Polymer AR-15 lower receivers offer light weight, surprisingly high strength and, most importantly, very low cost. Historically they’ve been a bit of a mixed bag in the quality department, mostly due to fit issues caused by molding imperfections. StarLos Firearms has set out to improve on past offerings from other manufacturers by improving the polymer and improving the manufacturing process, and we were happy to put their SLF-15 complete lower through the wringer to see if it worked. 500 rapid-fire rounds? Check. Run it over with my truck? Check . . .
7075-T6 aluminum has had a pretty good run as the materiel of choice for AR lower receivers, but it’s no longer the only game in town. Taking advantage of the lower weight and manufacturing costs of space-age polymers, New Frontier Armory sells an all-polymer AR-15 lower receiver with a price so low ($109 complete) that even cautious shooters are reaching for their wallets and asking themselves, “Why the hell not?” And why the hell not? Your financial exposure is pretty small if a $109 purchase doesn’t work out, but the real question is “Does the damned thing work?” Even the lowest-priced gun has very little value if it’s unsafe or unreliable . . .