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Proof Mark – Muzzle Stand-off Device for the Glock 19 & 23

Tuesday, June 12th, 2018

Proof Mark LLC is a veteran owned firearm accessories design and manufacturing company located in the Pacific Northwest. They recently released their Muzzle Stand-off Device (MSD) for the G19/23. Project development began in October of 2015 and concluded in Spring of 2018.


The design intent originates in part with the Battle of Qala-i-Jangi where an SFOD-A, after expending their ammunition, had to defend their position using their empty weapons in hand-to-hand combat.  Another source of inspiration was a special mission group in Slovakia, where there were several reports of Glock slides coming out of battery due to muzzle contact.  The MSD has utility in kinetic operations and as well as CCW. FBI statistics show more than half of law enforcement firefights take place at distances of 0 to 5 feet.  When in close contact with an assailant the MSD prevents the slide from being pushing out of battery.

The MSD body is machined from billet 7075 aluminum and the glass break is 17-4 stainless.


The locking mechanism consists of a Patent Pending 303 stainless locking block which fits within the profile of the STANAG 4694 rail and allows for tool-less removal.


The MSD went through extensive testing which revealed two primary design obstacles; gas management at the muzzle and frame fitment.  First, capturing excess gas behind the stand-off device generates a tremendous amount of force on the pistol dust cover and this can lead to material fatigue.  This challenge was overcome with the use of proper venting.  Second, inconsistencies of Glock dust covers between generations and even within a single generation made universal fitment difficult.  To overcome this obstacle, balance was struck between critical dimensions to achieve a good fit on Gen3/4/5.

With solutions engineered and production eminent, Glock released their new Gen5.  This extended the development cycle as the slides of the Gen5/19X are longer than prior generations which caused interference with the back of the MSD.  This was overcome by recontouring the back of the MSD.

Prior to public release, the MSD went through a year of testing within one of the military’s special mission groups with positive feedback.

The MSD G19/23 fits the Safariland 7TS G17/22 XC1 holster.  Look for the following first eight digits: 7378-8322-XXX.  The last three digits indicate right/left hand configuration.



Variants of the MSD for the G17/22 and G34/35 are forthcoming.

The company website is:

Instagram: @proof_mark