Threading a barrel - Bushmaster HBAR flat top upper

[ripcurlksm]

Can I thread the barrel to add a flash suppressor if the barrel doesn't already have it?

[Seesm]

One with or without EVIL features?

[ripcurlksm]

it has a bullet button... I suppose the question is not am I allowed, but can I modify a barrel without threading... a gun smith I figure

[CHS]

Yes. Perfectly legal. A "flash hider" added afterwards counts as a feature, but barrel threading IS NOT a feature in and of itself.

[ripcurlksm]

ok I will rephrase-- how hard is it to rethread a barrel and can most gunsmiths handle this?

[CHS]

Not hard, and yes.

[kingjoey]

ok I will rephrase-- how hard is it to rethread a barrel and can most gunsmiths handle this?

Pretty easy, we do probably 20 each week

[ripcurlksm]

Randall did an AWESOME JOB from ar15barrels.com -- I drove up to LA, he did a pro job threading my barrel and is a nice guy.

[Asphodel]

Ripcurl,

The basic answer is, yes, you can thread a barrel, and its a relatively easy job.

That said, there is a bit of 'learning curve' involved in making a proper job of that work.

Assuming you have or will be getting a good lathe, the South Bend basic lathe book 'How to run a lathe' will explain the technique of single-pointing a thread. The old LeBlond book 'Running a Regal' might be worthwhile, as well, and there may well be some other useful books you could find.

A copy of 'Machinery's Handbook' will give you all the data on many 'special' threads, including tolerances for the grade of thread you wish to cut.

Invest in a good thread pitch mic. for the dia/pitches you will wish to cut, and in practicing grinding/honing a tool bit to an accurate 60 deg.

Then, 'practice makes perfect'.....try threading a few scrap barrels, to 'get the feel' of the job. Once you have done a few, you'll find accurate thread cutting work to be simple and easy.

I prefer a mixture of 1 part black cutting oil, and 1 part 'Rapid-Tap', or equivalent, tapping oil for this work. Be certain to keep oil on the cut and never let it 'go dry', as you'll lose the edge of your tool bit in 'an instant' should it go dry.

When trying the gage or mating part on a thread, be certain the workpiece is cooled to ambient. If you take ''just another .001' cut til the gage fits nicely with the workpiece warm, the thread will be just that little bit loose when the part cools. Likewise, brush the new thread really clean before trying the gage or mating part. A very tiny chip can 'lock up' a gage on the work.

On edit: Barrels are not necessarily concentric, that is, the bore may run out several thou from the o.d. Arrange suitable fixturing, and dial in the barrel using a gage pin in the bore.

The above assumes that you are willing to make the investment in time, tooling, and energy to learn to thread barrels correctly......if you were asking primarily from curiosity, or wondering about amateur work, trying to thread with a die (don't even try that), then just send the barrel to someone who regularly does this work. (but don't ask me.....I get to be 'retired' these days)

cheers

Carla

[ripcurlksm]

thanks Asphodel! And welcome to CalGuns!