Adams - male, age 22, est. birth 1838. (Son of John & Elizabeth Adams, both age 58).

2.Maine Marriage Record (Saco, York County, Me.):
Marriage - 29 Sept, 1862 - Jos. Sumner Adams & Sarah P. Rumery.

3. 1865 Mass. State Census (Springfield, Hampden Co., Mass.):
J. S. Adams, age 27, machinist & Wife - Sarah P. Adams.

4. 1930 U. S. Census (Springfield, Hampden Co., Mass.):
Adams, Joseph S. - age 92 & Wife - Sarah P. - age 80 (note - actually should read 87 years old). "Ages at marriage" given as 24 and 19 years old, respectively. (The couple was still living at #99 Bay St., where they had been, since at least, 1900). Their home was valued at $4,500. (Joseph and Sarah were both listed as being born in Maine).

Further observations: Joseph Sumner Adams and Sarah P. Rumery had 5 children of whom 3 daughters survived to adulthood. Their only son, John S. Adams, born July 13, 1863, at Springfield, is listed in the 1865 Mass. State Census, but, not the 1870 U. S. Census. In the 'Vital Records' of their children, Joseph Sumner Adams is listed as being from Saco, Maine. Sarah P. Rumery is listed as being from Calais, Maine.

J. Sumner Adams seems to have preferred using "J. Sumner Adams" in records. He was still working at the Armory at least until 1910. They owned their own home and had an Irish Maid in 1900 and also in 1910 Census.

"J.S.A." and Mrs. J.S.A. had long lives and a long marriage. "J.S.A" had a long career at Springfield Armory. He must have been quite talented and well paid. As 'Foreman', he must have supervised and overseen much of the tooling and manufacture of both Krag and early 1903 Springfield rifles.