There are no listed RPM's for the 1955-D Washington Quarter, but this coin definitely has something going on with the Mint Mark. With the loupe, it looks like a D/D/D, best I get see/show in the photos is what appears to be D/D. Does it look like an RPM to you, or does it look like machine doubling? I have gone through every device on the reverse (as well as the obverse), and so no other doubling on anything. I would think that if it was MD, the doubling would show in at least one other device. Multiple photos are with the light coming from different angles.
@Beefer518 Do you see all of those parallel striations around the mintmark? That is indicative of die deterioration doubling. Chris
I was pretty sure it wasn't any type of RPM, but just wanted extra eyes on it. I do find it interesting that the doubling is only on the MM though. With die deterioration or machine doubling, I expect to see it in more than one place, but I guess it has to start somewhere. I took another photo from the side of the coin, and now I can see the shelf doubling. Couldn't see this with the loupe.
On a typical MD coin, I can usually pick it out right away. This one had me going though (obviously). From straight above, it really looked like a hardcore D/D/D RPM, but since I couldn't find any reference to one, I had to ask. Yeah, I was impressed as well. I think I'll save this image for future posts like this. I think it will come in handy.