T
tehWildGingersmall things to mention
Reviewed on April 28, 2026Verified with Build
good stock but the adjustment lever was stiff for the first week of use
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Geissele AR15/M4 Reaction Block (Mil-Spec Buffer Tube Only) 05-314
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Geissele
Overview
The Geissele AR15/M4 Reaction Block is a Mil-Spec buffer tube designed as a tube only assembly, providing a reliable foundation for your AR-15 build. This buffer tube is critical for proper function and cycling of the action, ensuring compatibility with Mil-Spec components and accessories. Commonly seen in builds featuring a mid-length gas system and chambered in 5.56 NATO, this component is essential for achieving a smooth and reliable shooting experience.
Specifications
MPN05-314
AssemblyTube Only
Buffer Tube SpecMil-Spec
Frequently Built With
Based on build data
Bravo Company Manufacturing Mk2 Recoil Mitigation System - Mod 1 - T2
Sprinco Usa Reduced Power Kit Buffer 4-Coil Bolt Extractor Spring
Fortis Lightweight Enhanced AR-15 End Plate, Gold - LE-BLK-K1-GOLD
Radian Forward Assist - 7075 Aluminum - Black
Forward Assist
Jp Enterprises Silent Captured Spring for Law Tactical Folder
Geissele Automatics Llc Ar-15 Ultra Precision 5 Axis Trigger Guard Ddc
Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
PlatformBased on real build data showing which platform (AR-15, AR-10, AR-9) builders pair with this product.
93.8%
AR-1593.8%
AR-96.3%
CaliberBased on real build data showing which calibers builders choose alongside this product.
76.5%
5.56 NATO76.5%
.223 Wylde11.8%
.450 Bushmaster11.8%
Gas SystemBased on real build data showing which gas system lengths builders use with this product.
57.9%
Mid-Length57.9%
Carbine21.1%
Rifle15.8%
Pistol5.3%
| Product | Category | Times Built Together |
|---|---|---|
| Bravo Company Manufacturing Mk2 Recoil Mitigation System - Mod 1 - T2 | 12 | |
| Sprinco Usa Reduced Power Kit Buffer 4-Coil Bolt Extractor Spring | 9 | |
| Fortis Lightweight Enhanced AR-15 End Plate, Gold - LE-BLK-K1-GOLD | 9 | |
| Radian Forward Assist - 7075 Aluminum - Black | Forward Assist | 8 |
| Jp Enterprises Silent Captured Spring for Law Tactical Folder | 8 | |
| Geissele Automatics Llc Ar-15 Ultra Precision 5 Axis Trigger Guard Ddc | 8 |
| Platform | Percentage |
|---|---|
| AR-15 | 93.8% |
| AR-9 | 6.3% |
| Caliber | Percentage |
|---|---|
| 5.56 NATO | 76.5% |
| .223 Wylde | 11.8% |
| .450 Bushmaster | 11.8% |
| Gas System | Percentage |
|---|---|
| Mid-Length | 57.9% |
| Carbine | 21.1% |
| Rifle | 15.8% |
| Pistol | 5.3% |
Builds Featuring This Part
See all 5 →Builds in the community that include the Geissele AR15/M4 Reaction Block (Mil-Spec Buffer Tube Only) 05-314
| Build | Parts | Total |
|---|---|---|
 | 25 | $2495.43 |
 | 28 | $5330.29 |
 | 24 | $3653.74 |
 | 32 | $2612.49 |
 | 36 | $16188.80 |
Customer reviews
4.0out of 5
2 global ratings
Top reviews
I
i_likebuilding91Geissele reaction block heavy
Reviewed on March 26, 2026Verified with Build
Geissele AR15 reaction block fits a milspec buffer tube. Used for clamping uppers in a vise without marring. Heavier than I expected from a small accessory but the solid steel construction is reassuring. Worth it if you do your own armorer work.
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