My dad has an H&R single shot that he bought at Bob & Mickey's in Mercersburg, Pa. back in the late eighties.
They were taking them, cutting about a foot off the barrel and resleeving them with a fixed, tight choke. Spray paint camo job and a sling.
Those things were ridiculous....turkeys didn't have a chance, lol.
Too bad you don't live closer (he lives in South Central Pa.), I think he may be looking to sell it. I think he has a case of Federal 4s also.