Strike Industries End Plate and Anti-Rotate Castle Nut for Receivers, Red - SI-AR-UL-MFEP&ACN-RED

Strike Industries End Plate and Anti-Rotate Castle Nut for Receivers, Red - SI-AR-UL-MFEP&ACN-RED - End Plate for AR-15 - view 1
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Strike Industries

Overview

The Strike Industries End Plate and Anti-Rotate Castle Nut is a standard steel component designed to secure the buffer tube to the receiver while preventing any rotational movement. This combination provides a reliable foundation for your AR-15 build, ensuring that the buffer tube remains aligned during operation. You will often find this end plate and castle nut set used in mid-length gas system builds chambered in 5.56 NATO, where durability and stability are essential.

Specifications

MPNARULMFEP&ACNRED
TypeStandard
MaterialSteel

Available Merchants(6)

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Frequently Built With

Based on build data

Build Configuration Breakdown

Aggregated and anonymized data showing how builders use this product

Platform

60%
AR-1560%
AR-1040%

Caliber

33.3%
.223 Wylde33.3%
.308 Win16.7%
.450 Bushmaster16.7%
300 Blackout16.7%
5.56 NATO16.7%

Gas System

60%
Mid-Length60%
Pistol20%
Rifle20%
Frequently Built With Products
ProductCategoryTimes Built Together
Rise Armament Ar-15 Magazine Release Button - Rise Red142
Strike Industries Cobra Billet Aluminum Trigger Guard - Red136
Timber Creek Outdoors Ar-15 Takedown Pin Set - Red119
Strike Industries Carbine Length Pistol Buffer Tube - Red113
Strike Industries Ar-15 Ambidextrous Safety Selector Switch - Red100
Strike Industries 7075 T6 Aluminum AR Pistol Buffer Tube, Red - ARSPRESLICKRED84
Build Platform Breakdown
PlatformPercentage
AR-1560%
AR-1040%
Build Caliber Breakdown
CaliberPercentage
.223 Wylde33.3%
.308 Win16.7%
.450 Bushmaster16.7%
300 Blackout16.7%
5.56 NATO16.7%
Build Gas System Breakdown
Gas SystemPercentage
Mid-Length60%
Pistol20%
Rifle20%

Builds Featuring This Part

See all 20

Builds in the community that include the Strike Industries End Plate and Anti-Rotate Castle Nut for Receivers, Red - SI-AR-UL-MFEP&ACN-RED

BuildPartsTotal
SBR 14.5" 5.56
30$5221.96
for the family fun 16"
27$2127.33
LMT 16"
28$2601.51
Carbine 16" 5.56
37$6257.33
my build
22$2911.07
As a truck gun 30"
19$660.63
14.5" build
25$1889.81
DMR 16" 5.56
22$1989.10
SBR 16" 5.56
34$4624.85
14.5" SBR
24$1519.18
6" 5.56
22$1231.53
14.8" PSA carbine
19$493.53

Customer reviews

4.5out of 5

4 global ratings

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Top reviews

J
Jamie23300
Good value and strong
Reviewed on May 12, 2026Verified with Build

Secured my buffer tube on my new 5.56 build with absolutely zero issues. This thing is built solid and the anti-rotate feature is a smart addition. Couldn't ask for more from a basic AR component like this.

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C
CoolBreeze
Functional but nothing special
Reviewed on May 9, 2026Verified with Build

It's an end plate and castle nut set. Does what it's supposed to do by keeping the buffer tube in place. The steel feels standard, not premium but not flimsy either. The red color adds a bit of pop.

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J
Jando_pdw
Excellent anti-rotation design
Reviewed on April 6, 2026Verified with Build

Was looking for a reliable way to keep my buffer tube from spinning during installation and operation. This SI set does the job perfectly. The castle nut staked well and the end plate design prevents any wobble. Great for AR builds.

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C
Catchdog64_pdw
Solid end plate, minor color issue
Reviewed on March 4, 2026Verified with Build

This Strike Industries end plate and castle nut feels sturdy enough. The red color is a nice touch for my build, though it was slightly darker than I expected from the photos online. Overall, it holds the buffer tube securely.

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