Product Information

10.3 MK18 (Crane Spec)
Our 10.3" Crane Spec complete upper receiver features the ideal gas port sizing (.070) to achieve minimal gas blowback when ran suppressed. This unit is specifically designed to be ran in conjunction with a silencer. 
We do not guarantee reliable cycling with some manufactures ammunition without the addition of a silencer. 
Our MK18 Crane Spec is shipped as pictured, just add your preferred silencer mount, drop in handguard and rear sight (which aligns perfectly with our F marked FSB!


* (Not Included) Standard Charging Handle & M16 BCG HP/MPI Tested with Viton O-ring


- 10.3" 4150 CMV Melonite

- 1/7 Twist

- .070 Gas Port

- M4 Feed Ramps

- Carbine Length Gas System with F-Mark Front Site Base

- Front Site & Sling Swivel

- Delta Ring Assembly

- QPQ Corrosion Resistant Finish

- 1/2-28 Thread

- Dry Film Lubed Upper w/ T-Markings

- Forward Assist & Ejection Port Assembly


*When choosing a Cerakote Package, please allow for an additional two weeks for delivery. The Cerakote Package includes the Cerakote of the upper receiver as well as the forearm. If any other parts are needed to be Cerakoted, please email

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