AR-15/M16 UPPER RECEIVER ACTION BLOCK

AR-15/M16 UPPER RECEIVER ACTION BLOCK Reviews & Ratings

AR-15/M16 UPPER RECEIVER ACTION BLOCK

Heavy-duty blocks allow you to firmly clamp AR-15/M16 receiver halves in a vise without risk of crushing, twisting, or otherwise distorting them when applying vise pressure or torquing the barrel nut. Keeps your rifle secure for safe, effective cleaning, assembly, and repair. High pressure, solvent resistant, structural Rynite block and insert surround the entire upper receiver and support it inside and out to make rebarreling the AR-15/M16 an easy, one-man job. Lets you firmly secure a mil-spec carry handle receiver or mil-spec flattop receiver in a large bench vise for barrel removal/installation. Torque generated while tightening the barrel nut is transmitted to the block and insert, not the receiver. Minimizes the possibility of damage to the barrel detent pin and receiver detent notch. Holds securely without marring the finish.

DO NOT USE ON BILLET UPPERS OR LEFT HAND UPPERS, OR DAMAGE TO THE UPPER CAN RESULT.




SPECIFICATIONS:

  • Material: Injection-Molded Rynite
  • Color: Black
  • Fits: A1, A2 and Standard Flattop Receivers
  • Block:
    • Thickness: 2-1/2"
    • Width: 3-1/2"
    • Height: 4-1/2"
  • Insert:
    • Length: 8"
    • Diameter: 1"
  • Torque Tested to 200 ft. lbs

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5 Stars
70%
4 Stars
13%
3 Stars
9%
2 Stars
4%
1 Stars
4%
Reviews Summary
Overall, the AR-15/M16 Upper Receiver Action Block receives mixed reviews. While many users praise its sturdy build and ease of use, some report fitment issues with certain brands. Overall, it's considered an essential tool for DIY modifications, though quality control could be improved to ensure compatibility across more receiver types.
What Reviewers Are Saying
Product Fit
40%
Several reviewers express concerns regarding the fit of the action block on various upper receivers, particularly noting issues with non-milspec brands like DPMS and others. While some found the snug fit beneficial, others had to customize or modify the block for better compatibility, indicating a variance in quality control.
Ease of Use
65%
Many users commend the action block for its ease of use, noting that it securely holds the upper receiver in place during assembly or maintenance tasks. This feature is highlighted as a major advantage, making barrel changes and other modifications straightforward and manageable for DIY enthusiasts.
Quality and Durability
50%
The build quality of the action block is generally seen as solid and durable, with several reviews highlighting its non-marring material that protects the finish of the upper receiver. However, there are mentions of variability, with some users dissatisfied with the quality control associated with their specific units.
Essential Tool
70%
Numerous reviews categorize this action block as an essential tool for anyone working on AR-15s or M-16s. Its utility is well-recognized among DIY rifle owners, as it helps to prevent damage to receivers and simplifies tasks like installing barrels or handguards.
Price Value
60%
Reviewers frequently comment on the competitive pricing of the action block, considering it a great value for the features and reliability it offers. Many believe it is worth the investment for the quality of service it provides during firearm maintenance.
3
Upper receivers didn't fit.
Block Wouldn't come close to closing on an AERO M4E1 or any standard Mil-Spec Upper. Had to file and grind on it for a few hours with my Dremel just to get it to close enough so I could torque down my barrel. Quality Control is terrible. Wouldn't recommend unless you feel like wasting a few hours grinding on something that should have been done right in the first place. 🤦
by Jeffrey C. on March 08, 2026
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3
think molds need attention
does not fit my mil spec upper, seems like the "handle" area is way too tight to accept the upper, cannot close all the way, will need to shave the inner areas to make this work correctly. expected higher quality control from Brownells name brand blocks
by Bill W. on March 06, 2025
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