Sig Sauer MCX and KeyMod System
Making a change to accessories
By Dennis Adler
It’s Thanksgiving and so this is going to be a short read, but one that answers a very good question about the Sig Sauer MCX CO2 semi-auto tactical rifle. It has a foregrip that comes mounted to the handguard and for some it is positioned too far back on the handguard rail. I found the factory mounting position good because it is far enough back that it helps push the support arm into the body for a more solid hold. But if you have longer arms it could be too close.
The centerfire Sig Sauer MCX model uses a KeyMod system handguard which is designed for the rapid mounting and dismounting of accessories and accessory rails. Developed around 5-years ago, the KeyMod looks like a series of keyholes into which any accessory with a machined mounting screw and nut or (two or more) can attach and be solidly locked into place. This eliminates the need for full length Picatinny rails on rifles like the MCX and AR-based designs, as shorter rails can be mounted wherever needed on the top, sides or bottom in seconds, or an individual component, like a foregrip can be easily attached.
The Sig Sauer MCX CO2 model uses a real KeyMod design handguard and a foregrip that locks into place using Phillips head screws (rather than hex head screws used on actual KeyMod accessories) but works in the same way. At first when the question was asked, I doubted that the CO2 model had an actual working KeyMod foregrip because of the different screws (Phillips head) and the look of the nut inside the handguard. But, in fact, it works the same and you can move the foregrip by slightly loosening the two Phillips head screws so that the nuts at the top of foregrip can slide back and out of the KeyMod slot, allowing the foregrip to be removed by pulling it straight down and out. Then just place it where you want it, push the nuts up into the large keyhole slots, slide it forward into the narrower slot and screw it down. All very simple if you are familiar with the KeyMod system and go with the assumption that the foregrip on the CO2 model can be removed the same way. After a quick call to Sig I found out that it could and then followed the same process as any KeyMod handguard and accessory.
If you don’t have the Sig Sauer MCX CO2 model, this probably isn’t all that helpful, but it might also seal the deal if you’re on the fence. This is one powerful (88 gram) CO2 powered, pellet-firing air rifle and it can be equipped as shown or with any accessory that fits on a centerfire model. It is a practical tactical trainer and will give you a feel for the real gun and using the KeyMod system to mount accessories.
Happy Thanksgiving! This Saturday we take the two most interesting CO2 pellet cartridge firing WWI era revolvers, and shoot them head-to-head. It’s going to be one very revealing airgun test!