SPRINCO USA Spring Kit – XP Buffer Spring & Enhanced 4Coil Bolt Extractor Spring
Enhance your AR’s reliability with the SPRINCO USA Spring Kit, featuring:
- Extra Power Buffer Spring (Red)
- Enhanced 4Coil Bolt Extractor Spring
Originally designed in 2006 for a Force Modernization Team, this kit addresses M4 carbine reliability issues in challenging environments. The Red spring offers approximately 25% greater design loads compared to the White spring, making it ideal for:
- 9mm, 6.8 SPC, 6.5 Grendel
- .450 BM, .450 SOCOM, .500 Beowulf
- Colt LE6920 specimen carbines
Note: Performance may vary depending on port values and ammunition loads. Consult tuning procedure documents before use.






