M17 Reboot Part 2

M17 Reboot Part 2

Un-boxing and mounting the Sig Sauer Reflex Sight

By Dennis Adler

As none of you have this yet, we are going to share this airgun experience step-by-step. So think of this installment on the M17 Reboot as a still frame video. With the new M17/M18 Low Profile Reflex Sight in hand (the mention of the M18 unfortunately does not hint at a forthcoming M18 CO2 model but rather that this sight comes with a mounting base for the M18 Air Soft model as well), I am going to un-box and follow the directions to install the Sig reflex sight on an M17 ASP.

It’s a box full of little wonders from Sig Air. Included are the Low Profile Reflex Sight with dust cover (shown on the sight), two mounting plates, tools, instruction manual and a lens cloth. The only extra tool needed is a small Phillips head screwdriver.

What comes in the box?

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Everything is neatly held in a foam rubber container form fit for the sight with dust cover attached, a screw driver to use for adjusting windage and elevation, a windage and elevation gauge, the hex head wrench for locking the seating screws, two mounting plates M17/M18, the battery, lens cloth and instructions. It is the instructions that are the most interesting because they appear to have been written by someone who is already familiar with the steps and it leaves out some minor details that would be helpful when a question arises. I fumbled through and will go step-by-step to circumvent the absent info which would have been useful.

Parts by the numbers, 1 are the two sets of screws provided for mounting the reflex sight to the mounting base, (it comes with an extra set), 2 a screw driver made for adjusting windage and elevation on the Sig Air red dot, 3 and 4 the respective mounting bases for the air pistol or Air Soft Sig models, 5 the wrench for the seating screws, 6 the Sig Air Low Profile Reflex Sight, 7 a windage and elevation gauge, and 8 the dust cover for the sight.

The product description in the small instruction manual is very concise and all parts of the reflex sight are easy to identify. The explanation of operating features, (which we will get into in Part 3), is also well written and leaves nothing to added. It is the instillation steps that lead to some minor confusion, but nothing that a little observation of what came off where and how it goes back can’t sort out. The only real issue I had was fitting the mounting plate to the bottom of the sight. The pins and holes (there are four) didn’t quite line up, or so it seemed at first. What I found was that I had to lightly deburr the front two pins to fit into the corresponding holes, and then retouch the finish with some aluminum black. With the battery inserted as instructed, it was hand in glove from there on; the base clicked into place and easily secured with the two hex head locking screws provided (there is an extra set included, too).

The battery (1) is inserted into the base of the sight and is held in place by the mounting plate when it is attached. The plate has four pins (2 red arrows front and rear) which correspond to holes in the bottom of the sight (red arrows). The seating screws (3) have a layer of blue lock tight like material around the threads. The holes in the mounting plate (4) face the rear and allow the screws inside the slide to pass through into the pistol’s white dot rear sight, which is used to lock the plate assembly to the slide.
I had to deburr the two front posts on the mounting base in order for it to fit into the corresponding holes in the bottom of the reflex sight. Once done, the base and sight snapped together easily. At this point, you flip it over and use the seating screws provided to secure the sight to the mounting plate.
Sig Air provides the correct size hex head tool for locking the mounting plate and sight together. Since the mounting plate also becomes the bottom of the reflex sight, it will have to be removed whenever the battery requires changing. Sig says it should last quite awhile since replacing the battery is a total reversal of the mounting procedure.
The sight is now ready to be mounted to the slide, but first you have some work to do.

Once the base and sight are paired up, you move to the slide. Following the instructions for field stripping the M17, remove the magazine, pull the slide back to align the disassembly notch with the takedown lever, rotate it down, pull the slide the rest of the way to the rear, lift it up and then forward over the frame and barrel to remove. Now it gets interesting.

Start with field stripping the M17 and removing the slide from the frame, which is a relatively easy procedure done by clearing the gun, removing the magazine, pulling the slide back to align with the disassembly notch, rotating the takedown lever, then pulling the slide all the way to the rear and lifting it up and forward over the frame and barrel.

