OPF-G, RMR happens to work with Holosun 407C X2 and 507C variants. 508T is a rather loose fit on OPF-G, RMR, the plate design that's meant to hold the sight immobile isn't able to keep 508T from excessively moving along the bore before the sight to plate screws are installed, we do not recommend 508T on any of our RMR plates. As of late 2023, we've seen samples of late production 508T that's tighter on our plates, newer 508Ts might now work properly with OPF-G, RMR.
Holosun uses a rather curious combination of 90 degrees metric countersink holes on their sights, while keeping the inch pattern thread pitch on their screws (in order to work with Glock pattern MOS plates). RMR and SRO countersink holes are 82 degrees, 6-32 x 3/8.
The 6-32 x 3/8, 82 degrees countersink angle screws we provide with OPF-G, RMR, OPF-P320, RMR, OPF-S, RMR, OPF-DPP, RMR should not be used with Holosun sights due to the difference in countersink angles and length of the screws.
If you do use Holosun 407C and 507C series sights with our RMR plates, you must use the short set of screws that come with your sight, not the long set, nor the screws we provide with our plate.
As a policy, we only support sights made in the US, or allied countries. Dimensional differences and inconsistency (we're not going to make separate plates for each model and sub versions within each model) are one of the reasons, the other reasons are irrelevant in this article. If you know us, you probably already know them.
Our plates are machined in 4140 ordnance grade steel, but it's not immune to user induced misuse and abuse. This can happen when the wrong screws are used, and the user kept torqueing the screws till the plate is bent.
Below are additional pictures from our friend Bunny_Operator https://www.facebook.com/bunnyoperator