Building a 10.3″ MK18 is always alot of fun. Anything you like you can put it on, and the options are limitless.
In this ultimate build guide, we share the best MK18 parts list for anyone building a SBR (NFA) or a pistol (non-NFA).
You gonna get the whole list of parts to build this gun from top to bottom including recommended optics.
For most people, the MK18 build is really about optimizing a tactical CQB 10.3″ upper that works best in and around vehicle and tight spaces
Around approximately $1500, you can build yourself a bad ass short barrel MK18 with parts you want, or get the parts from our recommended AR parts.
Let’s get to it…
Ultimate MK18 MOD 1 Complete Parts List
- Spike Tactical Lower
- DD Stock/Grip Set
- Magpul UBR 2.0 (Buffer tube included) or VLTOR EMOD
- Geissele SDE Trigger – Trigger makes a huge difference, be sure to check out our best AR15 drop in trigger guide
- Anti Walk Pins
- Geissele Super 42 Braided Buffer Spring
- H2 Buffer (Normal Use) or H3 (Suppressed)
- Geissele Lower Parts Kit
- BCM AR Trigger Guard
- Magpul BAD Lever
- BCM Mil Spec Buffer Tube
For MK18 pistol builders, voiding NFA headaches by getting a pistol brace:
- SB Tactical SBA3
- Maxim Defense
Warning: Do not modify pistol brace configuration
Receiver brand doesn’t really matter as long as it’s from a reputable manufacturer and have proper Mil-Spec dimensions. Not all are made the same.
Most receivers are made at the same factory (Contiental Machine Tool) as any others, the difference is that the brand logo determines the price you pay.
Tip: You can tell where it is made by looking at the stamp on the receiver
Our favorites upper & lower receivers:
- Rock River Receiver
- Aero Precision
- Spike Tactical
If brand value is important to you, these are people’s favorite:
You can mix and match ! Enjoy
Upper Receiver MOD 1
- VLTOR or BCM Upper
- Bolt-Up System DD Barrel Nut Wrench
- DD factory BCG or Nickel Boron
- DD RIS II 9.55″ Rail
- DD 5.56mm 10.3″ Gov Barrel
- 0.070″ size Gas Block (unsuppressed)
- Carbine Length Gas Tube
- Geissele Airborne Charging Handle
- Forward Assist
- Surefire War Comp 556-1/2-28
Daniel Defense MK18 Build
The Daniel Defense MK18 is the official MK18 maker, and their rifles are adopted by the US spec ops in the global war on terror.
You can buy it or you can build it.
Easiest Option – Buy a Daniel Defense MK18 factory upper
The best thing that makes a DD MK18 is the unique RIS II quad rail, and there is no similar product on the market today:
If you want a legit DD MK18 specs ops are using the Daniel Defense RIS II rail is a must have handguard for your AR build.
DD RIS II Rail – The Real Deal!
- Battle proven 6 bolt bolt-up system securely attaches the handguard to the upper receiver
- 2 piece design accepts M203 grenade launcher without additional parts
- Seriously made for war
- 6061 T6 aluminum, durable & lightweight
- Free float system, increases accuracy
- Continous top rail
Having a durable optic for the MK18 is a must have item.
Iron sights are great, but almost no one shoots their MK18 in a series manner without using a red dot or magnified optic.
People love the Aimpoint Micro, EOTech, Trijicon MRO and ELCAN, and they are very commonly seen being used by real life military operations.
But there are more to see.
Difference Between MK18 MOD 0 & 1
Before the MK18 mod 1, this rifle configuration started with a basic M4A1.
First it was just a shorter barrel, then it was the CQBR upgrades that involved larger gas port for better cycling, better buffer system that are tweaked for each ammo type.
Finally the MK18 Mod 1, similar to the SOPMOD Block II, and it’s another iteration of the upgrade.
- No front sight
- Full length rail extends all the way to the base of the flashhider to have more rail real estate for accessories.
…and that’s the most modern and sexiest MK18 configuration that everyone talks about.
Which one you like the most, build that one!
You can go as expensive as you want, or go conservative, and the best part is you can always come back and tweak it.
MK18 MOD 0 Build
The most significant differences the MOD 0 has over other MK18 configurations are the upper and buffer system.
The upper is basically a shorter verison of the M4A1 with FSB flattop KAC RAS rail, larger gas port, and NT4 muzzle device.
The lower receiver For anyone that love the traditional M4A1 with the delta ring, KAC RAS Rail, and A2 front sight post, then MOD 0 is it.
MK18 CQBR Block 1
The MK18 CQBR uses surplus M16A1 lowers SOPMOD MK18 Build MK18 Stock Options (SBR vs Pistol)
For legal NFA SBR builders, they can put any stock on the rifle as long as your get your ATF form 1 or form 4 approval, and our favorites are:
- VLTOR CQBR Stock
- Magpul UBR
- Magpul MOE CTR