I want to finally begin a project to convert my HS-10B bullpup shotgun so that it will have an extended magazine tube. Problem is, this is no screw on an extension like on an 870. The magazine tube actually has to be removed and fused with another to create an extended length appropriate to hold 6 or 7 rounds instead of the current 4. I found another owner of this type of shotgun who wrote up how he had his done. He said this. You can't get an extended magazine tube from anywhere, so if you want one you must have it made. 1) Get an extra magazine tube from EGunparts or elsewhere. 2) Have a competent gunsmith put it together with the old tube so that is is a minimum of 18 and preferably 18.5 long. Best bet is to measure how long 4(?) shotshells are and compare that with the length of the standard tube, then measure 7 of your preferred shells and leave enough room for spring compression. I mention this because I've found Federal LE132-00 to be just a bit >.< longer than the standard 2.75 inch shell and it adds up after a half dozen are inserted. 3) Use a lathe and have a custom-turned cap made to hold the two halves of the receiver together. It's not a complicated part, all it Really needs is a 45-degree bevel on the inside. 4) Fit, measure, and scribe a line on the tube with the new cap holding the halves together and the magazine tube backed out a full turn or so (to provide clamping force when it's all together) 5) Fasten the new cap to the custom made extended tube and you're pretty much done. ... 6) be sure that the new, extended tube has holes laterally through it like the original tube did. You can use a screwdriver or cleaning rod to provide a turning force on the tube to screw it tight or loosen it. I have already ordered the spare magazine tube. Does anyone know of a gunsmith who can join a magazine tube? I want to take my bullpup shotgun from this. To this. Here are some photos of the HS-10B disassembled.