Parker 1904 20 gauge
 

My friend has a Parker 20 gauge manufactured in 1904 according to serial number, Vulcan steel barrels. I can't find any info on Parker 20s. How many were made? What was the usual chambering? Choking? If "Vulcan steel barrels" are equivalent to modern steel, can one safely use modern loads, e.g., 2 3/4" loads?

The chokes and chambers will have to be measured.

In 1904, the "standard" 20-gauge shell in North America was a 2 1/2-inch shell with 3/4- and 7/8-ounce loads driven by 2 to 2 1/4-drams of bulk smokeless powder or the equivalent of dense smokeless powder. With Parker Bros. policy of holding chambers 1/8-inch shorter than the intended shell, 2 3/8-inch chambers in Parker Bros. 20-gauges are pretty common. My 1930 VH-Grade 20-gauge has 2 3/8-inch chambers.

Longer 20-gauge NPEs were offered, but the heavier 2 1/2-drams of bulk smokeless powder or 20-grains of dense smokeless powder, such as Infallible or Ballistite, loads pushing the same 7/8-ounce of shot a bit faster, that was only offered in the 2 3/4-inch or longer shells wasn't a catalog item until later. Those loads are not in 1905 listings but are in 1910, and I don't have any catalogs in between.

What may have been done to the chambers, forcing cones and chokes in the 120 years since the gun in question left Meriden is anyone's guess. Chambers, bores and chokes need to be measured by someone with the proper tools and expertise.

Parker information
 

These may help your friend.

https://www.ebay.com/itm/31531854052...Bk9SR9Dy0vv3Yw

OR

https://www.ebay.com/itm/32611989485...Bk9SR9Dy0vv3Yw