Could someone have put a .50 BMG sight blade onto a 1917 sight base...? That seems to be the logical conclusion. Of course,if the WC .50 BMG had the same sight base as the 1917...then this could be an original. Only person I know who has a .50 WC sight is member Mouse. He might be able to answer the question.
I, too, know the seller. Have for years, and he is a good guy. What is important to know is that only two components in this assembly are different than the 1917A1 sight assembly. Most, as pointed out above, are interchangeable. First, the leaf itself, which differs only in the graduations, this being the proper 3200 yard leaf for the M2 Water Cooled .50. Dimensionally, the leaf is otherwise identical. The combination slide parts are identical and share all the same drawing numbers with the .30 cal. The movable base and windage screw assembly are also the exact same parts for both .30 and .50 cal. So, the only other different component is the fixed base that is screwed to the top plate of the M2 with the same 3-hole pattern as the air cooled .50 base.
Now I can see that both bases have Colt markings, though these can also be found with no markings and with High Standard markings, as I have had examples of both. I can't see any marking on the sight itself, but have seen these with both H.S. and Colt markings, as I recall. Now there were three makers of the water cooled .50: Colt's, High Standard and Frigidaire. Have yet to see marked F sight parts, so theirs might be the unmarked, but I can't say for certain. I do see some Colt marked windage screws, and a couple of the combo slide parts with Colt marks as well. These were most likely made for the .50, but could easily get mixed with .30 cal components, being identical.
A forum community dedicated to Browning 1919 A4 firearm owners and enthusiasts. Come join the discussion about performance, gunsmithing, restoration, troubleshooting, reviews, accessories, classifieds, and more!