Lathe-less Barrel Threading

Iraqveteran8888 put up a video of Ryan threading a Mosin Nagant barrel using a power drill and a special bit that is cutting the shoulder.


The bit has a pilot guide rod that helps keep the bit centered on the barrel. After cutting the shoulder Ryan can thread the barrel using a die.


Looks simple and easy. Just not sure what the guide rod is doing to the rifling inside the barrel. If the fit is perfect then the threading will be concentric. However the tighter the fit of the guide rod, the more it will rub on the rifling. If it is loose, then the rifling might not be damaged but then the threading won’t be concentric. I suppose it depends on what the pilote guide rod is made of.


And here is the fruits of his labor. It is so quiet.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at


  • iksnilol


    I don’t have sound at the moment, so I couldn’t really listen.

    • Xtorin O’hern

      he loads 205 grain subs and 120 gain supers for that gun

  • Tritro29

    OK now please put some range data (ER/MV etc) I’m about to make a business proposal. Divorce is about to get far less expensive.

  • BryanS

    A brass guise rod would probably not hurt the rifling, or a delrin coated steel one. Im more interested how it threads at that revolution, and where I can get a set of them.

    • Vhyrus

      That tool is not cutting threads, it is only cutting a shoulder that can then be used to setup a die to cut the actual threads.

  • Phillip Cooper

    Tapping threads with a die really isn’t anything groundbreaking.

    This is neat, but nothing innovative. As for the guide rod and damage to the rifling- non issue assuming the guide rod is not a harder material than the barrel’s rifling, and/or precisely machined. A greater concern would be setting off an explosion behind a piece of copper and lead stripping out the rifling- and that works pretty well.

    • BryanS

      Ive never seen a die like that. You have any info on it?

    • nova3930

      That was my thought. Even when threading on a lathe, anything going in the bore should be brass or similar. I’m not yet confident in my abilities to try it but I’ve been working on a setup with brass chamber and muzzle inserts to thread barrels for my SIG 320….

  • Nathanusername

    The drill attachment doesn’t do acting except cut a shoulder the correct diameter to then thread by hand with a die. If the mosin somehow came in the proper diameter for threading, the drill wouldn’t be necessary. Interesting tool though.

  • the Other cliff

    The key here is concentricity. The reason you cannot just thread the end of a barrel is that the bore is seldom exactly centered. This gizmo turns a shoulder and makes an outside diameter of the right size for threading that is perfectly concentric with the bore. At that point, a simple die will thread the barrel.

    • JumpIf NotZero

      perfectly concentric with the bore

      Hobbyist machinist here… I’ll take that bet. Good enough for a mosin, sure.

      • BrandonAKsALot

        I’m going to agree here. Sure it’s concentric if you’re measuring in tenths of an inch, but just because it has an alignment pilot, doesn’t make it concentric. Bore tolerances vary and so will the pilot and that can lead to a nasty tolerance stack if you are threading something needing precision.

        A dial indicator will quickly show what kind of precision it’ll bring. It’s good enough for some applications, but not for everything.

  • SCW

    That’s an annular cutter. Just in case anyone out there was curious. They are usually used for quickly cutting round holes in thick material. It’s faster b/c you’re only cutting a small ring of material. There will be a slug of material left after the cut is complete. With a drill bit you’re cutting the entire diameter of the hole. Annular cutters also cut a more accurately sized hole than a drill bit.

  • Mr.Volt

    I feel inexpressebly Metal Gear Solidish about it.

  • Mymossgunsmith

    If you guys are worried at TFB we could send you a barrel we’ve threaded and inspect it. Just to see what you thing…

  • Bill

    Gunsmiths love Dremel tools and stuff like this. Homedone mods and “repairs” give them a steady revenue stream, undoing the damage.

  • Dave Bryar

    A 10″ barreled Mosin SBR with a silencer…. YES, I want to hear more about this project

  • BryanS

    Cool, thanks for the info!

    I can run a mill, but in no way am I skilled at it.