The reason I offered the letter is that it relates to the mounting of an AOW shotgun (which, under the law CANNOT have a stock) to an AR rifle. Mounting it does not create a SBS out of the AOW. Ergo, the stock of the rifle is not considered a stock on the AOW. Expanding that, the pistol should be treated no differently.the letter only addrsses aow's. which is good to know but still doesn't quite answer my q's about title 1 pistol connected to title 1 pistol.