Mil-Spec Lower Parts Kits Dirty Birds Gun & Ammo is excited to offer these high-quality Mil-Spec Lower Parts Kits at wholesale prices. We source these in large batches from the same companies that supply our military and top rifle manufacturers in the industry. Given that we are purchasing surplus in large batches, we can’t guarantee to keep them in stock at all times, so be sure to stock up on them as they become available. Buy Mil-Spec Lower Parts Kits with confidence. Packaging may vary, but each kit is backed by our Satisfaction Guarantee. Backed by NBS Limited Lifetime Warranty