I roughed out the shape in the bandsaw and have chose to work from one end, finding the stock in this blank as I go (I’ve let the duplicator sit this one out).  I have the action mostly inlet as seen in the photos and the roughing has begun.
There’s a quarter rib in the works for this assembly and I picked up a set of Ruger #1 style rings for this build to fit to the rib.  I’m not planning any type of iron sights for this so the stock is being set up for using a scope.

To change things up and give myself a break from wood thing, I spent some time with a barrel blank I planned to use.  Before I could do that though I needed to have a close dimension for the tenon.  I took some measurements from the action face to the roughed face of the breech block.  I had been lucky when I sat the blank up and rough machined it.  The dimensions from being square were about .003” left to right and .005” top to bottom.   Better to be lucky than good, but it seems the more I do this the luckier I get…   Placing the block in a toolmakers vise on the surface plate and sweeping it with a dial took a few attempts but it came in fairly close- corrections inclusive.  To the surface grinder it went to true things up a little further.   My final reading from the action face to the breech block when at battery was less than .001” L to R but nearing .002” top to bottom – I’m going to live with that. 
I generally try to part a stub with the mfg. details off the end of the barrel – most times it’s about an inch of material.  From this I’ll cut a sample chamber in it also, similar to what I’ll cut in the actual barrel. I’ll true up the face of this stub, lap it, and use it on the surface plate for a cartridge length gage – for the times I feel froggie and want to sort my ammo.  I’ll also leave the mfg. markings on it so it helps old minds remember what it was – yes, I stamp the underside of the barrel too but sometimes it’s a couple months before I get around to it and memory isn’t what it used to be...  In this case, it is a Bartlein barrel, 1:16, .217/.222” Stainless, 5 groove.  I’m aware that the ends of the barrel may be of a different size than the barrel is but it’s probably a lot closer than most of the other options one uses for a gage.   
I cut the rim fit about .005” in short of target, rough bored the chamber using a boring bar to within about .002 from reamer dimensions while I had this barrel chucked up.  I’m installing a sliding extractor in this and will have to go back in and finish things when I get to this stage, room to work is nice at that point.
For those a little more observant, while I had this breech block in the small vise and fairly close to square to the barrel, before the final grinding I set the assembly in the jig borer and drilled the small through hole for the firing pin... There's a small hole apparent in the ground surface

Now that the barrel is fit up the next move is to determine what sights are going to be used.  This rifle will probably be used for rodent hunting and if it proves itself in the accuracy and handling department it may see use in a NRL 22 Hunter style of competition – not that a single shot such as this will ever be competitive under time constraints… but it will get a lot of head shakes and grins.  All this said, a rib with means of mounting a scope were in order.  Currently my plans are to make a rib, use screws to attach it, and as mentioned previously, cut dovetails and pockets for Ruger #1 style of rings.  The scope in mind is a Night Force with a 30mm tube and 90 minutes of vertical travel.  The vertical travel on a parallel base won’t get me to the required distances needed so I will make this rib with 40 MOA built in.  (.66 degrees for the trig function).   A lot of extra information for most and unless you do this sort of thing it’s a lot of mumbo jumbo.  In a nut shell, I plan to shoot this little rook rifle at distances beyond its realistic capabilities.  I have a couple other rifles already that get used in a similar fashion and they are surprising.
Haven't had time to get back on this build and I usually like to be able to post processes nearer completion than this.  Maybe next week I can get the rib attached and the scope mounted.  I have the transfer bar/firing pin design well under way along with the springs and extractor under construction so I'll post more on this as it evolves.

Looking good. Just finished a similar operation for the barrel seat on a Maynard.
Straight, not tapered and yours looks better.
Chuck

And a few more pix

The pin for the transfer bar to pivot on is a hardened roll pin to begin with but it may evolve to a hardened 1/16” dowel.  The photos show my set up for drilling the pivot hole and for once, everything went as planned – the pivot came out on center of the transfer bar.  The first firing pin was made out of O1 tool steel, trial and error method, no sketches, just turn, stuff, mark and cut, got it first time – better lucky than good I guess.  The second pin will be out of titanium as I’ve had good luck with this material.  The pin retracts about .003 into the block with no pressure and protrudes .043 with pressure applied to the transfer bar.

G.Gil
I was going to do just that, machine out a round to square then I thought different of it - it is a small frame.  Then I was going to do like you do, make it from scratch, but I found an action casting of a square block and got it.  The whole thing is larger so it'll make a nice nitro express.   This has measurements of a medium according to Mr. Winfer
GT

Maybe we need to get rodney interested in a large webley casting set. Like he needs another project. I'm waiting for him to do his maynard project into a complete casting set. Or a bullard!