Sig Sauer P320 M18: A Duty Gun in Civilian Clothes

Sig Sauer’s new P320 M18 is a good fit in any hand, in addition to having the cachet of a military handgun.

Sig Sauer P320 M18: A Duty Gun in Civilian Clothes

As a retailer, you know that many customers want a copy of the guns used by the U.S. Military. There is no denying that a certain segment of buyers wants them. It's primarily because the gun has been adopted by the military, or they believe that the government selects only the best equipment.

And now since the military has replaced the M9 Beretta semi-automatic handgun with the Sig M17 and M18, many customers will want one. So, Sig Sauer recently introduced the P320 M18 to the commercial market.

The military adopted the M17 after rigorous testing against several other handguns. It's a full-size handgun with a 4.7-inch barrel and is based on the Sig P320, which is a polymer-frame, striker-fired 9mm semi-auto. The M18 is the same gun but has a shorter 3.9-inch barrel.

According to Sig, while the M18 has been ordered by all service branches, the Army is the only branch to order the M17. With the slightly shorter barrel, the M18 is just a little better suited for carry, especially in environments where discretion is in order.

Small Differences

The civilian version P320 M18 differs only slightly from the genuine M18, and the differences are so small that only a serious collector would have concern. The civilian gun has different corrosion resistant coatings on the internals and does not have some of the markings called for by contract on the M18. These markings are things like CAGE codes and part numbers. Additionally, the controls on the M18 are finished in flat dark earth while the P320 M18 has black controls.

The M18 also has a slide that is slightly different than the P320 M18. Besides not displaying the model designation of P320 M18, the slide on the military M18 has a single screw under the striker that retains the rear sight plate instead of two screws — one on each side of the striker — on the P320 M18. Actually, it takes less work and less disassembly to remove and replace the rear sight plate on the P320 M18, making it easier for the owner to do without the assistance of an armorer or gunsmith. And the rear sights on the P320 M18 have green tritium vial inserts instead of the orange inserts on the M18. Both versions of the gun have green tritium vial front sights.

The last difference is the recoil spring and barrel fitting. The recoil spring assembly on the military M18 is just slightly stronger than the one on the P320 M18. This is so that the M18 can handle frequent use of +P+ duty loads, and 115-grain truncated cone practice ammunition used by the military. And to accommodate the hotter military loads, barrel fitment has been slightly changed.

An interesting feature on both the M18 and M17 is the ability to change grip size. Several years ago, Sig introduced the P250, which is a hammer-fired polymer-frame pistol that featured a fire control chassis that was the actual serial numbered part. That feature allowed the user to substitute different grip modules for a wide range of hand sizes.

Eventually, Sig made some changes to the P250 design and introduced the P320, which shared many of the same features, including the fire control chassis. But instead of being hammer fired it was striker fired. Then when the U.S. military requested submissions for a new handgun to replace the aging M9, Sig submitted a gun based on the P320.

Sig’s entry won the competition and the U.S. military adopted it as the new sidearm, designating it the M17. Then a slightly smaller version was requested for easier carry by plain-clothes personnel, so Sig reduced the barrel length on the M17. That pistol was approved and given the designation M18. Both the M17 and M18 retain many of the features found on the P320 including the ability to change grip size. It's something that can be quickly done by the owner and does not require a gunsmith or armorer.

Seeing Red

The P320 M18 received for testing had a ROMEO1PRO red-dot sight installed instead of the iron sights that are normally installed on the M18s shipped to the military. Although all testing for this article was done with the red dot in place, SIG did ship the P320 M18 with an iron sight rear plate. And, in case you are wondering, the military M18 is designed for easy attachment of a red-dot sight.

If the owner decides to use iron sights, which are standard on the P320 M18, both front and rear sights are available in different heights to adjust elevation. The front sight is drift-adjustable for windage, but the square-notch rear is not.

Red-dot sights are becoming more popular on handguns these days and an increasing number of law enforcement agencies have authorized personnel to use them on duty guns. Competitors have known the benefits of red dots for much longer, but now even non-sworn civilians who carry are using them. Training and practice are required to use them effectively though, especially if the shooter has been using iron sights for very long.

The ROMEO1PRO is waterproof to a depth of 1 meter and is fog proof. It's also protected by a steel shroud to prevent damage from bumps. Power comes from a single CR1632 coin cell that can be replaced without removing the sight from the slide. While early red-dot sights proved to be short lived when installed on the reciprocating slide of a semi-automatic handgun, current red-dots are much more robust and durable.

The ROMEO1PRO has a 3-MOA red dot but is available with a 6-MOA dot. It was a solid performer and held zero all through testing. The dot has 10 daylight brightness levels and two nightvision settings. Battery life is rated at 20,000 hours. That's a lot considering there are only 8,760 hours in a year.

The power can be turned off or left on without draining the battery, because the sight is equipped with Sig’s motion activated illumination system, or MOTAC. If the unit detects no movement after a short period, it powers down, but immediately powers up the instant the unit is moved. The red dot can be adjusted for zero by turning adjustment screws, one for elevation and one for windage. One MOA increments are marked to make it easy.

Easy Control

Because it eliminated the difficulty most people have with focus when using iron sights, groups at 25 yards were probably better than they would have been with iron sights.

The gun performed flawlessly during the entire test period with no malfunctions regardless of the ammunition tested, which included Sig's Elite 115-grain FMJ, other brands of ball ammo, Black Hills Honey Badger 125-grain loads, Sig's 115-grain V-Crown JHP self-defense ammunition and Hornady's 124-grain XTP JHP ammo.

Although the P320 can be had with or without an external thumb safety, the P320 M18 comes with one. That's because the military M18 has one. The safety can be operated from the right or left side of the gun and is positioned for easy control. The manual says the gun can be carried with a round in the chamber and the safety disengaged because the gun is equipped with a striker and a disconnector safety.

Although the magazine catch is located on the left side of the gun, it can easily be switched to the right side. The P320 M18 comes with one 17-round magazine with a flat baseplate and two 21-round magazines with extended baseplates. Besides the takedown lever, magazine catch and trigger, the only other control is the slide stop, which is also ambidextrous. It is large enough to be easily manipulated, but not too large to be activated accidentally.

If the grip doesn't feel right in your customer's hand, it’s easy to correct the fit. The grip modules are available online, but a smart retailer will have one of each size on hand for the customer to try.

Many disliked the Beretta made M9, which was the official U.S. Military handgun for many years. But many of those same people will like the Sig, and even those who don't may still want one for their collection.


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