The are all destined to be slightly unique determined by Resource don And just how persons are measuring them. Changing the buffer spring with a standard carbine spring (minus 3 coils), and also the buffer that has a eleven.5oz AR stoner 1 looked as if it would fix the issue https://zanepcsgw.bloggazza.com/33704653/the-best-side-of-rare-breed-trigger-3-position-upgrade