Rem 870 tube thread

[michaelsabre]

Hi Knowledgeable GNZs,

Any one know what the thread size of Rem 870 tube? Basically the thread of this part:

Thanks!

Michael

 

[farmer47]

i believe it is acme thread.our shop guages are of no help because of the thread design .i too am interested to figure out what the thread is and will continue to ask until i get a proper answer.

 

[rapidfire]

I just had a machinist friend thread an extension tube and he said he had to create a special cutting tool to do it. Quite an unusual thread he told me...

 

[PerversPépère]

The Japanese makers of the S&W3000 police shotgun (I think it was Howa Gunworks) avoided that peculiar thread for their 870-inspired creation by using a finer thread with a different pitch and longer engagement surface.
Only problem: none of the current market magazine extenders intended for the 870 can fit.
I guess I'll have to ask Casey Brouwer to make one for me using the original S&W barrel nut...
PP. $$