Threading help/advice.

[Countryman]

Always worth giving the gunsmith the mod and rifle that want to go together in my experience.

I would now go back to him with both and ask for it to be sorted out.

[R.G.C]

I would expect the thread to be machine cut and checked with a thread ring gauge to confirm it was correct however you could carefully run a split die down it as a last resort. Take your time use a good quality die and use lots of lubricant.

David,
Finding a M18x1 would be a difficult task

MF18x1,5 is the ISO standard.

What is to make sure both threads are same pitch.

Now, cutting threads on a barrel without the part to fit on does not look Professional to me.
R.G.C

[ovenpaa]

I just checked my list and I should have M18x1 and M18x1.5 dies however no gauge for the fine and I do agree with RGC, cutting a thread without the corresponding part is never easy. My concern would be ensuring the part to be fitted to the barrel locked up to the shoulder after running the die down it.

Farmer7 shout if you would like to borrow the M18x1 die.

[farmer7]

I just checked my list and I should have M18x1 and M18x1.5 dies however no gauge for the fine and I do agree with RGC, cutting a thread without the corresponding part is never easy. My concern would be ensuring the part to be fitted to the barrel locked up to the shoulder after running the die down it.

Farmer7 shout if you would like to borrow the M18x1 die.

Thank you very much for the kind offer David, its very generous of you! Before I go for it I have decided to try soaking the threads in Wipe-out and the accelerator to see if it would dissolve any carbon,someone suggested carbon fouling elsewhere. Everytime i remove the mod of the other rifle the oil on the threads is pretty black. Not sure how effective it will be but I'll give it a go.

The mod was used on a factory threaded rifle and measuring across the threads is about 6 thou smaller so wondered if that may have let carbon get down into the threads. Perhaps the new one is cut perfectly and the factory one is undersize?? Its certainly spins on very freely on the old rifle.