Product Description Phase 5 Weapon Systems LOPROGAS Lo-Pro Gas Block Mag Phosphate 4140 Chromoly Steel Phase 5 Weapon Systems LOPROGAS Lo-Pro Gas Block Mag Phosphate 4140 Chromoly Steel at Shooting Surplus Browse all Shooting Surplus deals $31.60 In Stock at Shooting Surplus Price checked 4 days ago Buy Now at Shooting Surplus Secure checkout Easy returns or compare prices Amazon eBay Product Details Brand Phase 5 Phase 5