Strike industries ar carbine flat wire spring - Strike Industries AR Carbine Flat Wire Spring

I initially purchased this flat wire spring for an AR9 SBR build. I was trying it for the "blowback9" gentle recoil system. Its ID is too small and binds on the hydraulic buffer. I put it in a standard buffer system, and it works as advertised. So, if you are trying to get the flat wire buffer spring for the GRS this will not work. Also, it is more difficult to install and remove from buffer tube. It does not slip over the buffer retaining pin like a round wire spring.