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Questions & Answers
Customer Reviews
Helpful Positive Review
Excellent Product by painlez, Verified Owner, August 20, 2023
The geissele Reaction Block is well engineered & produced to the highest standards, like all Geissele products. It is not inexpensive but I guarantee you will get your money's worth over the long haul!!! It is sturdy and functions as described...
1/1 found this helpful
Helpful Positive Review
Geissele AR-15 Reaction Block by Rob, Verified Owner, October 26, 2023
This is an excellent item that holds the buffer tube when tightening the castle nut. I like it because all the stress and torquing stress is on the buffer tube and not the lower receiver. This is especially helpful when you are trying to remove a stu...
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2/2 found this helpful
Helpful Positive Review
A must for professional level installation by Andy, Verified Owner, September 25, 2020
If you are happy having a crooked buffer tube when torquing the castle nut then this isn't for you. If you're only going to be building one rifle maybe this isn't for you. But... if you work on a lot of AR15s this is a must for a perfectly aligned ...
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1/1 found this helpful
Helpful Positive Review
I was completing two new rifle builds and wanted to upgrade my tools. OP had the Reaction Block on sale and after looking at some reviews on YouTube, I decided to give it a try and I'm glad I did! It was perfect for the trigger install and trigger gu...
Read More...
1/1 found this helpful
Helpful Positive Review
I was completing two new rifle builds and wanted to upgrade my tools. OP had the Reaction Block on sale and after looking at some reviews on YouTube, I decided to give it a try and I'm glad I did! It was perfect for the trigger install and trigger gu...
Read More...
1/1 found this helpful
Most Recent Reviews
No comparison by Team G, Verified Owner, July 17, 2025
I looked at other options but kept coming back to this. Yes it cost a lot more than the competitors but made working in vice easy and didn’t mar or scrap finish
Read All 14 Reviews
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Color: Black Gun Model: AR-15 , M4 Condition: New

Code: 1TO-RBT-05-314-EE

MPN: 05-314

UPC: 854014005984

12%
Product Discount
List: $241.38Save 15%
$204.00

made-in-usa-flag Made in USA

Help support American manufacturing! Marked models of this product have gone through rigorous review and been certified by the manufacturer as Made in the USA.

Product Info for Geissele AR15/M4 Reaction Block

The Geissele Reaction Block is designed to aid in the assembly of lower receivers. Once the armorer has installed the buffer tube, the lower receiver can then be slid into the Reaction Block at the 12, 3, 6 and 9 o'clock positions. This allows the armorer to rotate the lower receiver by 90° increments in the block simply by loosening the provided nylon screws, removing the lower receiver and sliding it back in at its desired orientation. The Reaction Block provides an ultra-stable platform for performing an array of lower receiver operations as well as making the installation of the buffer retainer nut quick and easy. This is all possible while keeping both hands of the armorer free to work, saving both time and frustration.image

WARNING: California`s Proposition 65

Specifications for Geissele AR15/M4 Reaction Block:

Manufacturer: Geissele
Color: Black
Gun Model: M4, AR-15
Condition: New
Country of Origin: USA

Package Contents:

  • Geissele AR15/M4 Reaction Block

Geissele AR15/M4 Reaction Block Orderable Models

List of Orderable Models

  • Geissele AR15/M4 Reaction Block,Mil-Spec Buffer Tube Only 05-314 , MPN: 05-314 , UPC: 854014005984 , Code: 1TO-RBT-05-314-EE

Geissele AR15/M4 Reaction Block Unavailable & Discontinued Models

List of Unorderable Models

  • DEMO, Geissele AR15/M4 Reaction Block,Mil-Spec Buffer Tube Only 05-314 , MPN: 05-314-DEMO , Code: 1TO-RBT-05-314-DEMO
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