My Account (Sign in)
Your basket is empty.
0
Basket
contact us by phone Help and contact
Free standard delivery over £199
100-day return policy
My Account (Sign in)
Wish list
Your basket is empty. (0)
Basket
Newsletter Newsletter
Sale

Over 300,000 customers - we say thank you!

4.93/5 "Very good" (1400+ reviews)

40,000+ products for hunting and shooting sports

Rifle Parts Receiver Parts Recoil Parts Recoil Springs SPRINCO USA SPRING KIT-XP BUFFER W/ HD 5-COIL BOLT EXTRACTOR SPRING Support

Enhance your M4 carbine's reliability with the SPRINCO USA Extra Power Buffer Spring, designed for optimal performance in various calibers including 6.8 SPC.

SPRINCO USA SPRING KIT-XP BUFFER W/ HD 5-COIL BOLT EXTRACTOR SPRING

657780250066 943000029
Variations
Filters:
Variations:

Variations:

Enhance your M4 carbine's reliability with the SPRINCO USA Extra Power Buffer Spring, designed for optimal performance in various calibers including 6.8 SPC.
M4 CARBINE/6.8 CS SPRING KIT - SPRING KIT-XP BUFFER W/ HD 5-COIL BOLT EXTRACTOR SPRING
40.9 GBP 0 £40.90 *
Backorderable
Product no.: 943000029
Backorderable
40.9 GBP 0 £40.90 *
Enhance your M4 carbine's reliability with the SPRINCO USA Red spring, offering 25% more power for improved function across various calibers.
M4 CARBINE/6.8 CS SPRING KIT - SPRING KIT-XP BUFFER &ENHANCED 4COIL BOLT EXTRACTOR SPRING
40.9 GBP 0 £40.90 *
Backorderable
Product no.: 943000030
Backorderable
40.9 GBP 0 £40.90 *
40.9 40.9 2 GBP
40.9 GBP £40.90

Prices inclusive of duty & VAT.

Product no.: 943000029

Mfr. No.: 25006

657780250066 Extra Power Buffer Spring. This was Sprinco's first AR buffer spring solution that they were tasked to design back in 2006 for a Force Modernization Team to specifically address spring-related M4 carbine reliability function issues for operating challenges in the Eastern Asia Theatre. The design loads of the Red spring are approximately 25% greater than the White spring for one of the considered Load Constants in the spring design. Refer to provided tuning procedure reference documents prior to calling for recommendations for use. The Red spring is commonly used in 9mm, 6.8 SPC, 6.5 Grendel, .450 BM, .450 SOCOM, .500 Beowulf, and Colt LE6920’s specimen carbines, but certain specimen guns can deviate from the norm depending upon port values and the power factor of your chosen ammunition loads.
Backorderable
Be the first to rate this product
1
2
3
4
5
6
7
8
9
10+
£40.90

Prices inclusive of duty & VAT.

1
2
3
4
5
6
7
8
9
10+

Backorderable, delivery time approx. 4-12 weeks from the USA warehouse.

100-Day Return Policy

Backorderable, delivery time approx. 4-12 weeks from the USA warehouse.

100-Day Return Policy
No charges until we ship
No charge:
Your credit card will not be charged when you place your order.

No commitments:
You are under no obligation until the goods are shipped. You can cancel your order at any time before shipping - free of charge.

Not until shipping:
Your credit card will only be charged once we ship your order. Not before.
Wish List Ask question
40.9 40.9 2 GBP
Description Specification Customers reviews Accessories

SPRINCO USA SPRING KIT-XP BUFFER W/ HD 5-COIL BOLT EXTRACTOR SPRING

40.9 GBP £40.90

Prices inclusive of duty & VAT.

1
2
3
4
5
6
7
8
9
10+
£40.90

Prices inclusive of duty & VAT.

1
2
3
4
5
6
7
8
9
10+

Backorderable, delivery time approx. 4-12 weeks from the USA warehouse.

100-Day Return Policy

Description:

Enhance your M4 Carbine's reliability with the SPRINCO USA Spring Kit.

The M4 CARBINE/6.8 CS SPRING KIT from SPRINCO USA is designed to improve the performance of your M4 carbine. This extra power buffer spring was the first solution developed by Sprinco back in 2006, specifically for a Force Modernization Team addressing spring-related reliability issues in the Eastern Asia Theatre.

