Jacob Grey Logo

Jacob Grey 9mm Complete Upper Assembly 4.5″




Made in the USA

7075-T6 Mil-spec Upper Receiver

1:10 Twist Rate

1/2×28 Thread Pattern

4″ Jacob Grey 7-sided M-Lok Hand guard

Knurled JG 6 Point Directional Compensator

9mm Bolt Carrier Group and Charging handle Included

Class III Type 2 Hard coat anodized finish

9mm Specific Upper receiver with reduced ejection port for smaller rounds

Jacob Grey’s unique checkering design specific to the JG-9 platform

Designed to match lines with Jacob Grey JG-9 & JG-15 Billet Lower however will fit with any Mil-spec lower receiver.

Contains integrated Last Round Bolt Hold Open (LRBHO) technology that reliably holds the bolt open when magazine is empty

LRBHO feature is designed for lowers that accept Glock style magazines


Share With Your Friends:



9mm JG-9 upper receiver with 4″ mlok hand guard, 9mm bolt carrier group, JG 9mm 4” 4150 chrome moly vanadium steel barrel, JG ambidextrous charging handle and JG knurled 6 point directional compensator included

**NOTE — This upper is machined for a gas tube although it is intended for blowback gas systems only

Once assembled the small “hook” end of the wire form in the upper should be pushed up by the follower of an empty Glock magazine which will engage the bolt catch on the last round fired to hold the bolt in the locked position. If it does not engage or engages before the last round is fired, you can make VERY SMALL adjustments by SLIGHTLY bending the “hook” end down to lock faster or up to lock slower.  They are set and function checked during assembly with brand new Glock magazines and our standard bolt catches.  Because of varying magazine specs, magazine specs changing over the life of the product, different thicknesses of the pad on the bolt catch and other variables, this adjustment may be necessary with your specific parts.


**NOTE:  Some rail systems that use anti-rotation tabs may need slight modification to fit this upper.  It is designed for flush mounting rails and standard hand guards.




There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

Other Products You Must Have


Go to Top