Introduction: During the last three decades of the 1800s there were at least two hardware stores in the town of Somerset, Pennsylvania that offered gunsmithing services: Holderbaum's and Byers & Barnett. Although we know the names of the hardware stores, we do not know who performed the gun repair services.
1876-1880: As detailed below, John Reboah Megahan married James B. Holderbaum's sister Margaret. Abraham McGahan is identified as a gunsmith on the 1876 tax list of the borough of Somerset. I did not find a listing for Abraham Megahan or his son John Reboah Megahan in the manuscript 1880 census records of the borough of Somerset.
1884: According to a 1906 biography included farther below, James B. Holderbaum began his hardware business in 1884. The following recurring advertisement is from the August 27, 1884 issue of the "Somerset Herald" newspaper, and mentions a gun repair service. Over the following years, Holderbaum advertised heavily in the "Somerset Herald", selling everything from farm equipment to cook stoves.
1885: The following advertisement in the December 2, 1885 issue of the "Somerset Herald" newspaper locates Holderbaum's hardware store at No. 3, Baer's Block. Click here to see a May 12, 1880 ad that puts J.F. Blymyer's hardware store at the same address.
1885: Abraham Megahan was living with his son Milton on East Fourth Street of Williamsport in 1885 and was living in Williamsport in 1897. This seems to mean that Abraham Megahan is not the individual who was performing gunsmithing at Holderbaum's hardware store.
In the following excerpt from the Somerset town map in the 1876 Beers atlas of Somerset County, a red arrow has been added to identify the building that was known as Baer's Block. The building was in the northwest corner of the diamond square, approximately at 40.00860407, -79.07900394.
Based on the second and third story architectural features, I believe the following photo shows the building known as Baer's Block. I believe the exterior features of the first floor have been remodeled, based on a comparison with an old building photo I've seen that depicts more primitive street conditions.
1892: The following recurring advertisement from the October 26, 1892 issue of the "Somerset Herald" newspaper mentions a gun repair service. This advertisement continued to be printed part way into 1893.
1906: The following biography of J.B. Holderbaum is from Volume III of the 1906 book "History of Bedford and Somerset Counties Pennsylvania". The biography mentions that James B. Holderbaum's sister Margaret was the wife of John R. Megalin. The name Megalin is a miss-spelling. Margaret was the wife of John Reboah Megahan, who was the son of the Somerset and Huntingdon County gunsmith Abraham Megahan.