The AR-15 Rear Base Spring – 3 Required (DPMS, SKU 231000141) is a small but crucial component of the AR-15 A2 rear sight assembly, responsible for maintaining proper tension and repeatable adjustment on your iron sights. Manufactured by DPMS Firearms LLC and sold as the AR-15 Rear Base Spring 3 Req’d – Unfinished, this OEM-spec spring is designed for use in classic fixed carry-handle uppers and A2-style rear sights used on many AR-15 rifles and carbines. Brownells+2Graf & Sons+2
Whether you’re rebuilding a service rifle clone, restoring an older DPMS, or just stocking critical spares, these springs help keep your rear sight base tracking smoothly and holding zero the way it should.
OEM DPMS AR-15 A2 Rear Sight Base Spring
This part is listed by DPMS and major distributors as the AR-15 Rear Base Spring 3 Req’d, Unfinished, with Brownells part #231000141 and manufacturer part #F1000804 (REAR BASE SPRING, 3 R). Brownells+2Brownells+2
Key points:
Genuine DPMS small part – not an off-brand substitute
Designed specifically for the AR-15 A2 rear sight base
Marked “Rear base spring, 3 required” in OEM listings, indicating that three springs are needed per rear sight assembly Graf & Sons+1
Using original-spec springs helps ensure your rear sight operates with the crisp clicks and consistent tension intended by the A2 design.
What the Rear Base Springs Do in an A2 Sight
In an A2-style AR-15 rear sight, the base springs provide the small, controlled tension that keeps the rear sight base properly biased and helps maintain:
Positive windage and elevation adjustments
Stable sight alignment under recoil and normal handling
Return-to-position consistency when you dial your sight for different ranges and then come back to your zero
Because they’re small and constantly under tension, these springs can fatigue, deform, or get lost during disassembly. Keeping quality replacements on hand makes it easy to bring a mushy, inconsistent A2 rear sight back to life.
Compatible with DPMS & Other A2-Style AR-15 Uppers
This DPMS rear base spring is designed for AR-15 rifles with A2-style rear sights, including DPMS models and many other mil-spec pattern builds. Distributor listings group this part under AR-15 rifle sights & parts, and it’s commonly used on DPMS rifles such as the M4 Post Ban 16", Panther Classic, and Panther Classic 16" that use A2 iron sights. Brownells+2Primary Tactical+2
In general, it’s suitable for:
Fixed carry-handle uppers with A2 rear sights
Detachable A2-style carry handles that follow standard AR-15 dimensions
Service rifle clones and classic-style builds that retain the robust A2 iron sight system
As with any small part, compatibility depends on your specific upper and sight assembly, but this is a standard DPMS mil-spec style spring widely used across AR-15 A2 configurations.
Unfinished Steel – Ready for Work, Not for Show
Retailers list this part as “Color: Unfinished”, indicating a straightforward, functional small steel spring, not a coated or plated decorative component. Frisco Guns+2Bullets and Brass Website+2
Benefits of the unfinished construction:
Purpose-built for internal use inside the A2 rear sight base
Designed to sit protected within the sight assembly, away from direct impact or cosmetic scrutiny
Easy to lightly oil along with the rest of your sight components to prevent corrosion
This is a classic function-first AR-15 small part—you’ll rarely see it, but you’ll definitely notice if it isn’t doing its job.
Ideal for Repairs, Restorations & Spare Parts Kits
Because the rear base spring is a wear-and-tear item, having replacements on hand is smart insurance for any AR owner who relies on A2 irons. This DPMS AR-15 Rear Base Spring (3 Req’d) is ideal for:
Repairing a loose or inconsistent rear sight
Restoring older DPMS or AR-15 rifles with worn or missing springs
Building or rebuilding A2-style uppers and carry-handle assemblies
Stocking armorer’s and range spare parts kits so a tiny spring never sidelines a rifle
At this small price point, it’s one of the most cost-effective parts you can keep in your toolbox to prevent downtime and maintain accuracy on rifles that use A2 iron sights. Brownells+2Frisco Guns+2
High-Value, Low-Cost Reliability Upgrade
Swapping in fresh, correct-spec springs can restore:
Crisp, repeatable click adjustments
Improved return to zero after changing elevation
More secure sight base tension, reducing wobble or drift over time
It’s a quick way to tighten up an otherwise solid rifle whose only flaw is a tired A2 rear sight.
Note: As with all AR-15 sight and small-part work, installation should be performed carefully. If you are unsure about disassembling your rear sight assembly, consult a qualified gunsmith or armorer.
Key Features & Specifications – AR-15 Rear Base Spring 3 Req’d (231000141)
If you’re maintaining or building an A2-style AR-15 and want your iron sights to track cleanly and hold zero the way they were meant to, the DPMS AR-15 Rear Base Spring – 3 Required (231000141) is the OEM-spec replacement part that keeps your rear sight base tensioned, reliable, and ready for serious use.
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