CNC machined from solid billet 7075-T6 aluminum which is 70% stronger than the commonly used 6061 aluminum and finished with milspec hardcoat anodize to a surface hardness of 60 Rockwell. Renewed design to work with 99.9% of all accessories, including; the Magpul BAD lever, Daniel Defense Lite rails and even features the pre-drilled alignment hole for the Noveske NSR Rail. If you want to build the best upper money can buy, look no further than the Rainier Arms UltraMatch Billet Upper. Extremely robust yet weighs in at a mere 9.3 oz. Made in the USA.
- Life Time Warranty against defects & workmanship
- 90 day - Satisfaction guarantee - 100% money back with no questions asked
The most critical features are:
- Parallelism between the picatinny rail, main center bore and the centerline of the mounting lugs
- Perpendicularity between the centerline of the lugs and the barrel mating face (at the front of the threads)
- Flatness of the barrel mating face
Rainier Arms is holding .0003 or better on all of those measurements. Competitor uppers are between .001 and .003 on the perpendicularity and parallelism.