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Dirty Bird SBA4 Lower Build Kit

Dirty Bird SBA4 Lower Build Kit

Dirty Bird · Lower Receiver

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Best price

$179.95at AR15Discounts

checked Oct 31, 2026

Buy at AR15Discounts

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Where to buy

StorePriceAvailabilityBuyAdd to build
AR15Discounts Best price $179.95checked Oct 31, 2026 Check store Buy at AR15Discounts
Dirty Bird $219.95checked Oct 31, 2026 Check store Buy at Dirty Bird

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

Dashed line = out of stock. Tracking since Oct 28, 2026.

Show the prices as a table
StoreLatestLowestHighest
AR15Discounts$179.95$179.95$179.95
Dirty Bird$219.95$219.95$219.95

Since Oct 28, 2026.

About this part

The Dirty Bird SBA4 Lower Build Kit is a lower receiver from Dirty Bird. It's sold by 2 stores, from $179.95 to $219.95.

Specifications

Manufacturer
Dirty Bird

From the manufacturer

The Dirty Bird Industries SBA4 Lower Build Kit includes everything needed to finish your AR Pistol Lower Receiver using the ever popular SB Tactical SBA4 Stabilizing Brace. This kit includes the Dirty Bird enhanced Lower Parts Kit which features our 5-star rated Nickel Teflon Single Stage Trigger Group. This trigger features honed and polished engagement surfaces, a slick and durable Nickel Teflon finish and finely tuned trigger / hammer spring rates. This means you get a smooth trigger pull with very little take-up and a crisp clean break at 5 - 5.5 pounds. Additionally you'll get an enhanced polymer trigger guard and an extra takedown / pivot pin detent and spring in case one gets lost during installation. The kit also includes the Dirty Bird AR-15 True Mil-Spec Carbine Receiver Extension / Buffer Kit. This popular buffer kit features a true Mil-Spec 6-Position Receiver Extension (buffer tube) machined from American Made 7075-T6 Aluminum, 3oz Carbine Recoil Buffer w/ steel counter weights, a chrome silicon buffer spring, hardened castle nut with staking cuts and mil-spec end plate. Because there are so many grip options on the market and shooters are so different in their preferences, we've opted to simply include an A2 pistol grip as a part of the kit. This gives you something that is perfectly functional but doesn't really add to the cost of the kit and enables you to choose whatever grip you'd like for your build. Each component in this kit, down to the springs and detents are sourced from the best of the best and they're all 100% American Made. Includes: SB Tactical SBA4 Pistol Stabilizing Brace Dirty Bird AR-15 True Mil-Spec Carbine Receiver Extension / Buffer Kit 7075-T6 Aluminum 6-Position Mil-Spec Receiver Extension (7075-T6 Aluminum is nearly twice as strong as 6061) 3oz Carbine Recoil Buffer w/ Steel Counter Weights Hardened Castle Nut w/ Staking Cuts Mil-Spec End Plate Dirty Bird Enhanced Lower Parts kit Nickel Teflon Trigger Group - Nickel Teflon Honed and Polished Trigger and Hammer - Enhanced Disconnector - Disconnector Spring - Trigger Spring - Hammer Spring - Trigger / Hammer Pins (x2)Bolt Catch Kaw Valley Precision Reduced Power Springs Magazine Catch Magazine Catch Button Safety Selector Enhanced Polymer Trigger Guard (w/ set screw) Trigger / Hammer Pins (x2) Takedown Pin Pivot Pin Takedown / Pivot Pin Springs (x3) Takedown / Pivot Pin Detents (x3) Safety Selector Detent Safety Selector Detent Spring Magazine Catch Spring Trigger Guard Roll Pin Bolt Catch Detent Bolt Catch Detent Spring Bolt Catch Roll Pin Buffer Retainer / Detent Buffer Retainer / Detent Spring A2 Pistol Grip Assembly

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$179.95 at AR15Discounts
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