FGC-9MKIISD fixed low rail set for the short shrouds

the bolt on UNW low rails are not that strong. but I didn't think about adding a fixed low rail option for the short shrouds as well. so here thy are. and I also added the stock shroud model so you can have the original look with the MKIISD update, and fixed low rail option.

-- what does the MKIISD update mean? in this update did I reintroduce a version with a small rail on the side. those will will have the words SR at the end of there name standing for SMALL RAIL.

the main update and why these are called MKIISD are that I took some improvements from the FGC9 SD and placed in the MKII shroud models that I designed. but keep in mind the are still made to just work with the MKII this is because the rail stands higher then the SD does.

so the magnet design of the MKII have been removed. and the SD style magnet have been added. the to install it is basically the same. but you will be using a cylindrical magnet with a OD of 5mm and 10mm long in size.

and wile I’m add it did I also add the grove that prevents the barrel from rotating.