Mowrey, TX, .54 Cal. Allen & Thurber Style Brass Frame Black Powder Rifle

At offer is a hard to come by .54 caliber Mowrey of Olney, Texas, Allen & Thurber Style single shot, Brass frame, black powder muzzle loading rifle. Most of these were made in either .50 or .45 caliber. The rifle retains about 90% original.
The bore appears to be excellent and the stock has a few dings. The hammer spring is broken or missing and needs to be replaced, and the hammer has a bit of wobble. The hammer catches on ½ cock as well as full cock. Due to arthritis, I am unable to disassemble the gun for repair or to offer a better assessment.