Actually, I ditched the action screws entirely, and the recoil lug. Instead the whole action is epoxied into the 29mm carbon tube. So, some of the epoxy is also in the action screw inlets on the reciever (but blocked off about halfway with some hot glue, so the epoxy only goes into the holes about a mm or two.) Kind of like glue-in bedding I reason. The only screws through the CF into the action are the ring screws... but I didn't leave them in tight while it was curing. Intention was to have the action effectively bedded (permanently) into the carbon fiber, in such a way as to not create any pressure points that could affect harmonics later.
Then that carbon tube is epoxied to the 3d-print part, which houses the trigger and a spot for me to glue in the recieving end of my removable stock.
I have the option of cutting out the section of carbon fiber tube where the magazine would go... then gluing in a 3d printed magwell. My son's original 3d print lower piece has a magwell that takes regular aics poly mags. But I liked the idea of having a smoother handhold up towards the trigger, as holding it there balances very nicely in the hand... and gives me more area to rest the stock on a tree or other hasty rest if needed. Because there isn't anything in the way of the chamber, its almost as quick to drop in a bullet (which are mounted on the outside near the stock) and rack a new round in, as it is to use the mag (with a bit of practice of course).
Here are some of our 3d print models. Now that we have the dimensions right... I'm thinking about making a drop in chassis version for one of my other kimbers. Probably bed that one more traditionally with action screws and recoil lug intact... I think the final product would be lighter than a factory stock, but far more useful with a pistol grip and AR style stock (then options like folders and removable stocks become an option).