Upgrade your factory gas block with their original B.A. Sling Point gas block cap designed for the RugerA(R) Mini-14A(R) and Mini ThirtyA(R) 2008 or later in Black or Stainless are compatible with Mini-14A(R) rifles with a factory flanged .625"" diameter barrel manufactured in 2008 or later, with a serial number prefix of 508 or higher. Additionally, Mini ThirtyA(R) rifles with the older factory straight pencil .625"" diameter barrel and the new factory flanged .625"" diameter barrel will be compatible. 2007 or earlier in Black or Stainless are compatible with Mini-14A(R) rifles with a factory straight pencil .562"" diameter barrel m Mfg: Samson Manufacturing Corp