Sprinco USA 308 M4 Extension Tube Cs Xp Buffer Spring in Hard Tube
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Spro USA
Overview
The Sprinco USA 308 M4 Extension Tube CS XP Buffer Spring is specifically designed for AR-10 platforms, featuring a carbine length that optimizes cycling performance for your build. With its XP power rating, this buffer spring provides enhanced resistance to compression, ensuring reliable operation even under demanding conditions. This spring is commonly found in builds with a mid-length gas system and is often paired with the 5.56 NATO caliber, making it a versatile choice for those looking to enhance their firearm's reliability and functionality.
Specifications
August 2026 on GunPartPicker
Spro USA Sprinco USA 308 M4 Extension Tube Cs Xp Buffer Spring in Hard Tube was the ninth most added buffer spring on GunPartPicker in August 2026. Builders have been adding it to their builds on GunPartPicker since February 2026. All time, it is the tenth most added buffer spring on the site. Builds with this buffer spring are mostly chambered in .223 Wylde (63%, then 5.56 NATO 38%), split between mid-length (40%) and pistol-length (20%) gas systems, and mostly AR-15 (78%, then AR-10 11%).
Availability is good: it was in stock at one retailer or another nearly every day in August 2026, and today 6 of the 7 retailers we track have it in stock. The best price crept up from $18.96 to $19.95 over August 2026. Buying today, the lowest price is $19.95 at Primary Arms, above August's low of $18.96, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 31 retailers
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Read the guide: AR-15 Buffer Spring Guide →Frequently Built With
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Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
PlatformBased on real build data showing which platform (AR-15, AR-10, AR-9) builders pair with this product.
CaliberBased on real build data showing which calibers builders choose alongside this product.
Gas SystemBased on real build data showing which gas system lengths builders use with this product.
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