I have a Supernova Tactical Comfortech that serves as my primary home defense firearm and I have immense fun shooting in the South Florida Pistol Club's USPSA Multigun match every month.
However, I also want to try some trap or skeet shooting, and my preferred range (Markham Park in Sunrise, FL) has a very nice, large trap and skeet range but requires all barrels be at least 26" so I could not shoot my 18.5" Tactical there. I am also planning to go bird hunting in March with a friend.
It's quick and easy to swap back and forth between barrels on the Supernova, and Carlson's sells long hunting barrels for it at reasonable prices. Seems like a good solution, so I got a 30" barrel from Midsouth Shooters Supply for $228.
I had a more difficult problem to solve, though. My Supernova has the ghost ring sights, which I do not want to give up permanently, and I do not want to remove and reinstall the rear sight every time I swap barrels. The fiber optic front sight on the 30" barrel is far too low to see through the ghost ring and still be aiming straight. So I needed to find a way to get a taller front sight installed on the barrel to match the height of the ghost ring rear.
I took precise measurements all over the shotgun and both barrels and then looked all over the internet investigating every product that looked like it might fit and might be tall enough. I didn't come up with much, so I started looking into making one myself.
The fiber optic front sight on the 30" barrel is threaded into a hole in the rib. I measured the threads at M3-0.50 and the depth of the hole at 4.5mm. I later discovered that the hole is not actually threaded all the way to the bottom. In order to reproduce the height from the bore centerline of the tritium dot on the original front sight post, I needed about 15-16mm above the top of the rib.
I found this 316 stainless steel M3-0.50 shoulder bolt with a 4.5mm threaded section (same depth as the hole in the rib), 12mm long shoulder, and 3mm high bolt head, for a total of 15mm above the surface of the rib. That means if the top edge of the bolt head is cutting my target in half horizontally, I should be lined up almost perfectly.
http://smile.amazon.com/gp/product/B00GZYBXDI
Once it arrived, I tried threading it in by hand and immediately figured out that problem I mentioned: The hole is 4.5mm deep but the threads are not cut all the way to the bottom.
I have an M3-0.50 tap, but it is not a "bottom tap" so the end of it is tapered and will not cut threads all the way to the bottom of a blind (closed) hole. I purchased this set in order to get the bottom tap:
http://smile.amazon.com/gp/product/B00FXK8DLA
Even though the photo shows a bottom tap with the least taper of any M3-0.50 I could find on Amazon, the tap that actually showed up was not the same as the photo. It had about a 45 degree taper at the end:
Oh well. I ground the end down until it was flat enough to cut threads to the bottom of the hole.