M17 Reboot Part 3

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M17 Reboot Part 3

Down to business with the Sig Sauer Reflex Sight

By Dennis Adler

The Sig Sauer P320/M17 ASP was not a tack driver during any of its previous range tests, but it was good enough for its intended purpose as a fixed sight military handgun for close quarter to medium range use. Yes, the 9mm M17/M18 models are far more accurate than the 4.5mm CO2 model which is intended as a training gun and for general sport shooting. The M17 ASP is a darn good gun as designed and can keep groups tight at 10 meters, but it’s no target pistol. But can it be, now that the airgun is equipped with a dedicated Sig Sauer design Low Profile Reflex Sight mounted to the slide?

It’s a whole new gun when you add the Sig Sauer Low Profile Reflex Sight to the M17 ASP. It goes from a combat pistol to something closer to a target pistol.

Simple operation

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Like most reflex sights the Sig is simple to activate, this design with one button on the front of the housing. Some reflex sights have a separate On/Off button or switch and + and – buttons to adjust brightness, the Sig does it all with one. To turn it on press the button momentarily, press again momentarily to increase brightness settings (there are 6 levels), and hold for 2-seconds to turn off, (or cycle though the brightness setting and it will turn off after the highest setting). With the gun drawn it is easiest to reach the button with the support hand index finger and adjust the red dot brightness to the necessary level. I prefer a switch on the side of the housing or even the back, but this front position works well enough and you can leave it on the entire time for a short shooting session.

The meld of the seating plate and sight into the slide keeps the lines of the M17 clean and the optic as low to the bore axis as possible. The large rubber covered button on the front of the housing is used for On/Off and brightness functions.

The battery life is 10,000 hours (depending upon the brightness level, but another source says 4000 hours, suffice to say it lasts through a lot of shooting either way), and the unit  automatically shouts down after 1 hour (I shot that long and it did). If you end up exhausting the battery, Sig says you do not have to remove the entire sight and mounting plate from the gun (pairing them up was just part of the initial installation), you just remove the two locking screws in the sight that secure it to the base, and lift the sight off; replace the battery and reattach. This also means if you want to go back to the fixed sights all you need to do is removed the optic, not the entire base. This too, is not mentioned in the manual. That said, it is advisable to remove the battery for prolonged storage, although I have yet (and this is after more than a year or more in some optics, lights and lasers) to have a battery leak or corrode, but these are in guns that are supposed to be ready to use at any time. For the air pistol, if it is going to be put on the shelf for more than a few months, best to play safe and remove the battery. Be sure to put the cover on the sight and store it in the foam liner.

When you need to replace the battery, which has a very long life on the lowest brightness setting (at least 4,000 hours), you do not need to remove the entire assembly from the slide, just the two hex head locking screws and then lift the sight off the mounting plate.

Sighting in

I’m not looking for velocity right now just accuracy, so I am deferring to my favorite 4.5mm pellets, RWS Meisterkugeln Professional Line 7.0 gr. lead wadcutters for sighting in. While heavier and slower downrange than the best H&N Sport Match Green alloy wadcutters, I know pretty much how this gun (which I had for over a year) works with Meisterkugeln.

I’m starting with the reflex sight as it came from Sig Sauer and I have no idea if there is a factory default setting or not, but to begin I am shooting from 21 feet using a Weaver stance and two-handed hold (on the indoor range because it is raining). Sighting on the center target dot, my first three rounds hit low by 2.5 inches and right by 1.5 and 2.0 inches. I adjusted elevation up by 2 clicks and windage left by 2 clicks. This was insufficient so I adjusted another 2 clicks each. This corrected my windage but elevation was still 1.5 inches low so I went big and raised elevation by four clicks; still not enough, 4 more. That was too much, so down 2 clicks. And that’s the ticket. I got the gun sighted in from 21 feet with Meisterkugeln in only 16 shots.

Windage and elevation are easy to adjust with the included screwdriver. There are two locking screws at the back of the sight (blocked by the white dot rear sight) that have to be loosened slightly when making windage and elevation adjustments, but they were already loose enough on the test sample. The soft click adjustments stay put, so even if you don’t tighten them, the locking screws it is not a problem when sighting in for a specific pellet and distance. Since the locking screws are blocked by the white dot sight it appears you would have to remove the sight to tighten them. I’m going to ask Sig Air if this is correct.

Using a Birchwood-Casey Shoot-N-C silhouette and firing from 21 feet at 1-second intervals, I put 9 out of 10 rounds into 1.0 inches, plus a flyer low left in the 10 ring at 8 o’clock for a 10-round group of 1.875 inches, and a best 5-round group clustered over the X at 0.62 inches.

Windage and elevation are easy to adjust with the included screwdriver. There are two locking screws at the back of the sight (blocked by the white dot rear sight) that have to be loosened slightly when making windage and elevation adjustments, but they were already loose enough on the test sample. The soft click adjustments stay put, so even if you don’t tighten them, the locking screws it is not a problem when sighting in for a specific pellet and distance. Since the locking screws are blocked by the white dot sight it appears you would have to remove the sight to tighten them. I’m going to ask Sig Air if this is correct.

I finished off the 20-round magazine with another 10 shooting at a 10 meter target from 21 feet. With the red dot covering the bullseye, 10 and most of the 9 ring, I put 7-rounds into less than a dime-sized hole in the 7 and 8 rings at 12 o’clock, and the remaining three in the 9 and bullseye (actually just cutting the edges, not dead on, but it counts). The 7-shot group measured only 0.53 inches, and the total 10 rounds 0.93 inches. It was high but tighter than I have ever done with the M17 ASP using the open sights.

My best of the day was seven of 10 rounds in a less than dime-sized hole, a little high, but tight. The other three hit in the 9-ring and bull. I could not be more satisfied with this roughly $50 reflex sight mounted on the M17 ASP.

We’ll wrap up in part 4 with a 10-meter test using an IPSC competition silhouette target and the Meisterkugeln 7.0 gr. lead wadcutters.

3 thoughts on “M17 Reboot Part 3”

  1. Seems to show what the pistol is capable of. My feeling has always been that co2pistols are as accurate as 22 rimfire at the limits of co2 power, but are limited by their sights, most being crude and not adjustable.

    • True in most cases, especially with semi-autos. Now, Colt Peacemakers, that’s another thing because a 7-1/2 inch pellet model will outshoot all but a few semi-auto pellet and top drawer CO2 BB pistols. Right now at 10 meters I would put the optics mounted M17 ASP up against a comparably sized .22 LR fired off hand at the same distance for accuracy (of course, not velocity or FPE). As a CO2 powered semi-auto target trainer, the M17ASP has definitely moved up the ladder with the Sig optics.

  2. I’m very pleased to see your review of the M17 with the dot sight; very useful; many thanks.

    A question about your group on the 10 meter air pistol target at 21 feet: You say:
    ” I put 7-rounds into less than a dime-sized hole in the 7 and 8 rings at 12 o’clock, and the remaining three in the 9 and bullseye “.
    Did you shift your aim point after you saw the first 7 rounds went high?

    Guy Carden

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