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This is a guest post written by my buddy, CASES4CASES:

It had been on my list to pick up another air rifle. So when the SIG MCX Semi-automatic air rifle in .177 caliber became available for pre-order at a discounted price I put down the cash, crossed it off the list, and stuck it in the back of my mind due to the estimated several months wait. Well, today I was surprised by the arrival of the air rifle – nearly a month early. Apparently it caught SIG off-guard, as well. . .

After a fruitless search of their site for extra magazines — I had only the one it shipped with — and any other air gun accouterments, I called them for assistance. The gentleman I spoke with was quite surprised that I had received the rifle already and expressed that he believed customers were not supposed to receive them until next month. Regardless, extra mags and other accessories are not currently available, which is annoying but not unbearable, given it’s an air gun. SIG does plan to add a new area to their website to host all air gun-related items.

Fortunately, the correct CO2 cartridges are easy to find and the MCX does come with a mag, so out came the box cutter, off went the shipping box, and I was left with a very fancy, shiny, graphics-heavy air rifle box.


While the design on the outside of the box does a great job of conveying that this is not a real firearm, but more of a “dangerous toy,” the inside is an impressive display of tight-fitting Styrofoam that fully protects the rifle. Is this over-engineered packaging a result of the product being made in Japan? Maybe. And if so, I’m okay with that. Heck, it’s nicer than the packaging for most “real” rifles.


Picking up the air rifle, my initial reaction was, “Wow! This thing has some weight! My AR-15s don’t weigh this much, do they?…I hope.” The MCX comes in at around 8 pounds with the CO2 cylinder, which is heavy for air rifles, but decent for tactical training.

The rifle feels good when shouldered. Due to the ergonomics and balance it feels a bit like a SCAR to me, which I find strange. However, it is very comfortable and easy to manipulate.

The aluminum upper and lower receivers are combined, then split vertically into a left receiver and a right receiver, then re-assembled. The finish of the aluminum feels nice and the weight helps with balance of the rifle. The combination of metals and plastics throughout the MCX is just about right.


However, one thing that already bothers me is the faux-ambi setup. The selector and charging handle are ambidextrous but the magazine release is right-handed with a fake button on the left side. This reduces its effectiveness as a good training rifle and especially if you run a truly ambidextrous AR.


All of the controls (selector, mag release, charging handle, trigger) are sloppy. They have lots of play in them. They rattle. I think SIG could have done a better job here. The selector has a good, resounding feedback click. The charging handle has a particularly short throw — another aspect that diminishes the air rifle’s ability as a training rifle. The two-stage trigger gets the job done, but is has a lot of take-up and creep and is, frankly, just plain loose and wobbly. Okay…honestly, the trigger sucks. It’s probably the second worst part of the rifle. I do like that SIG incorporated an over-sized trigger guard, but with the sloppy trigger I’d prefer a straight trigger guard that is closer to the bottom of the trigger. The forward assist, shell deflector, takedown pins, and dust cover are all part of the mold and are not functional.


The magazine well is a bit rough and houses four ribs (two on each side) that correspond with groves on the magazine. To my surprise, the magazine inserts quite well and locks audibly and with little slop. However, the magazine won’t drop free. I have to yank on it to get it out and the rib/groove alignment seems to be the point of lock-up. I’m hoping another magazine might perform better.


Speaking of the magazine; I’m going to cut to the chase. It’s the worst part of this air rifle system. I was drawn to it initially because of the 30-round, semi-automatic pellet capability. I was skeptical of the rotary-style system within the magazine. Holding one in my hands confirmed my suspicions. The magazine feels like a very cheap McDonald’s toy…from the 50’s. I guarantee this is the first part that fails in the rifle.


To load the magazine, the 30-round internal belt is removed and pellets are inserted into the belt. The air rifle comes with a pellet seating tool that helps to ensure the pellets are correctly and securely within the belt. I like the tool, but it’s one more thing to keep track of.


Once loaded, the belt must be inserted back into the magazine in a very specific way, and is only to be moved in a clockwise direction. Moving the belt in a counter-clockwise direction can cause, “serious damage to the magazine.” The frustrating part of this directive is that there is no distinction of what position the magazine needs to be in when determining clockwise and counter-clockwise. Essentially I have a 50/50 chance of causing “serious damage” to my magazine, right out of the box. And I think it’s fair to say that loading a magazine is no quick matter.


