By entering your mobile number above, you consent to receive Rainier Arms back-in-stock text notifications from 35657 to that number. Msg frequency may vary. Msg & data rates may apply. Reply HELP for help and STOP to cancel. See Terms and Conditions & Privacy Policy
Introducing a cloned upper receiver build of the MK12 SPR. Bringing the highest quality parts to the market, while offering the best value as well. This partial upper build utilizes a Precision Reflex GEN III free float handguard and front sight. Pairing up with our forged upper receiver and Ultramatch MOD 2 SPR 18" barrel. Throw in your favorite charging handle and bolt carrier group and you are good to go!
Review by Mike T. on 29 Mar 2023review stating Excellent upper
I purchased this wanting a MK12 style upper. The quality is excellent and accuracy is on par with what I would expect. With 77 gr OTM I am getting a little better than 3/4 MOA and was able to hit steel out to 720 yards. Extremely pleased with this upper.
Review by Steve on 19 Feb 2023review stating Extremely Accurate
Excellent is all I can say. Because of their barrel making process Rainier CS said I didn't have to break in the barrel. They were right. Extremely accurate out of the box. Everything is excellent quality.
Review by Mike T. on 29 Mar 2023review stating Excellent upper
I purchased this wanting a MK12 style upper. The quality is excellent and accuracy is on par with what I would expect. With 77 gr OTM I am getting a little better than 3/4 MOA and was able to hit steel out to 720 yards. Extremely pleased with this upper.
Review by Steve on 19 Feb 2023review stating Extremely Accurate
Excellent is all I can say. Because of their barrel making process Rainier CS said I didn't have to break in the barrel. They were right. Extremely accurate out of the box. Everything is excellent quality.
