MR09 reproduction flashlight adapter for H&K USP full size

RESTOCK IN SEPTEMBER OF 2025

This is a reproduction clone of Surefire's MR09 flashlight adapter for Heckler & Koch full size USP handguns. This will allow the use of the X300 B model thumbscrew attachment variant (X300U-B, X300V-B, X300T-B) to be adapted to the HK proprietary non 1913 accessory rail found on all USP full size pistols. The adapter is a 2pc design made from 7075 aluminum with a type 3 hardcoat anodizing in black. Hardware is stainless steel socket head cap screws with a thread pitch of 18-8 and a diameter and length of 4/40 x1/2". Recommended torque spec on the bracket is 15 in-lbs. Having a 2pc design allows the X300Ub to sit closer to the trigger guard than a GG&G 3pc 6061 adapter does, and will not sag or flex allowing use of IR laser aiming modules. The MR09 reproduction bracket will fit full size Heckler and Koch USP pistols in all calibers; it will not work on any USP compact frame however. 

Due to variances in polymer frames this bracket may require hand fitting by a certified gunsmith to work on certain HK full size frames in .45ACP calibers. To fit an X300-A model the 1913 picatinny slot bar will need to be installed, and material will need to removed from the back side of the switch where it meets the trigger guard or the light cannot seat and lock into place. A gunsmith certified in HK is recommended to hand fit certain lights and caliber options. The bracket itself can be hand-filed at the screw mating surfaces to remove a few thousandths of an inch off the flats to allow the adapter to tighten up on certain .45 ACP frames.

What are the differences between the GG&G mount and the MR08/09?

The MR08 & MR09 was made by Surefire as a way to adapt the x300B onto the HK non 1913 rail. They were able to place the light as high and tight as possible to the trigger guard for better light activation with either strong or support side hand.  The way they were able to do this is by making the adapter a 2pc design to minimize flex, and by doing do they were able to make the mount ‘fold’ into the rail tightly and precisely. 

GG&G changed the design, and made it slightly worse by making it into 3 pieces; the only driver being cost to manufacture, and then made it out of a cheaper 6061 aluminum. 

The complex angles and tight space at the ‘fold’ makes the MR08 & MR09 only possible to manufacture on a 7 axis mill. It’s a complex and expensive part, but super well designed and executed. 

Back to the GG&G design. 

The 3 pieces allowed it be made on a standard mill. Gone are the complex angles and tight working areas. They attempt to solve this with dowel pins and screws to clamp the 3 parts together, but it does not have have the same strength or rigidity that the MR08 and MR09 have.

The part GG&G works, it’s dirt cheap to make, and does 80% of the job the MR08 & MR09 does. 

The GG&G mount will introduce sagging and loosening up over time. The dowels hog out the hole on its other side mate, the weight of the light at the front of the picatinny diving board, it all creates a sag and loose tolerance that will defeat a laser modules zero. It also makes using kydex holsters that index primarily off the light impossible to be consistent with. 

Last huge difference is placement. The MR08 & MR09 allows activation of the light easily with your finger. The GG&G is just out of reach as their design pushed the light down and away from the trigger guard.