rail system fitting issue

[alex90]

I have started an m4 build and got myself a g&p zombie killer reciver and a second hand rail system of facebook selling site it the style with the big metal donut with loads of hole in and a larger nut to lock it all in not delta nut style

And iv tryed dry fitting eveything and the metal donut is not screwing on to the body nicly and all the threads look fine and iv took some 800grit paper to take some of the paint of but still not going on properly

Any ideas why

 

[Silentassasin]

can you post a picture??

 

[alex90]

The only thing I can think of is im doing it wrong haha but yeah give me 20mins other half on laptop

 

[alex90]

hear u go

View attachment 9820

 

[Mack]

Most likely the barrel nut is Metric and the G&P threads are Imperial. You would have to rethread the receiver or find the same barrel nut with Imperial threading.

 

[alex90]

Balls I was hoping that wasnt the case but get my old.man to make one up

Or do u now wear sells them in there own as I love that lave system and done some custom work to it shortining the outer barrelnand stuff

 

[jcheeseright]

 

[alex90]

Any idea what the thread size is on the reciver