This enhanced disconnector spring for improved function with some Sig MPX and 9mm AR platform variants.
We have found that some firearms have tolerances outside of the mil-spec tolerances the BFSIII™ is designed for. This spring can help in some but not all of those applications.
Please contact customer service if you are unsure if you need this spring.
The enhanced spring is recommended to be replaced at a service interval of 1000rnds some firearms may need replacement sooner.
These enhanced springs are sold in packs of 5.
BFSIII™ is NOT for civilian sales in CA, CT, DC, DE, FL, HI, IA, MD, NJ, NY, RI, and WA