Anyone ever seen or heard of one of these?

https://www.ebay.com/itm/Unknown-Gun-Bro...=item1cb8d677c1

"Journal of the Franklin Institute", 1901
https://books.google.com/books?id=acoGAAAAYAAJ&pg=PA93&lpg

The class B or "Counter-Recoil" gun was first patented in 1891 by R. M. Catlin, an American mining engineer. It presents the sole advantage of allowing a longer time between explosion and extraction for the case to cool and contract, facilitating extraction. This is counter-balanced by the fact that the available energy for starting extraction is less than in the class A arm, owing to the slow speed and small energy of movement of the barrel at the start of the counter-recoil when the extraction takes place. This energy of movement and the tension of the recoil spring are the only forces available for extraction. As above stated, the advantage of time for cooling before extraction is of little importance in small arms, and for ordnance, high speed is of such paramount importance that this time cannot be allowed.

The inherent disadvantages of the class are slowness, weak operation, and the necessity of using some form of catch. It is possible this last objection may be eliminated from these guns, but until this is done, the presence of a catch is objectionable. This is principally owing to the practical difficulties of manufacture, tempering, etc., and to the irregular results of rust and dirt on the action of the catch. A spring is also usually necessary to operate it. During a wide experience with guns of this type I have had more difficulty with the catch than with all other parts of the gun together.

No examples of class B have been put on the market, but a number have been constructed. The Catlin-Carr gun has, I believe, been acquired by the Driggs-Seabury Gun and Ammunition Company, and F. M. Garland of New Haven has constructed a number of models of various calibers,—so far with but small success. The rate of fire is only about one half that of similar guns of the previous class.

https://en.wikipedia.org/wiki/Driggs-Seabury

I didn't find anything on the basic google patent internet search, but there is likely one

Good work Drew. I finally thought of pulling Col. Gardner off the shelf and found that Robert Mayo Catlin of Tuscarora, Nevada, had Patent No. 454,993 and Patent No. 574,350 which was assigned to San Francisco Arms Co. Howard Carr of San Francisco, California had Patent Nos. 574,189, 584,153 and 681,439 all assigned to San Francisco Arms Co.