Veteran barrel and shroud questions

Much appreciated. 

Interesting that mine seems to be built a little differently. 

Here's a look down the shroud with all the baffles removed. 



Rotating the shroud tube allows everything to spin EXCEPT the collar with the nine holes seen at the bottom of the shroud here (kinda looks like a magazine). 

In the upper right you can see what looks like a split ring right behind the 9 hole bushing. The split ring behind the 9hole bushing turns while rotating the shroud body but no unthreading is occuring. I think that nine hole bushing has got to come off before the shroud will......... but it's not budging. Thinking maybe some welding rod placed in two of those holes at 180 degrees (kinda like the hammer tension adjuster) might allow me to get enough torque? 

Or am I completely off base here? Any other ideas as to what I'm dealing with?

Come to think of it, I think the shroud would slide all the way off the back end of the barrel, leaving that 9 hole bushing in place on the end of the barrel, IF I removed the barrel from the gun. 



Shroud slides backwards quite freely, until it hits the scope mount pillar. 

Success!

..........perhaps overtightened in production.....screw driver or dowel, engage it in one of the holes, and it should loosen........ This is a good example of why you can't assume that things are properly assembled.

Click to expand...

Screwdriver trick worked, but it was just about all I could do to get it to loosen with just my hands. Since I'd never had it off, just came from the factory really torqued down. 

Took some pics while I was there in case somebody stumbles upon this thread in the future....

As Intensity states, 1/2-20 threads....



Expanded baffle arrangement.



All the baffles sit in front of that lock ring.



Compressed baffle arrangement, and yes, there's about 2 inches of dead space behind that lock ring.



That two inches of dead space I didn't know about makes the barrel in this Short about two inches longer than I figured it was, so 13.75inches.



When measured from this point, assuming that's about how deep the threads at the breech end go.



This all allowed me to do the first really good cleaning job the barrel has ever seen. I think I'm about 12 tins through this gun, with only a few patches pulled through here and there, without ever seeing any degradation in accuracy. Gun was purchased new by me. 

Also got some close ups of the crown and rifling. 

12 land and groove and this gun is authentic CZ era barrel, pre Utah Airguns involvement. 



Crown is a little rougher than I expected, but the gun shoots, and always has, exceptionally accurately. Can't argue with results, rough crown or no. 



Thanks for the help guys. 

(Reassembled with normal shroud/moderator torque and it threads off and on like it should now, screwdriver song and dance no longer necessary).