Installing a PVS 22/27 mount on a bolt action rifle: McCann Industries SIRS

McCann Industries SIRS system with PVS22 in place.

 

McCann Industries SIRS system with PVS22 in place.

McCann Industries SIRS system with PVS22 in place.

Installing a PVS 22/27 Universal Night Sight (UNS) mount: McCann Industries Stock Imbedded Rail System (SIRS)

Night vision is becoming increasingly popular among shooters.  Beyond its military, law enforcement and defensive uses, predator and pest control applications have pushed its use into the main stream.  Traditionally, one of the down sides of night vision optics was the inability to use the same sight and zero both day and night.  With the advent of clip on systems like the AN/PVS 22, the day optic, with the same familiar zero, can be used in low light conditions as needed.  This game changer allows the end users familiarity with the day optic system to carry over to low light conditions.

Typically, these night vision systems are mounted to a rail embedded on the front of the rifle stock.  McCann Industries SIRS mount is an excellent proven example of this.

The following documents our installation of the SIRS and is presented for information purposes only.

We ordered the following items from Brownells for this project:

Here are most of the items we will need to install the McCann Industries SIRS mount.  Marine-tex epoxy (top left), release agent (top center), blue painters tape (top right), calibers (middle right), level (bottom right), edge finder (bottom left), SIRS mount (middle left) and 1/4" end mill.

Here are most of the items we will need to install the McCann Industries SIRS mount. Marine-Tex epoxy (top left), release agent (top center), blue painters tape (top right), calipers (middle right), machine setup gauge (bottom right), edge finder (bottom left), SIRS mount (middle left) and 1/4″ end mill.

The mount needs to position the sight approximately 2" in front of the day optic objective lens.  We mount a PVS 22 on the top of the McCann SIRS rail and note the location of the front edge.

The mount needs to position the sight approximately 2″ in front of the day optic objective lens. We mount a PVS 22 on the top piece of the McCann SIRS rail and note the location of the front edge on our SAFE AND EMPTY rifle.

The action is removed from the stock, and the area to be machined for the mount is covered in blue painters tape.

The action is removed from the stock and the area to be machined for the mount is covered in blue painters tape.

A piece of flat stock is placed on the top side of the stock.  A machine set up gauge is used to level the stock front to back with the stock is secured in the vise.

A piece of flat stock is placed on top of the stock. A machine setup gauge is used to level the stock, front to back, while the stock is secured in the vise.

The machine set up gauge is rotated 90 degrees and the stock is checked for level.

The machine setup gauge is rotated 90 degrees and the stock is checked for level, side to side.

We decided to very the the stock was level using a dial indicator.  The indicator was mounted on the mills base.  Moving the stock along the X axis, we were able to very it was level with .001".

We decided to verify the the stock was level using a dial indicator. The indicator was mounted on the mill’s base. Moving the stock along the X axis, we were able to verify that it was level within .001″.

An edge finder is used to locate the front edge and sides of the stock.

An edge finder is used to locate the front edge and sides of the stock.

A 1/4" solid carbide endmill is held in a collet.  The top egde of the stock is located.

A 1/4″ solid carbide endmill is held in a collet. The top edge of the stock is located.

Our end mill was run at the highest RPM and cut smoothly.  The DRO was zeroed at the centerline of the stock and front edge of the the inlet.

Our end mill was run at the highest RPM and cut smoothly. The DRO was zeroed at the centerline of the stock and front edge of the the inlet.

The inlet is .800" deep, 1.660" wide and 2.500" long.  The nut that secured the front sling swivel is too high so we will remove it and reinstall the front stud after the SIRS is installed.

The inlet is .800″ deep, 1.660″ wide and 2.500″ long. The nut that secured the front  sling swivel stud (black disk in the center of the picture) is too high so we will remove it. Once the SIRS is epoxied in place, we will drill and tap the bottom of the mount to accept the sling swivel stud.

The bottom of the SIRS is test fit in the recess.  A few thousandths of play are on each side.  This will be filled with epoxy.

The bottom of the SIRS is test fit in the recess. There should be a few thousandths of an inch of play on each side. This will be filled with epoxy.

The surfaces of the SIRS that shouldn't have epoxy are coated in release agent.

The surfaces of the SIRS that shouldn’t have epoxy are coated in release agent.

The barrel is covered in painters tape.  We select two thick O rings to center the barrel.

The barrel is covered in painters tape. We select two thick O rings to center the barrel.

The top of the SIRS rail is secured with the provided screws.  The assembled mount compresses the O rings, centering the mount on the barrel.

The top of the SIRS rail is secured with the provided screws. The assembled mount compresses the O rings, centering the mount on the barrel.

With the release agent applied, mount centered and assembled on the barre, the barreled action is removed from the stock.

With the release agent applied, mount centered and assembled on the barrel, the barreled action is removed from the stock.

A thin coat of Marine-tex epoxy is applied to the sides and bottom of the SIRS.

A thin coat of Marine-Tex epoxy is applied to the sides and bottom of the SIRS.

The barreled action is lowered into place.  The bottom metal is placed into the stock and front and rear action screws are tightened.

The barreled action is lowered into place. The bottom metal is placed into the stock and the front and rear action screws are tightened.

 

A critical step, a level (in this case our macine setup gauge) is used to level the SIRS so it isn't canted.   We checked to verify the rail installed on the rifle was level, then made sure the SIRS was level.

A critical step: a level (in this case our machine setup gauge) is used to level the SIRS so it isn’t canted. We checked to verify the scope rail installed on the rifle was level, then checked the SIRS.

 

Excess epoxy is removed with clean cotton swabs.  After the majority of excess material is removed, alcohol is used to remove any excess residue.

Excess epoxy is removed with clean cotton swabs. After the majority of the excess material is removed, alcohol is used to remove any residue.  Note: the glossy area on the top of the mount is the release agent.

Once the epoxy has cured, the barreled action is removed from the SIRS mount.  The release agent is removed and any overflow is trimmed back.  The front sling swivel now needs to be reinstalled.

With the action removed, and the epoxy set, the bottom of the stock is leveled in the vise.

With the action removed and the epoxy set, the bottom of the stock is leveled in the vise.

The front sling stud will now be threaded into the SIRS mount.  A #21 drill is aligned in the prexsisting hole and a through hole is drilled.

The front sling stud will now be threaded into the SIRS mount. A #21 drill is aligned in the preexisting hole and a through hole is drilled.

 

A 10 32 taper tap is guided straight in a Tapright tap guide. the 10 32 sling stud can now be installed.

A 10 32 taper tap is guided straight in a Taprite tap guide. The 10 32 sling stud can now be installed.

A new sling stud can now be installed.

A new sling stud is secured into the bottom on the SIRS mount.

McCann Industries SIRS system with PVS22 in place.

McCann Industries SIRS system with PVS22 in place.