Indians For Guns

I would like to know what is external diameter of Precihole NX100 Polaris (0.177) bore diameter at the muzzle. I would be very grateful if some owner could measure it (it's a little less than muzzle weight mount diameter). Or maybe it's described in some documentation? Thanks in advance!

This is the dimension I need to know

I would be extremely grateful if someone could measure it.

Assuming muzzle external diameter is the same for different calibres, mine measures 15 mm.
I see you have a lot of different queries about precihole NPs, why don't you contact precihole directly and get all your doubts cleared?
http://www.preciholesports.com/contact.html