The model 10A featured a flashlight built into the carry handle. Unfortunately, the batteries of the day tended to leak during periods the shotgun was in storage.
As a result the Model 10B was developed, with the Kel-lite flashlight mounted to the left side of the shotgun. A flip up iron front sight was also added.
Spare parts are available from both Gun Parts Corportation and Sarco. According to an article in Small Arms Review, as of July 2001 Sarco Inc. had enough parts in stock to complete 400 High Standard Model 10 shotguns. Good project if you have several thousand dollars laying around to produce preban semi-automatic bullpup shotguns.
http://www.smallarmsreview.com/sarco.htm
Trivia: The High Standard 10A was featured prominently in the game The Morrow Project.
When testing the shotgun for the first time, discovered there is a reason for the warning to only use high brass shotgun shells. Inexpensive low brass shells from Walmart would not cycle properly in the M10B. After switching to more expensive high brass ammunition, the shotgun cycled fine.
From an ergonomic perspective, the High Standard Model 10B handles well. The only thing I didn't care for was the buttstock, which freely swiveled to allow one handed firing. Personally I'd prefer a solid rubber recoil pad to this spinning piece. I also found the Kel-lite flashlite and carry handle to be unnecessary, and liked how the shotgun handled after removing both items.
This shotgun definately has potential, particularily if the carry handle & flashlight are removed and a small red dot scope (like the Umarex pictured below) was installed.
