Introducing the RUC PRO MK1 Partial Upper. Bringing the highest quality parts to the market, while offering the best value as well. This partial upper utilizes a Rainier Arms Low Pro nonadjustable gas block on our new and improved Rainier Arms Select barrel. Pairing up with new PRO series MK1 handguard to provide shooters with a rock solid handguard that can take any abuse. Throw in your favorite charging handle and bolt carrier group and you are good to go!

10.5" Upper:

• Rainier Arms Select 5.56 NATO Barrel - 10.5"
• Rainier Arms Forged Upper Receiver
• Rainier Industries PRO Series MK1 Handguard - 9.55"
• Rainier Arms Low Pro Gas Block - .750" (Non-adjustable)
• Rainier Industries .223/5.56 Flash Hider - 1/2x28
• Carbine Gas Length
• Weight: 2 lbs 14 oz

11.5" Upper:

• Rainier Arms Select 5.56 NATO Barrel - 12.5"
• Rainier Arms Forged Upper Receiver
• Rainier Industries PRO Series MK1 Handguard - 11.7"
• Rainier Arms Low Pro Gas Block - .750" (Non-adjustable)
• Rainier Industries .223/5.56 Flash Hider - 1/2x28
• Weight: 3 lbs 2.6 oz

12.5" Upper:

• Rainier Arms Select 5.56 NATO Barrel - 12.5"
• Rainier Arms Forged Upper Receiver
• Rainier Industries PRO Series MK1 Handguard - 11.7"
• Rainier Arms Low Pro Gas Block - .750" (Non-adjustable)
• Rainier Industries .223/5.56 Flash Hider - 1/2x28
• Weight: 3 lbs 2.6 oz

14.5" Upper:

• Rainier Arms Select 5.56 NATO Barrel - 14.5"
• Rainier Arms Forged Upper Receiver
• Rainier Industries PRO Series MK1 Handguard - 13.7"
• Rainier Arms Low Pro Gas Block - .750" (Non-adjustable)
• Rainier Industries .223/5.56 Flash Hider - 1/2x28
• Weight: 3 lbs 8.4 oz

16" Upper:

• Rainier Arms Select 5.56 NATO Barrel - 16"
• Rainier Arms Forged Upper Receiver
• Rainier Industries PRO Series MK1 Handguard - 15"
• Rainier Arms Low Pro Gas Block - .750" (Non-adjustable)
• Rainier Industries .223/5.56 Flash Hider - 1/2x28
• Weight: 3 lbs 12.6 oz

Please NOTE: BCG and Charging Handle NOT Included.