If you’re looking to boost your fps these will do just that! They are best used with 13mm springs or 9mm spring guides. (You’ll need the spring guide sleeve if you get the Springer Custom 7mm spring guide). There’s 3 separate rings one at 2mm, 4mm, and 6mm sizing. Each increasing the fps at different rates. They are made of steel and black oxide coating, to make it last as long as possible with great durability! Usable in a variety of bolt action platforms.
