Definitive Guide to SIG Sauer MPX

Many airgun manufacturers are trying to pry their traditional airgun platforms into a modern sporting rifle style with varying degrees of success. What's so great about the Sig Sauer is they actually are a firearms manufacturer first and foremost who wanted to gut their hotly anticipated Sig Sauer MPX centerfire and turn it into a semi-automatic pellet gun. Their motivation was primarily so you could train with their pellet version of the MPX and your training would correlate to the actual firearm. The great thing for everyone else is a very robust gun that instead of pretending to be a tactical style gun, actually is a tactical style gun. And at a fraction of the cost of the firearm.

The Basic Anatomy of the Sig Sauer MPX

The controls are almost all fully ambidextrous. Only the magazine release is right hand only. The safety selector is right above your thumb, and the charging handle above isn't just for show. You'll need to use it after changing CO2 canisters to reset the valve, but not after magazine changes. So while you won't be using it the same way as the actual gun, it certainly looks cool, and it's there if nothing else for training reasons. The weight of the Sig MPX air rifle may surprise those who are used to lightweight, cheaply made tactical style air guns. Remember these guns are made using the same specs as their centerfire counterparts. The housing is full metal construction with the stock, magazine, pistol grip and forearm grip made out of hard polymer. The guns are made to feel like a firearm, and are primarily designed for training purposes, so it's important that their weights are similar. The MPX is powered by one 88g CO2 tank that is screwed into the back of the gun and then hidden inside of the stock. This is one of the only main differences between the centerfire and pellet guns since this does not allow for a folding stock. Note that though the rifles are extremely well made, strong and durable; the weakest point in our opinion was the stock. Commendably, Sig took our feedback on this and strengthened the stock from the initial test versions we had. Including performing drop tests in and outside boxes. We would still be careful about the amount of pressure you place on the polymer stock though. The trigger pull on the MPX does take a bit to get used to. The rifle is essentially double action in that with each pull of the trigger you are both advancing the belt in the magazine as well as opening the valve to fire the pellet. Because of this double action the trigger pull is long and quite heavy, which is to be expected with any CO2 semi-auto repeater. Where the gun differs is in the smoothness of the trigger mechanism, the MPX lacks the grittiness and sloppiness of many CO2 semi-auto air rifles. With some practice you should have no problem firing off some pretty rapid shots. The magazine feed is very well designed patented system call the Roto Belt Mag. The belt easily pulls out of the magazine housing for reloading and then slips back into the mag surprisingly well. As we tested the guns we had no jamming problems and only a few instances of the pellet not being fired when the CO2 got too low. The guns come with a 30rd magazine though Sig plans on releasing a 50rd and 70rd mag as well. We're told extra mags will be available shortly after the initial release. The effective distance of the MPX is up to 25 yards in most environments. Our testing took place on a closed indoor range and we were able to push past that to almost 40 yards with the MPX. Obviously at that distance there was a pretty substantial drop off in accuracy but it was still fun to see what the gun could do. We were able to hold about a 3-inch group shooting offhand at 25 yards. These guns were made to train with and hit your target, not necessarily for punching tiny groups on paper. Velocity is what you would expect out of a CO2 powered gun: ≈ 600 fps in .177 cal & ≈ 400 fps in .22 cal.

Comparing the Sig Sauer pellet MPX to the centerfire MPX

The centerfire MPX was developed by Sig Sauer to replace the classic Heckler and Koch MP5, a 50 year old gun that while timeless, was becoming expensive to service. Sig wanted to develop a replacement weapon system that filled the same role for another 50 years. They also created the pellet version of the MPX to be a training tool. So just how close to these two guns stack up? Since we had access to a centerfire MPX, we ran some comparisons. When comparing between the pellet gun and the centerfire, the similarities are astounding. Truly Sig wants this to be a gun you can use to train and mimic the look, shape, weight, and feel of the actual MPX. It's easy to get the two guns mixed up (in the picture below, the pellet version is at the bottom). Their lengths are nearly identical, with the Centerfire MPX measuring 26.25" and the Pellet MPX coming in at 26". When taking into consideration the weight of a Centerfire MPX fully loaded, it weighs 7.1 lbs. A fully loaded Pellet MPX with 88gr CO2 tank comes in at... weight for it (get it, weight for it...) 7.05 lbs. That's impressive. It can't be stressed enough how well made the pellet version of the Sig Sauer MPX has been made. When you pick it up, it just feels right. There's a heft and density to it that screams quality. And certainly Sig has designed a gun that will turn heads.

Accessories

Up till now there have been very few options in the airgun world to embrace the same level of customization. The MPX air rifle rail systems are the same as its centerfire counterpart. The MPX features the Sig-specific attachment system and comes with two Picatinny side rails for attachments to your heart's content. It comes with a finger stop attached to the bottom Picatinny rail. Along the top of the rifle is 14" of full length Picatinny rail for mounting your favorite optic. The MPX comes with a nice pair of flip-up iron sights, but certainly you may want to add an optic. Sig offers a nice red dot combo. The red dot is exceptional as it features coated optics as well as very tactile rubber power buttons and brightness adjustments. You can mount this without having to remove the iron sights allowing for a more co-witnessed sight picture. Note that the QD sling points do not exist on the pellet MPX. Something we feel Sig could easily correct in the future. Instead you'll want to pick up a Rail Sling Swivel Stud to attach your sling.

Maintenance

Since the Sig rifles are CO2 powered, the valves need a small amount of lubricant. Pick up your favorite brand of airgun oil and add a drop to the tip of the 88gr CO2 cartridges every few cartridges. If you're new to CO2 powered pellet guns, it's important to know that you want to run through as much of the gas in your CO2 cartridge as possible before removing it. Unscrewing the tank with too much gas inside can freeze and potentially damage the valves. When it comes time to replace your 88 gram cartridge make sure to slowly unscrew it from the back of the gun so that any left over gasses can escape slowly without freezing up the valves.