Block II Colt Upper Clone

Give your MK18 or M4A1 Block II clone the finishing touch.

Starts from a new stripped Colt Keyhole upper receiver with factory-installed forward assist and ejection port door, then custom engraved by Shadow Strategic in the style of reference MK18 Block II and M4A1 Block II.

Each upper can be personalized with up to 15 custom characters. Choose your engraving position and font style to match the look you want for your clone build.

Due to the wide range of real-world Block II markings, we selected font styles based on the clearest reference photos available.

Please allow up to 5 business days for engraving and processing.

Customization Options

At checkout, please choose:

• Colt upper type
• Custom engraving text — up to 15 characters
• Engraving position — Forward, Center, or Rearward
• Font style — C, X, or 1

Example:

Rearward / Font C
Forward / Font X
Center / Font 1

Important Notes

This listing is for the upper receiver only, as pictured, with forward assist and ejection port door installed from the factory.

Our cage code is engraved on the inside of the upper to designate that the custom engraving was performed by Shadow Strategic. This is mandatory to prevent these receivers from being misrepresented as surplus, military-issued, or contract-origin uppers.

These are new stripped Colt upper receivers. Minor factory handling marks or cosmetic blemishes may be present due to how they are received from the manufacturer.

Disclaimer

Base upper receiver is manufactured by Colt. Shadow Strategic performs custom engraving only.

Shadow Strategic is not affiliated with, endorsed by, or sponsored by Colt, Daniel Defense, or any government agency. References to “Block II,” “MK18,” “M4A1,” “Colt,” or similar terms are for compatibility, historical, and descriptive purposes only.

Custom engraving is decorative and does not indicate military issue, contract origin, or official affiliation.