Extension AR-15/M16 M4 Receiver Castle Nut

Name: Extension AR-15/M16 M4 Receiver Castle Nut
Brand: Ergo Grips

Ergo Grips · Buffer Tubes & Springs

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Extension AR-15/M16 M4 Receiver Castle Nut

Best price

$6.99at Battlehawk Armory

checked Oct 23, 2026

Buy at Battlehawk Armory

Compare 8 stores

Specifications

Manufacturer: Ergo Grips
Type: Buffer Tube
Platform: AR-15

Where to buy

Store	Price	Availability	Buy
Battlehawk Armory Best price	$6.99checked Oct 23, 2026	Check store	Buy at Battlehawk Armory
GrabAGun	$9.29checked Nov 12, 2026	Check store	Buy at GrabAGun
Classic Firearms	$9.31checked Nov 12, 2026	Check store	Buy at Classic Firearms
Palmetto State Armory	$9.49Salechecked Oct 22, 2026	Check store	Buy at Palmetto State Armory
Brownells 17.76% off · ends Nov 15 · exclusions apply	$9.29checked Nov 13, 2026	Out of stock	Buy at Brownells
OpticsPlanet	$9.99Salechecked Nov 12, 2026	Out of stock	Buy at OpticsPlanet
Ammunition Depot	$10.99checked Oct 23, 2026	Out of stock	Buy at Ammunition Depot
GunMag Warehouse	$13.99checked Oct 22, 2026	Out of stock	Buy at GunMag Warehouse

Prices and availability change often, so confirm on the store's site before you buy. We may earn a commission from these links.

Price history

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Lowest in-stock price in the last 30 days: $9.99 at OpticsPlanet. Dashed line = out of stock. Tracking since Sep 28, 2026.

Show the prices as a table

Store	Latest	Lowest	Highest
Ammunition Depot	—	$10.99	$10.99
Battlehawk Armory	—	$6.99	$6.99
Brownells	$9.29	$9.29	$9.29
Classic Firearms	$9.31	$9.31	$9.31
GrabAGun	$9.29	$9.29	$9.29
GunMag Warehouse	—	$13.99	$13.99
OpticsPlanet	$9.99	$9.99	$14.99
Palmetto State Armory	—	$9.49	$9.49

Since Sep 28, 2026.

About this part

The Extension AR-15/M16 M4 Receiver Castle Nut is an AR-15 buffer part from Ergo Grips. It's sold by 8 stores, from $6.99 to $13.99. The lowest in-stock price in the last 30 days was $9.99 at OpticsPlanet.