The rifle length spring lowers the velocity on the bolt carrier group allowing for less perceived recoil. On my personal MK18 that I use I have opted for the VLTOR A5 recoil system which in a nutshell is a rifle length spring with a variety of buffer weights to suit your needs. Or you can go with a heavier buffer weight or stiffer spring. You can install a gas block which allows you to change the amount of gas used to cycle your rifle, such as the excellent MicroMoa Govnah. If you want to fine tune your gas system you have several options available. The upside is that this rifle will run with any ammo and reliability will never be a concern with your MK18. It isn’t bad but it’s certainly something that is different from your standard 14.5 or 16 inch AR-15. The problem is that if you are using full powdered 5.56 you’ll have an excess of gas being spit back into your face around the charging handle and the gas port. It primarily exists from the time the bullet passes the gas port in the barrel to the time the bullet exits the muzzle.” – (The dwell time for the MK18 is horrifically short, to rectify this Daniel Defense opened up the gas port so that the gun is more forgiving of ammunition types like more weakly powered ammunition such as Tula. Incredibly rigid when installed yet weighing in at just 17.7 Oz, the RIS II M4A1 free float quad rail is the perfect option for clone-correct builds or anyone looking for the toughest rail on the market.“Dwell time is the time that your gas operated weapon maintains pressure to continue the cycling of the weapon.

Utilizing their patented Bolt-Up barrel nut system designed at the behest of the United States Special Operations Command for the SOCOM II program, the MK18 rail features an incredibly rigid two-piece design optimized for use with the standard M203 grenade launcher when the lower section is removed. One of the toughest and most effective rail systems for AR-pattern rifles available on the market to date.

10 inch quad rail mk18