Forward of the receiver and cloaked in a suit of keymod attachment holes sits the polymer handguard. It’s basic, secured well, and feels good. I appreciate that it is not over-engineered. A basic fore-grip sits on the bottom of the handguard and can be moved or removed as desired.


The faux suppressor very prominently extends about 7.5” past the handguard and has some mass to it. It also has those “pokey things” on the end cap, if you’re into that. SIG decided to use a different finish on the can, but not the cap, which has a similar finish to the receiver. I think it would look a bit more cohesive if all the metal parts had the same or very similar finishes, especially since the vast majority of the plastic components match nicely.


A 1913 rail extends down the full length of the handguard and receiver. The forward half is plastic; the aft half aluminum. I’m not confident that the fore and aft sections line up. If that’s the case, the included iron sights may end up being throw-a-ways.

Flip-up iron sights come installed on the rifle and are fairly decent. They are made of both plastic and metal parts and are relatively heavy, with a small and large aperture. Included is a front and rear sight adjustment tool.


The pistol grip is narrow and mostly smooth with two patches of texture on the palm swells. SIG made a good decision when they designed this air rifle to accept most aftermarket AR platform grips. I believe that the one included is sufficient and I won’t be swapping it out for another.


At the rear of the receiver begins the stock/CO2 cartridge housing. Depress a button on the side of the stock near the receiver and the entire stock slides backwards and off the air rifle. Simply screw in a 90 gram (or 88 gram, depending on which part of the manual you’re reading) CO2 cylinder into the back of the receiver, slide the stock back over the cylinder and into the locked position and you’re in business. The stock is minimalist and lacks some basic features. The stock is fixed — no adjustments allowed. And there are two faux QD holes. A QD will fit into them nicely, but they lack the locking recesses so they pop right out. Why not make them functional? One feature I do enjoy is the rubber butt pad. It’s a nice touch and is thin, given that the air rifle has negligible recoil.

The overall weight distribution and balance in this air rifle is excellent. This was achieved by the placement of the faux suppressor at the front, the aluminum receiver in the middle, and finally the 90 gram CO2 cylinder at the end.

I had a few minutes to put some shots down range with this air rifle. It performed adequately and responded well. The shots are very audible and there is a nice, small recoil bump. The faux suppressor creates quite a large shot signature in the form of expelled condensation that appears white. Accuracy rating TBD, but 5-shot groups at 20 yards with the iron sights, shooting from unsupported standing position look something like this.


The SIG MCX air rifle has the SIG stamp on it so my expectations were automatically above-average. However, I have to keep reminding myself this is only an air rifle. A $200 air rifle, at that. And for the money, I think it’s a great plinking or even training air rifle.

I look forward to more time on the range with the MCX air rifle. Expect a full shooting review of some of SIG’s new air guns and accessories by Jeremy S. in the coming months.


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  1. “The gentleman I spoke with was quite surprised that I had received the rifle already and expressed that he believed customers were not supposed to receive them until next month.”

    This…makes me extremely leery of Sig even more. This indicates a missmatch of dates and communications stopgaps at at least one point in the leadership chain.

    Combined with Sig-Exeter’s less than stellar reputation regarding rifle QC recently (the 556R, removal of the old long stroke legacy 556 series, the abortive 556 in general, the 556xi failing youtuber MAC twice, etc.) and the debacle of the MPX’s engineering-vs-marketing caliber-conversions, it makes me wonder if the chain of command for each department at Sig is just completely running in the dark respective to each other (which leads to the mistakes and loss of brand reputation).

    Don’t get me wrong; I love Sig’s designs, and I wish I had all of them.
    I just wish I could trust them to not break my heart.

    • Functionally, I’d agree.
      However, there is that whole tax stamp cost/being on another government list thing that sways my mental calculus…

      • There are definitely lots of cost considerations (gun, ammo, tax stamps, the suppressor itself, etc) plus legal limitations. If memory serves, where CASES4CASES lives he’s legally okay playing with a pellet gun on his property but it’s against the law to discharge a firearm.

