I have had this ASC Bologna Extra for about a year, and was always curious about how to disassemble it because one day I will have to re-sac it. Today, with a thought derived from another thread on FPN, I was feeling brave and did it.
First of all, I would like to thank FPN member sannidh and Youtuber sbrebrown for their answer and video to help me with this disassembly. sannidh's original post is here (a different topic but indirectly related to this because of the same filling mechanism): http://www.fountainp...rosewood/page-1
sbrebrown's video relevant to disassembly of this model is: Please see minute 4:44.
Please see below photos: You can unscrew the nib/feed unit out of the section. You can unscrew the section out of the barrel.
1. There was no shellac or other heat sensitive adhesive on plastic nib collar threads so unscrewing was rather easy, both the nib unit and the section.
2. The nipple size seems to be for size 22 sac (or one size bigger or smaller), but the sac seems thinner in diameter. I could be wrong but it looks at least in my case, the sac size might be chosen to accommodate the narrow diameter of the brass casing. Otherwise the pen had to be made even girthier, which may not be possible depending on the diameter of their celluloid rods available. Or it's just fitted off centre in this case that it appears to be a smaller sac for the nipple. But my guess is the former. I didn't re-sac the pen, as it's still relatively new. When I do, I will first have to see if the sac with the right nipple size fits the brass casing. If not, a smaller size sac will have to do, even though it might be a tighter than ideal fit on the nipple.
3. The section is rather thin (partially inner-lined with brass). Be careful not to over-turn the nib unit when you screw it back on, to avoid any chance of cracking the section.
Hope this satisfies your curiosity as it did for mine, and might be helpful to you one day.