Thanks so much for the info. I have proof that he was in the Civil War and in the 19th but mainly wish I could find where he was buried or any info on his death at Chickamauga.

I found Armstrong Stewart's wife's pension records but can not attach the actual image here but it shows: Pvt. Company I, 19th Alabama Regiment

U.S., Confederate Pensions, 1884-1958 about Mary Stewart
Name: Mary Stewart
Application Date: 14 May 1887
Application Place: Cherokee
Spouse: Armstrong Stewart
Pension File Number: 898
Application Type: Widow

Also on the Alabama State Archives it has him listed as well.

Armstrong also had a son named William L. Or could have been W. L. Stewart who was about 18 years old who joined the Confederate side as
well but once he joined, it is like he vanished. No records or anything. Most have him listed as died in the Civil War but I really wish I could find out more.