        BTW in response to some of the other comments, SIG poached the CEO of GAMO to create and run SIG’s airgun division. I haven’t received my T&E rifle or pistol yet so have no opinion, but hopefully the quality is there right off the bat. Apparently in addition to SIG air guns, there will also be SIG air gun ammunition, targets, and some other related stuff. It seems like the goal is both to sell fun, quality air guns as well as sell air guns that mimic the real things in terms of controls and weight pretty dang closely.

        I heard through the grapevine that Cabela’s and Amazon each placed like $7MM to $9MM initial stocking orders from the SIG air gun catalog. So if you’re thinking “this is silly; why would SIG do it,” there’s obviously market demand.

        • That’s correct, Jeremy. I cannot discharge a firearm (not even by new Horton Storm RDX crossbow!) on my property. Air guns are about it for me when I’m outside at home.

        • “…there’s obviously market demand.”

          Well, there’s retailer demand, anyway. Whether there’s sustainable customer demand remains to be seen.

  2. In my opinion, this cheapens the SIG Sauer brand. Is this air rifle comparable to other high end brands?

    I don’t see how this fits into the whole business model of branching out into suppressors and optics. Whereas those products have a high end ‘feel’ to them, this air rifle looks like cheap plastic.

    • HK and just about every other major manufacturer has an AIR Rifle version of every gun in their product lines. Does this make HK look cheap to you?

      • That depends on whether HK’s offerings are quality, well-made airguns, or cheap plastic toys like this SIG appears to be. That magazine, in particular, looks like a fragile mess that will likely be a pain in the ass to load.

        It’s a little odd that SIG wants to make premium, high-quality firearms, but then wants to play with Crosman in the cheap airgun market.

      • I have the rifle and i do have to say the mag isnt what this guy says it is, yes it feels to be the cheapest part of the gun but its far better than some mcdonalds toy or a crossman rifle.

    • I hope dig is not going down the same he as BMW. Had great driving and performance for years with 3 models and a few SUVs. Now the have, 1,2,3,4,5,6,7,x1,x3, x5. After 4 cars in a row with them, my last was a X3 with 4 cyl turbo sounded like a 1972 Vega. Had a suspension knock no one could find. They went from great to mediocre in 10 years trying to satisfy everyone and managed to satisfy no one.

  3. I just bought the Sig P226 in FDE IN .177 pellet. It’s ok but it’s also a 1st gen. I probably should’ve waited but love being a first adopter. /sari That said, the mag is cheap and doesn’t always cycle when the trigger is pulled.

  4. I did a fair amount of research and found an airsoft rifle that was very similar in weight, design layout and dimensions to my go-to rifle. No, it doesn’t incorporate a functional forward assist, bolt release or charging handle; but for the ability to set up multiple targets, engaging them inside the house (without anyone else around) and not worrying about damaging anything seems more true to life practice than anything I’d be comfortable doing with an air rifle.

    The targets I use are print-outs, taped to the open ends of cardboard boxes, with old t-shirts as backstops. There are some really well-spec’d airsoft rifles you can get for the $200-300 range that will enable you to train in ways most people can’t. I got an Apex Carbine Mk 13 Mod 5 to substitute for my Colt LE6945 in-between range days; with a charged battery and a clean barrel I can easily run 1″ groups at 25 yards.

    Unlike most non-firearms, m4-type AEG airsoft rifle internal parts are fairly universal and they are also serviceable.

    • The gas powered ones have functional charging handles and bolt hold open. Download mags to 30rds and you have one hell of a training analog. Is it perfect? Nah, but it’s miles ahead of this sig abomination.

  5. I’ve long bemoaned the fact that there isn’t a decent AR-style .177 or .22 semi auto pellet rifle for a reasonable price on the market

    • Unfortunately, even with a 90 gram CO2 canister, the SIG MCX Air Rifle only puts pellets down range at 750 fps (for reference, the Gamo Varmint Hunter is 1,250 fps). It’s been accurate enough to consistently hit cans at 20-50 yards and I’m sure you could put down small birds and the smallest of small game with a brand new can of CO2 installed. But once the CO2 starts to run low the pellets begin to lose velocity and drop quite a bit even at just 30 yards. If you’re looking for a varmint air gun, this probably isn’t a great choice.

  6. For $200 and carrying the SIG name, I expected more than what is described here, especially the magazine that looks like a mechanical nightmare. I appreciate the review and can now scratch that on off my want list.

