Anyone have any suggestions for one?

These are all over the place: http://www.pyramydair.com/customer-d..._Stop_Pin/2401

But they're listed as fitting both 3/8" or 11mm. Since 3/8s is ~9.5mm, that means the picatinny rail will be offset for either 11mm or 3/8s, so I'm hesitant to order one unless someone can tell me for sure that it's the 11mm that's centered.

Thoughts? Suggestions?

O2