One day last summer, a friend introduced me to his new AR-15 semiautomatic rifle. I’ve had a relatively casual interest in firearms over the years, owning a few of my own. I’d even worked in the firearms industry (no mean feat when you live in San Francisco) where I handled practically every gun built by man. I played with the rifle and shot it a few times, but didn’t take to it right away.

But the seed was planted, and slowly my opinion changed. The more I looked into the AR platform, and discovered what it was like, the more I wanted one. It seemed like something I could turn into a hobby, and I was looking for a new hobby.

So I built one. It was surprisingly easy and a lot of fun.

The AR in AR-15 stands for “Armalite Rifle,” the granddaddy of the M-16 and the rifle that started it all. Today the term stands for the civilian version of the Army and Marine Corps’ M-16. The AR-15 has been in the news recently for two reasons: one, it’s incredibly popular, with something approaching five million rifles in circulation. Second, it’s been used in several recent high profile mass shootings, including Aurora, Colorado and Newton, Connecticut.

AR-15 owning is the perfect storm of modern red-blooded American male instinct: it combines shopping, owning, Internet viewing, building, beer drinking, occasional swearing, shooting and tinkering. Endless tinkering; the AR-15 has been called the “Barbie Doll for men.” Like Barbie and her outfits, toy cars, swimming pools and houses, the AR-15 is endlessly interchangeable with a vast array of accessories. Almost every part of the rifle can be installed and uninstalled and replaced. A rifle built for target practice can be transformed into a rifle for hunting — or close-quarters battle — in a matter of minutes.

Ordinary people with little or no gunsmithing experience can build a rifle in about half a day. There is no instruction manual; aside from a few tools, the most important thing you need is YouTube. Everything you would want to know about building an AR you can watch on YouTube, courtesy other AR enthusiasts. It’s a very helpful crowd.

The first thing I needed was a stripped lower receiver. I purchased one locally, made by Smith & Wesson. The lower is actually just a brick of shaped aluminum that holds the trigger, hammer, and safety. You might compare it to the handlebars of a bicycle, something fairly nondescript but which you absolutely need if you want to build a bicycle. It doesn’t even look like a firearm, but legally it is, and it’s the only part that I needed to submit to a background check and go through California’s 10-day waiting period for.

Like a bicycle, the other 90 percent of the rifle can be ordered by anyone from hundreds of different manufacturers and vendors, and I spent hours window shopping parts online. The parts can then be mailed directly to your home address. Since all parts are produced to a common military specification, you could buy parts from a dozen different manufacturers and they will fit together correctly. This made for lots of incoming packages.

If you want to build something American-made — and I mean out of parts 100-percent manufactured in the USA and not merely assembled here — build an AR-15. My rifle is entirely American, from the cold hammer forged steel barrel to the machined aluminum hand guard to the smallest pins holding it together, all made in places like Wisconsin, North and South Carolina and Colorado. I didn’t even have to try to make it all-American, it just happened that way. China doesn’t even enter the picture, due to laws limiting the use of imported parts. I have a hard time thinking of anything else you can build entirely out of American parts.

Kyle Mizokami photo

One day the last of my orders came in the mail — the parts kit and gun stock. I had planned on building the rifle that weekend, when I had set up a workstation and watched the same instruction videos on YouTube a dozen times each. The weekend was still a few days away, but the anticipation was killing me. I sat at my desk, cleared a little room and decided I would build until I got into trouble and had to stop.

I improvised. Instead of a vise and a workbench I balanced my lower receiver on a couple of books and my mouse pad with kittens on it. I had bought some tools, a set of punches and a brass hammer, but was able to wing the rest. Like any self-respecting man I had my own screwdrivers. I went running to the kitchen for a chopstick. Instead of buying the $18 specialized tool to install the hand guard, I used my wife’s canning tongs.

I fully expected to hit a brick wall, but I never did. After four hours, I had a complete rifle.

At the end of the build I slid the two halves of the rifle together. Despite my fears that it would, at the minimum look lopsided or somehow appear obviously wrong, the parts fit perfectly. I performed a functions check, pulling back the bolt, inserting an empty magazine, slamming the bolt forward, and squeezing the trigger. The mechanism — which I had built — worked flawlessly. I jacked back the charging handle and the dummy bullet I had loaded went flying out of the chamber and hit a wall next to me.

A month after I had finished the rifle, I took it up to a friend’s cabin up near the Oregon border. I loaded a magazine with 5.56-millimeter bullets, took aim at an empty bottle of Coca-Cola, and pulled the trigger. The rifle went bang.

I had built my own rifle. And you can, too.

Kyle Mizokami photo