  7. Happened into one of the ‘stealth’ arrivals myself…still shows out of stock at major sources but they must be trickling out slowly. Is the gun perfect? Of course not, but I do think after some plinking and getting to know the gun hands on that it is a great value if u want a well built/powerful/accurate true semi auto pellet rifle. Not really any gun on the market compares with its features/specs for $200. The mag is weird but it’s not as bad as noted here imho. There is a supplement in instructions that clearly explain proper removal and installation directions (once u get your perspective right with diagrams). A recent review on a professional crony I just read generated impressive #’s for co2. Nearly 750 fps with ultra lights and nearly 700 fps with 7 grains I beleive. They also pulled off very tight groups for what this gun is. I am an amateur and can pull of good groups myself. That’s hammerli 850 territory if I’m not mistaken without having to cock after each shot (i know..hammerli likely better built/more accurate but also more $).I added a bushnell red dot sight and it was a nice match for $65. I think people can pick one up with confidence and will enjoy it!

  8. I wonder, does this rifle actually have a rifled barrel like the cx4? and if so is it as the cx4’s produced by a major brand like walther?

  9. The gun looks nice however, for the $200.00 and once you decide to put on tactical add-ons, flashlight, laser, better forward grip etc, and laserdot your talking $500.00. Thats just crazy for a air rifle. Its advertised 750fps won’t be exactly true and I have read it comes in more like 500fps clocked. Is the fake suppressor metal? Of not I don’t see how it’s going to be balanced out with the co2 gram stock and metal receiver being all the weight in the back. If you want a fun gun get a Umarex Steel Force! At least it can be converted to full auto and has 6 shot burst.

  10. I have not ran a whole canister of Co2 yet I am using Gamo domed pellets and copperhead 7.9 wad cutters the gun has for lack of a better term jammed numerous times the magazine is very very difficult to remove when this happens almost like the mag release isn’t release properly the pellets are jamming in the belt feed I have tried ied t here different pellets I oiled the track with a light coating of oil no help I oiled the pellets with a very light drop of oil no help just wondering if a new mag or belt will help love everything else about the gun not sure if I turned the belt the wrong way and screwed something up going to try sig pellets if I can find them four out of five stars for the faulty mag release and pellets sticking in the belt

  11. You can put your seating tool in the handle of the SIG sauer mpx. It you look underneath the handle it say SIG and you can pop if open like a soda can and store your tool and pellet as well.

  12. If you own the SIG Sauer MPX or CMX you can store your seating tool in the handle; if you look underneath the handle there is a lid that pop open, and you can put your seating tool as well as pellets in there. It open up like a soda can lol! I hope that is useful to you consumers.

  13. Does anyone know about the problem of the co2 air leaking (when the trigger is pulled during a couple of shots? Every bit of the co2 air is lost during this problem. I can’t even get an RMA # sent to me. I must be doing something wrong about that certain process one has to go through to get it refunded/replaced after only 4 months, just about oh I’d say a good 7 full days use(5 co2 cartridges). If anyone could assist me in this problem, i sure would appreciate it! Thank you. JJD.

    • Sorry, I can’t answer your question, but I have just experienced the same problem. Literally 2 shots fired and the gun started dumping CO2 and I couldnt stop it so the whole £8 canister emptied out.

      Tempted to just get a refund rather than a repair – it’s hardly reassuring!

  14. Thought I would add my experience here. I have had 3 of the MCX Units.

    Purchased the MCX on May 1st- from Cabelas got it home and found three was no magazine in the unit and the sites were broken. I was shocked that it made it passed QC. I got an exchange unit from them the same day.
    1. Yes loading the pellets is kinda of a pain but not bad.
    2. Did notice that as you load pellets the magazine will actually leave marks embedded in the pellets, I think this is to make sure the pellet doesn’t fall out. I think this contributes to some low FPS readings.
    3. I do not use 88g C02 on this unit I tried one and it does not get good thread bite, especially Umerax 88g dont use them in this gun. I settled on JT 90g cylinders and have had no issues.
    4. I loaded mag with Benjamin lead hollow point rounds and setup targets at 10, 15, 25, yards.
    5. Loading mag to gun can be stiff and misalign slightly on this second gun.
    6. Fired 15 rounds from 25 yards back to 10, all hit there targets within a 2 inch grouping so not bad. The chrono showed FPS starting at 650fps, then consistently around 600. (little disappointing)
    7.The trigger and internal mechs it seems are noisy almost sounding loose when firing.
    8. Went fire 15 more rounds the gun let loose three pellets then on next shot C02 discharged from the trigger guard area and then blew the entire C02 contents out of the end of the barrel.

