Machining an AR-15 Barrel from a Blank

I am not a machinist, but that does not preclude me from appreciating their work and the skills required to create weapon systems. To further my appreciation, has posted up an excellent pictorial tutorial on machining your own AR-15/M16 barrel from a blank. 

Cutting the target crown.

Cutting the target crown.


There are a few specialized parts (not to mention knowledge) required, but in the end they have an excellent barrel after only “a few hours on the lathe.” Assuming you have the machines or easy access to a machine shop, the parts and tools used for this tutorial come out to about $500. The blanks themselves are only about $160. 



Final product next to a section of blank.


TFB machinists: did the tutorial miss anything or did they cover everything?

Nathan S

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

The above post is my opinion and does not reflect the views of any company or organization.


  • Wes

    That’s not exactly the order I would have done things in, but that’s about right.

  • Eric S

    I’m always a bit disappointed in these ‘how to’ guides as you have to have an existing knowledge to make use of it. For once I’d like to see one that talks about RPMs, angle of the bit, HSS vs carbide, feed rate, etc.. As I have a cheap 9mm blank I want to turn down for a Sten build, but I have no formal knowledge, but I guess this is a start.

    • Not sure if that level of detail could be considered “how to.” With that level of detail required you need a video or a full manual!

    • dan citizen

      Step 1: rough out your billet on your abrasive water jet
      Step 2: trim it up with a plasma cutter
      step 3: bore your holes with your EDM
      step 4: finish up on your 4 axis CNC



      Eric S: I’m the author of the article. I normally don’t comment on forums or comment boards, however, you raise some valid points.

      Nathan is correct in his post below, things get entirely too long if you break everything down too much. What I try to do is focus on different methods and techniques, highlighting a specific area in each article. For instance, I probably have 12 different write ups chambering barrels on the site, some are dialed in the ends, some on the chamber end, some are turned between centers, some focus on heading spacing.

      You’ll notice the HSS tools listed in the top of the articles. On most smaller machines, the HSS tools give you an excellent finish on stainless barrels. I normally turn my barrel around 400 RPM, thread around 220 RPM, and chamber at 70 RPM. Tooling set up and angles are covered in other areas of the site. My compound 29.5 degrees.

      Practical Machinist, Snipershide Gunsmithing and Accurate Shooter (6mmBR) all have excellent gunsmithing forums with guys willing to help if you have specific questions.

      Bill: You are correct. One of my proof readers is a special agent that works for one of agencies that would be responsible for prosecuting something liked that. I called him and mentioned the comment just now, he laughed and suggested I get out my tin foil hat.

      Nathan S. Thank you for posting a link to my article.


      • We always want to make sure the author gets credit!

      • Eric S

        Thanks for the follow up. It’s just that I see ‘how to’ like this and I’m reminded of auto shows or this old house where they have thousands of dollars in tools and decades of experience that are fun to watch and difficult to replicate.

    • iksnilol

      You could probably take classes, do machinists do that? I have a friend who is one, he helps me out, might even teach me something.

      • Eric S

        No classes offered in the county unless I went to work for Boeing.

  • lucusloc

    That’s a nice short blank you got there, be a shame if you got caught for constructive intent. . .

    • The Hun

      “constructive intent” – sounds like a “Minority Report” term.

      • gunslinger

        thought crime!
        is the ministry around?

    • Bill

      That’s the most foolish thing I’ve ever heard. Smiths have had been cutting off blanks for decades and no one has ever even suggested that nor has anyone been prosecuted. Where do you think pistol barrels come from? I’d imagine most rifle owners also own a sawza as well.

    • JaxD

      That’s a nice (piece of pipe) you got there, be a shame if you got caught for constructive intent.
      Ha ha ha.

    • Texas-Roll-Over

      haha god you’re dumb.

    • jim

      Another “Ahhh!” Constructive Intent internet policeman. Good thing constructive intent doesn’t exist… It’s constructive possession and its extremely rarely prosecuted and then only as an add on charge. Go find some one else to troll.

  • iksnilol

    Why turn it down? Keep it as is to get a bull barrel.

  • opie7afe

    blanks for 160, are you nuts? use green mountain and can get one for much much cheaper and they are quality barrels…..i dont know why so many gunsmiths use brownells for certain things..certain things brownells is way over priced….i got two 15.5″ blanks for under 70$ shipped from green mountain….smh…

  • BlueBuddha

    What I learned from this little tutorial is that I need to stock up on some barrels, because there’s not a chance in hell I’ll ever be able to turn one myself.