Holosun 407/507K mounting standard is based on the Shield RMS/SMS mounting standard. It is often referred to as its modification. There are two main differences:
The two rear sockets are missing on the Holosun 407/507K mounting standard.
The two sockets in the front part of the mounting surface are shallower on the Holosun 407/507K mounting standard.
Holosun 407/507 footprint
Because there are not many dedicated Holosun 407/507K adapters on the market, it is not uncommon for 407/507K owners to purchase a Shield RMS/SMS adapter and modify it so that it can be paired with Holosun 407/507K red dot sights. The pins at the rear must be removed or filed down, and the pins in the front must be shortened in height. These procedures are best done by a gunsmith.
There are two screw holes between the rear and the middle section of the mounting surface. The screws are put into place from above, through the housing of the red dot sight.
Only a few optic-ready pistols are designed to be used in combination with a red dot sight that has the Holosun 407/507K mounting standard. Compact optic-ready pistols are often designed to be paired with a red dot sight that has the Shield RMS/SMS mounting standard. In such cases, modifications must be made to the pistol (or the plate) in order to mount a red dot sight with the Holosun 407/507K mounting standard on it.
Holosun 407K/507K mounting standard
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