    Needless to say I was becoming unimpressed with this air rifle and its abilities. So back to Cabelas and on to unit number three. Now normally I would say enough but I did like some of the features of the gun and wanted to see if they could actually produce a good air gun I own a sig 9mm and there firearms are great.

    So on to gun number three:
    1. Everything was in the kit I did notice that the pellet seating tool was a small piece on the sight adjuster the unit I had before had a long rod. The pellets loaded much smoother in the belt on this unit but it still leaves marks on the pellet. On this unit I decided to load RWS hyper max pellets to see how the gun reacted to them.
    2. fired 15 rounds at the above mentioned distances.
    Trigger mech was not sloppy as first two.
    Could clearly tell the sound of air and pellet leaving barrel was much more robust on this gun than the previous two. The strike at the target was very audible, (I have my splat indicator targets setup on 1/2 cedar fence boards). To my surprise the pellets penetrated their full depth and more in the cedar boards at 25 yards. This is the air gun I would expect from Sig. The trajectory of the pellets was much flatter with this gun than the other two.
    The chrono was also showing much better numbers and consistency. Shot #1 707fps, #2 721fps, the other 15 shots never dipped below 701fps. After that a gradual drop off it fps was noticed, but I can say that I got 7 magazines out of a single cylinder. I would probably not push it past 6 next time as number 7 was just a waste of pellets.
    Now all that said the huge difference in QC issues between these 3 units is a bit worrisome for the buyer.
    I will say without reservation though that this 3rd unit has been very good. In a day I put over 2500 rounds of the RWS Hyper Max pellets thru this with 2 magazines and did not have had a single misfire, jam , or any other issue with operation, it is a fun plinker and yes at 15 yards it will take out a gopher who decides to pop his head up from the dirt mound.
    Overall I am very happy with this last unit it has not failed me since so knock on wood. I have put close to 4000 rounds thru it in a just a few days and it is working very well and no issues so far. I have the .22 version of the MCX on pre-order so as soon as I get it I will post info on it.
    Thank for all the great info on here!. Just thought I would put in a few cents worth.

  15. Just purchased one today and took it directly to the range. Directions for the magazines a little frustrating without better pictures to get the directions correct to avoid damaging the magazine. Thankfully there was a decent Youtube video that helped. Had somewhat limited time because I was also instructing, but put 60 rounds of Crosman wadcutters through without any problem using a Umerax cylinder. My comments would be similar to Brian T and his third rifle. Other people at the range were very interested, and one experienced shooter at first glance thought it was the real thing. Time will tell on the durability, but a very good first impression.

  16. I got my mcx back in December 2015. I live in southeast texas so it doesn’t get real cold here. Found out real quick that you can’t shoot fast because the gun will freeze up and dump the co2 in cold weather. After about 6 mths had to send gun in to get co2 seal replaced. Now less than 3 mths later the valve is not working correctly, having to pull changing handle 3 or 4 times per 30 shot string, leaving 4 to 5 pellets left in belt. With others jaming as a result of. Prior to this i have probably put around 5000 rounds through it. Have been using the daisey pointed precision max 7.9 grain pellets , with no problems up till now. tried gamo in the past , had multiple misfires with pellets jamming. In all i like the gun, but disappointed that I’m going to have to iether send back for repairs a second time or get a refund. Warranty is up in a few months and don’t want to end up with a 10 lb , 200$ paper weight. I’d like to see sig manufacture these guns themselves with the quality that sig is known for …….other than a Japanese sweat shop in a country that has banned all fire arms to the public without a special permission from the government and self defense does not qualify you as well as restrictions on air guns…… with unskilled workers building them…you would have a quality built rifle that you could depend on if built in U.S.

  17. I’ve long bemoaned the fact that there isn’t a decent AR-style .177 or .22 semi-auto pellet rifle for a reasonable price on the market

  18. I’m wondering why the original magazine that came with the rifle did not come with extra belts since ordering additional mags all come with THREE extra belts!


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