Home Forums Hunting & Shooting Gunsmithing threading question

Gents,

Some of you know from a post in the hunting rifle forum that I've been working on a M70 XTR that came to me with mystery threading. I *thought* that I had things figured out when a 14x1RH nut screwed right onto the threading and ordered a 14x1RH thread protector... that doesn't fit. Seems too small. What am I missing here?

Thanks y'all.

Maybe you were sent a 1/2-28 thread protector by mistake.

Have you used a thread pitch gauge to check the barrel threads? There's more to threads than number and pitch...thread depth on both pieces is a biggie.

If the thread protector is coated, it might need the threads touched up a smidge. I ran into this not long ago with a suppressor on a friend's rifle.

Hope this helps. -Al

Good point, Al. I forgot. I had this same problem once too. It may just need a tap run through it to clean the threads.

A cheap Chinese tap from Amazon or Ebay will get the job done. I wouldn't trust them for production work though.

https://www.amazon.com/Pitch-Thread-Metric-Right-Useful/dp/B075J7CHY1

I see a number of Winchesters coming back from Europe with threaded barrels. I'm not a.supressor guy so never tried to fit one on these but .maybe they are metric.threads..

Metric to us treading adaptors are available silencer central as a.big.selectiomln.

There's an idea. Maybe you can get a SAE thread adapter and put a thread protector over the adapter over the muzzle threads. I bet it would all blend in perfectly.

SAE and Metric thread pitch gauges are available at most any decent hardware or fastener store...right by the taps/dies. Any decent tap/die set will have one included. Or you can pour a cup of coffee and have a Performance Tool W8655 from Amazon tomorrow.

Until you know the thread on the barrel, everything is just guessing. Once you know that, there's only a couple things that can be wonky.

Thread pitch gauge is on the way.