Key Features:

  • Increased Load Capacity: The Red spring's design loads are approximately 25% greater than the White spring, ensuring enhanced performance under various conditions.
  • Versatile Compatibility: Commonly used in 9mm, 6.8 SPC, 6.5 Grendel, .450 BM, .450 SOCOM, .500 Beowulf, and Colt LE6920’s specimen carbines.
  • Custom Tuning: Refer to the provided tuning procedure reference documents for recommendations tailored to your specific setup.

Note that some specimen guns may deviate from standard performance due to port values and the power factor of your chosen ammunition loads. Ensure you assess compatibility for optimal results.



Top takeaways

  1. The Sprinco USA Extra Power Buffer Spring is designed to address M4 carbine reliability issues, specifically for challenges faced in the Eastern Asia Theatre.
  2. The Red spring has design loads approximately 25% greater than the White spring, enhancing performance for various calibers including 9mm, 6.8 SPC, and .500 Beowulf.
  3. Before using, refer to the tuning procedure reference documents, as the optimal spring choice may vary based on individual weapon characteristics and ammunition loads.

Attributes

  • Delivery weight: 0.077kg
  • Shipping height: 25mm
  • Shipping width: 25mm
  • Shipping length: 337mm
  • UPC: 657780250066

Item details

Made in USA

Customers reviews

Customer ratings (0)

0 / 5

Variations:

Enhance your M4 carbine's reliability with the SPRINCO USA Extra Power Buffer Spring, designed for optimal performance in various calibers including 6.8 SPC.
M4 CARBINE/6.8 CS SPRING KIT - SPRING KIT-XP BUFFER W/ HD 5-COIL BOLT EXTRACTOR SPRING
40.9 GBP 0 £40.90 *
Backorderable
Product no.: 943000029
Backorderable
40.9 GBP 0 £40.90 *
Enhance your M4 carbine's reliability with the SPRINCO USA Red spring, offering 25% more power for improved function across various calibers.
M4 CARBINE/6.8 CS SPRING KIT - SPRING KIT-XP BUFFER &ENHANCED 4COIL BOLT EXTRACTOR SPRING
40.9 GBP 0 £40.90 *
Backorderable
Product no.: 943000030
Backorderable
40.9 GBP 0 £40.90 *

Customers also bought

Oops! Something went wrong.

We encountered an error while loading this content. Please refresh the page to continue. If the issue persists, contact our customer support.

Site Navigation
Product Categories
Ordering
Customer Service

Welcome!

to Brownells UK, your destination for anything gun related. With our roots in a genuine passion for firearms, we bring you an unmatched selection of Gun Parts, Firearm Accessories, Gunsmithing Tools, Scopes & Red Dot Sights and Expert Knowledge.

Whether you're looking to maintain, repair, or upgrade, we've got what you need!

For Shooters, By Shooters
We share your enthusiasm and know exactly what you're looking for because we're part of the community.

Massive Selection
From the essentials to the unique, find everything under one roof.

Our blend of tradition and innovation
Shop with the convenience of modern technology, backed by a legacy of experience.

Browse our collection and discover why we're the trusted name in shooting sports & hunting.

Brownells Norge - Komplett utvalg av ladeutstyr, våpendeler, kuler, hylser, kikkerter, optikk og luftvåpen Brownells Österreich - Einer der größten Lieferanten für Waffenteile, Büchsenmacherzubehör & Schießsportzubehör Brownells Switzerland - Einer der größten Lieferanten für Waffenteile, Büchsenmacherzubehör & Schießsportzubehör Brownells Deutschland - Einer der größten Lieferanten für Waffenteile, Büchsenmacherzubehör & Schießsportzubehör Brownells France - Le plus grand fournisseur d'Accessoires pour le tir, Pièces détachées & Outils d'Armurier Brownells Iberica - El mayor proveedor de accesorios para el Tiro, Piezas y herramientas del armero. Brownells Sverige - Världens största leverantör av Vapendelar, Vapensmide Verktyg & Skyttetillbehör Brownells Suomi Brownells Italia - Il negozio del più grande rivenditore di componenti e accessori per armi da tiro, difesa e caccia Brownells Polska - Największy na świecie dostawca części broni, narzędzi rusznikarskich & akcesoriów strzeleckich Brownells Česko - Největší světový dodavatel součástí zbraní, střeleckého příslušenství a zbrojního nářadí
*
Prices inclusive of duty & VAT.

© 2025 Brownells UK
Part of the Brownells Europe Group

Logo Brownells
Classical viewClassical view Mobile viewMobile view
Back to top