Yep, you heard it here first. I think. I inherited my father's machine shop when he died way back in 1977--lathe, milling machine, shaper, etc. I worked on guns to feed my kids from 1975-1980. I have been certified in several welding criteria. And to top things off, I worked full time as a machinist from 1982 to 2004. I built a box-fed Remington 870 in the early 1990s, to include making a whole trigger assembly to work with the box magazines I made. I made my own falling block style rifle that shoots .50 BMG. Everything except the barrel was home made. Heck, I even built and raced a funnybike in the 90s, again building the engine and frame myself. By no means am I bragging. Seriously. Just setting the background for my announcement. I have decided now that I have been retired for a few years, I am now longer raising my grand-daughter, and I successfully divorced my wife---my bucket list consists of a total of ONE item---to build a .410 A5!!!! I am 98% certain as long as I don't sell it I would be completely legal, and it would be just difficult enough to make it interesting. I already have a couple of Remington 870s in 12/209/.410 so I figure I could use those dimensional differences regarding what measurements would have to be scaled down for the smaller bore, etc, and what dimensions would stay closer to "normal/standard" size, such as LOP, etc. The receiver in and of itself doesn't look to be TOO hard, and the wood would be relatively easy. All the internals would be pretty easy too, but the one thing that is giving me some concerns is the barrel. I cannot decide if I want to turn the barrel out of a much larger piece of steel and offset my machining to incorporate the magazine lug as part of the barrel, or simply turn and bore a barrel, then weld on a barrel lug for the magazine tube. The barrel extension will be another major issue. I can easily make it and have it hardened to whatever Brinell number it needs to be, but to "properly" install it is admittedly beyond my current knowledge at this point. Oh well, I'll burn that bridge when I get there. I have seen plenty of other people make operable miniature guns-so why not???? (And yes, it will be a round-grip butt stock, thank you very much for asking.) Hmmmmmm.....I never thought about the engraving...........hmmmm.