My Motorguards are all converted M30's with handmade internals. Ralph was kind enough to send me a pair of the nylon units he used to make before he passed on, but after that I had to make my own, as well. The last one I made had a little engineering built in by fabbing a telescopic internal sleeve. All you need is two pieces of pipe with a snug slip fit, then weld the appropriate size washers on the ends. This design eliminates any possibility of internal compromise and ensures the unit will button down tight.