Built by builders. Cut to spec.
I’m Jake Morrison. Before AR-15 Lower Lab, I spent fourteen years machining aerospace parts in Mesa — the kind of work where a half-thousandth tolerance gets a part scrapped and a thousandth gets a contract canceled. When I started shooting NRA High Power in 2016, I started buying lowers, and I started noticing how many of them came out of factories that wouldn’t pass an aerospace audit.
Most rifles fail at the lower. Not the upper, not the trigger group — the lower. A lower that’s out of spec on the buffer tube threads, on the takedown pin holes, on the trigger pocket depth, will give you a rifle that almost works. Almost is the worst place a rifle can be.
What we do differently
- 7075-T6 forged aluminum. Stronger than 6061. We don’t use 6061. Some sellers do because it’s $40 cheaper per receiver — they don’t tell you that.
- Type III hard-coat anodizing. 0.0020″–0.0025″ thickness. Tested per MIL-A-8625 in our Phoenix shop.
- +/-0.0005″ tolerance on critical dimensions. Trigger pocket, hammer pocket, FCG holes, takedown pin holes. Each batch is gauged. We keep the QC sheets.
- FFL transfer included. We hold the receivers at our Arizona FFL until your dealer’s transfer paperwork is in. No drop-shipped surprises.
The shop
AR-15 Lower Lab runs out of a 2,800 sq ft industrial unit off Buckeye Road in Phoenix. Two 4-axis CNC machines, one 5-axis for billet work, a Brown & Sharpe CMM for tolerance verification, and a small anodizing line. We run about 280 receivers a month. Most of them ship within five business days; billet work takes ten to fourteen.
If you want to talk specs, call the shop direct: (602) 555-0188. We’re open weekdays 9–5 Mountain Time. If you reach voicemail it’s because we’re at the machines.
What we don’t do
We don’t sell completed rifles. We don’t sell uppers. We don’t sell triggers, BCGs, handguards, or anything other than lowers, billet receivers, and 80% lowers. There are plenty of good shops for the rest of the rifle. This shop is the lower.
— Jake