Adams Arms Drop-In Piston Conversion Kits For AR-15 Mid Length
Contains our 1 piece bolt carrier, handguards and handguard cap. The Adams Arms Gas Piston System is an end user installed after-market product for Mil-Spec ARs.
It will fit on any AR barrel with a .750" or 3/4" diameter at the shoulder where the front sight base sits. The Midlength version will work on barrel lengths from 16" to 18" that has an existing midlength gas system. See the FAQ section for the measurements of a midlength gas system.