Yeah, you can tell that it was probably higher grade when stamped so it did it's duty! Hope it can be nailed down though. Didn't see it on that big list of popular known counterstamps from a Google search but maybe, hopefully, @BRandM will know something about it
There are a few "Mowry" counterstamps documented, Cascade, but not this one. I'll look around for you later, but have to go to work right now. First impression. Looks to be mid 1870s to 1880s. Bruce
I checked this as much as I could, Cascade, but had no luck. There could be another initial before "C" that we can't see, so makes it even harder to attribute. There is a "D.Mowry" stamp known on an 1851 Large Cent, but there's no picture to compare to the style of yours. It could be a relative, but there's no way to tell. There was also a company called J.S & S.J Mowry Greenville, Ct. in business from about 1850 until 1869 that manufactured axles, springs and other parts for carriages. In 1869 they became Mowry Axle & Machine Co. I couldn't find a record of the partners in that company, so don't know if your stamp has anything to do with them. My estimate for issue date is still c1875 / 1885. I doubt it would be any later. Sorry I couldn't find more for you. Bruce