Samson Manufacturing Corp. AC-556 Style Gas Block Front Rifle Sight Fits Mini 14 Manufactured in 2007 and Earlier Stainless Steel Finish Silver. 2008 or later in Black or Stainless are compatible with Mini-14 rifles with a factory flanged .625" diameter barrel manufactured in 2008 or later with a serial number prefix of 508 or higher. Additionally Mini Thirty 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-14 rifles with a factory straight pencil .562" diameter barrel manufactured in 2007 or earlier with a serial number prefix of 181 through 199 but not including 580 or higher. Specifications for Samson AC-556 Style Gas Block Front Rifle Sight: Manufacturer: Samson Fabric/Material: Stainless Steel Gun Make: Ruger Gun Type: Rifle Package Contents: XS Sight Systems R3D Tritium Pistol Night Sights What firearm models does the manufacturer say Samson AC-556 Style Gas Block Front Rifle Sight is compatible with? The manufacturer suggests that Samson AC-556 Style Gas Block Front Rifle Sight is compatible with Ruger Mini-14 Post 2008 Ruger Mini-14 Pre 2008