This is truly a one-of-a-kind build. Featuring the Bear
Creak Arsenal’s patented right-side charging upper, Adams Arms carbine piston
kit, and Frog Arms custom lower.
This build required carbide bits to drill and tap the holes in the side of the Adams Arms bolt carrier using a template based on the Bear Creek direct-impingement bolt carrier. This transformed the Adams Arms bolt carrier into a right-side charging bolt carrier for this custom upper.
Adams Arms piston is installed with their 15-inch M-Lok rail
and barrel nut (the Adams Arms piston does not work with the Bear Creek barrel
nut). In defense of Adams Arms, their piston kits were originally designed for mil-spec
barrel nuts. Adams Arms are great pistons and I have a couple in my personal
collection. Compatibility with more manufacturers’ barrel nuts is one of the
reasons Frog Arms is now using Superlative Arms piston Kits.