There are four steps to mounting the optics plate to the slide the first being to remove the slide from the frame. Then turn the slide over and remove the rear sight screws. That’s the pair we told you not to remove in previous articles. These are Phillips head and you will need a proper fitting screwdriver for this step. The screws are long and have locking washers at the base and you need to completely remove them from the slide.

Turn the slide over and look at the back. There are two screws (first red arrow) that have to be completely removed. What the instruction manual does not tell you, is that when you do this the white dot rear sight and rear slide cover (second red arrow) also come off.
Here is a closer look. The slide cover is part of the same piece that the screws into the slide. The screws pass through in order to anchor the mounting plate by threading into the rear sight posts. I originally thought the rear sight was part of the mounting plate but that is not the case, it is a separate piece.

What the book doesn’t mention is that when you remove the screws, the rear sight also comes off from the base plate (because that is what anchors the screws) and the entire rear slide cover plate comes off as well. It is built as one piece with the screw base. You end up with two screws and locking washers, the rear sight and rear slide cover as individual parts to reinstall later. From this point on it gets pretty easy. None of this is explained in the assembly instructions.

This is what you end up with after removing the two screws which pass completely through the slide; the rear sight and the slide’s rear cover (red arrow) and screws. After that, you can lift the standard mounting plate up from the back and take it off the milled section of the slide. This is “basically” the same design as the centerfire M17 models but parts (mounting bases) are not interchangeable between the 9mm and CO2 slides.

The next step is to lift up the entire mounting plate on top of the slide and remove it. Save this in the open slot left by the M17 air pistol optics base. Take the reflex sight and base assembly and place it on top of the slide by inserting the forward tab into the opening in the front and then setting the entire unit into the slide channel.

It is time to head into the final step by mounting the reflex sight to the slide. Begin by slipping the front tab on the mount (red arrow) into the notch in the slide and then lower the mounting base into the milled channel…
Put the white dot sight (still sitting on the manual) back into the holes at the back of the mounting plate (that’s why it has such long posts), and then tighten down the rear screws inside the slide.
Here you can see the final assembly (with the original mounting plate sitting on the manual), the rear cover for the slide and rear sight reinstalled, and everything screwed down. All you have to do is put the slide back on the frame and you end up with this…

Put the rear white dot sight back in place (inserted into the holes in the new mounting plate) and holding it all together, flip it over. Put the slide cover and screw base back in place, then use the original screws and locking washers to tighten the mounting plate and reflex sight to the slide. Put the slide back on the frame and you have an impressively new looking M17 ASP with a flush mount red dot reflex sight.

…a much improved Sig Sauer P320/M17 ASP pistol ready for some serious range time. To be continued.

In Part 3 it’s time to sight in and see what an optic’s equipped M17 ASP can do.

[Note: As soon as the Sig Sauer sight is on the Pyramyd Air website I will add a direct link to this article]

2 thoughts on “M17 Reboot Part 2”

  1. “Sig Air provides the correct size hex head tool for locking the mounting plate and sight together. Since the mounting plate also becomes the bottom of the reflex sight, it will have to be removed whenever the battery requires changing. Sig says it should last quite awhile since replacing the battery is a total reversal of the mounting procedure.”

    The LaserMax Spartan sights also require disassembly in order to remove / change the battery. What are the odds of the lithium battery leaking corrosive material while installed? I prefer to remove the batteries when the reflex sight is not in use to protect against battery leakage.

    I received an email that these airgun reflex sights are already in-stock and available at Sig Air if anyone doesn’t want to wait for Pyramyd Air to get them.

    • Charles,

      As it turns out, after initial installation, you can remove the sight from the base to change the battery without taking the entire mounting plate assembly off the slide, another thing not noted in the manual. As for battery life, it is estimated at 10,000 hours on the lowest setting. The Sig optic should be available through PA shortly.


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