This design is for the Ruger, 1022 takedown. Use the remix from Diggysquid for the non takedown version (link is below).
I found other conversions you can buy made from cnc cut aluminium and a walnut stock and grips for around $300.00 or you could print this for almost nothing. My goal was to create a Thompson look alike that feels like your shooting the real thing but uses a much cheaper ammo, so this thing is a all around well priced look alike. The only set back is the durability, because this will be made of plastic it wont be the strongest conversion you can make but I think it will cut it. This conversion does not have much contact on the guns parts that get hot, though just to be safe print in something more heat resistant than pla if you can. The hole on the top under barrel part of the (tom rest stl) is made to have a screw placed at just the right height to support the barrel of the rifle so the part will not have direct contact with the barrel. You will need a large print bed (300mmx300mmx300mm) for this conversion, sorry this is a actual size replica its big. The receiver I used in the model was uploaded by mussy, and can be found here. https://www.thingiverse.com/thing:2745722

UPDATE: Just added a new FORE GRIP and EXTENDER for the original Thompson style! suggested by Diggysquid. https://www.thingiverse.com/Diggysquid/about

And hey! Don't forget to checkout a amazing remix of this from Diggysquid, https://www.thingiverse.com/thing:3684581
who has put a lot of work into his remix and helping me with the original:)

WARNING: I have not printed this yet so there might need to be adjustments later, though every thing seems to be dimensionally correct print at your own risk.