Unfortunately I have to contract out the serious work, I don't have the tools or the skills involved. AllenM does and he'd be a good choice for the work!
It started as a Rem700 5R Stainless. After the original barrel didn't deliver like I'd hoped I bought a barrel blank and took it to Ray Saltzman. He trued up all of the critical surfaces of the bolt and receiver, cut the barrel to my desired length, threaded both ends, cut the chamber and torqued it onto the receiver. I'd love to be able to do this type of work, maybe someday.
Man, I still have a LOT to learn about rifles, and your's is a fine example of the exciting things that can be done. You're right about AllenM, he is amazing. He's done some great repairs and rebuilds on a couple of 1911s of mine. I'd really like to build one of these, very cool.
Mine came in last week. My barrel is to large .950 @ the muzzle. These stocks are good for up to .940 @ 5 1/2" ahead of the chamber. I do not think there is any opening up of this barrel channel. But all is not lost. It is looking nice with my .223 R700 sitting in it. I really like it. For the price it is a no brainier.
My .223 had a serious truck axle of a barrel on it, I had it turned down to a much more manageable profile.