Building a 10.3" MK18 is always alot of fun with limitless AR accessories to choose from.
In this ultimate build guide, we put together a best MK18 parts list for anyone building a SBR (NFA) or a pistol (non-NFA). It includes everything so you don't have to look anywhere else on the internet.
For around approximately $1500, you can build a bad ass MK18 with exact parts you want, and you can upgrade it even more later.
Let's check them out...
Top 22 Parts To Make A MK18 Clone
- Spike Tactical Lower (Any receiver will do)
- 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
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
Please check out our upper receiver guide for more info.
For your MK18 build, just stick with a mil-spec receiver for the best fit.
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Our favorites upper & lower receivers:
- Rock River Receiver
- Aero Precision M4E1
- Spike Tactical
If brand value is important to you, these are people's favorite:
You can mix and match !
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- VLTOR or BCM Upper
- Bolt-Up System DD Barrel Nut Wrench
- DD factory BCG or Nickel Boron
- DD RIS II 9.55" Rail (Must Have!) Or Geissele MK8 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
The Daniel Defense MK18 is the official MK18, the looks and the feel of the DD RIS II handguard rail REALLY makes rilfe for what it is.
You can buy it or you can build it.
Easiest Option - Buy a Daniel Defense MK18 factory upper and build a pistol lower.
Or purchase the factory MK18 pistol. (Local FFL Transfer Required)
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:
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
The EOTech EXPS3 and ELCAN just really make the MK18 for what it is, but there are tons of other options available.
Difference Between MK18 MOD 0 & 1
The MK18 MOD 0 development all started with a basic M4A1.
First it was just a shorter barrel, then it was the CQBR upgrades that added a larger gas port for better cycling, improved buffer system that are optimized for each ammo type.
Finally the MK18 Mod 1 is born, similar to the SOPMOD Block II, now the rifle has plenty of rail space for mounting accessories thanks to the free float RIS II handguard.
- No front sight
- Full length rail extends all the way to the base of the flashhider to have more rail real estate.
...and that's the most modern MK18 configuration exists today.
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 configuration is the upper and the 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