I see a lot of these while rearchimg an SBR build. What specific items make an MK18 or a MK18 clone?

The key is it is a 10.3" barrel. There are two versions out there. Mod 0 looks like an M4 with front sight base that was cut down to the proper length. The Mod 1 is the Daniel Defense Mk18. There are a few minor changes between what DD sells to the military and the civilian world, but the only noteworthy is the gas ports. DD opens them up to make sure the gun works with lower power loads like Wolf and Tula.

Out of curiosity, what is your plan?

The only for sure part of my plan right now is I've got a stamp for a form 1 SBR, a 10.5" 5.56 barrel and a Spikes lower. I also plan on using a Law folding stock adapter for whatever stock I end up choosing. Was looking at the Magpul ACS or ACS-L but now I'm finding others out there with a similar design that I like (BCM and some B5 so far).

Good possibility it will be suppressed at least part of the time. This is why I went with 10.5"

What was the purpose of going 10.3" vs 10.5"? Just to differentiate themsewilves and make it their own?

quote:

What was the purpose of going 10.3" vs 10.5"? Just to differentiate themsewilves and make it their own?

Crane cut the barrel as short as possible (still leaving the bayonet mount). Hence the 10.3".

The DD MK18 is actually closer to a CQBR than a MK18. Very few true MK18 lowers ended up in the CQBR configuration.