I've "fixed" a few Winchester 1897 butt stocks. Probably resurrected is a better description. I watched a few videos on the subject, for hints and warnings.
There is an expression, if it ain't broke, don't fix it. Your 219 stock is not broken or cracked, so nothing to fix. However, anything that you can do to prevent cracking or failure is a good idea.
I threaded brass welding rod (brazing rod) threaded it across the cracks. Unless you can predict where the crack may start, it may not be that effective, but it will not crack across the brass rod. You mentioned cross bolting, but I think you were referring to "pinning". Pinning was a standard procedure for military military armourers. The process is simple, but does take a bit of patience, and some planning.
This was a pretty much scrap 1897 that I resurrected. The list or repairs was long, but if you look at the wrist, that is the pin I used to stabilize a crack. The point I'm trying to make is that pinning is not an invisible fix, it is visible. Making an invisible reinforcement is challenging, not much wood to work with.
The real killer on this is having a loose retaining bolt and/or oil soaked wood. You haven't posted a picture so it's hard to know what you are working with. One of the previous posters described a good method for reinforcing the wrist on a bolt action rifle, which of course is not applicable because the retaining bolt runs though the middle of the butt stock. If you want advice on an issue, posting a detailed picture(s) is a good idea.
Larry Potterfield has a few good videos, but my favorite is Anvil, mostly for his dry wit and his willingness to follow Alice down the rabbit hole. Acetone does a good job of removing soaked in oil. Tung oil is a tough finish and if you top it with a bit of Tru-oil, it will give you a decent finish. This is a down and dirty, lazy man stock finish, but nearly the equivalent to a hand rubbed linseed finish. Most purists will scowl at the job, but if you use varnish, most purists will have a full blown seizure.
https://www.youtube.com/watch?v=AAMspI1BeyI&ab_channel=MidwayUSA
https://www.youtube.com/watch?v=BO-CoUTmD5A&ab_channel=MarkNovak
The above links are just to show what is out there in You Tube land, enjoy.
You can go to http://www.ktgunsmith.com/win97.htm for the full story, here is the part on pinning.
I'll quote:
Repairing Butt Stock
The butt stock was cracked on both sides of the wrist so I decided to try my hand at repairing the butt stock. I took a tapered wooden plug and forced it into the round opening at the front of the wrist to open the cracks just a little; about the thickness of a business card. I mixed some JB Weld epoxy and forced it into the cracks with the edge of a business card. I removed the plug and clamped the wrist to hold it tightly closed. As the epoxy was forced out of the crack I wiped off the excess.
Since the stock was cracked in two places I wanted to install two reinforcing pins to keep the crack from spreading. I threaded a piece of 1/16” brass rod with a 4-32 tap. I drilled a hole with a #44 drill bit from the top of the wrist through each crack.
I cut enough threaded rod so it would fit into the hole I drilled, and into the chuck of my drill. I coated the threads with epoxy and used the slow speed of my drill to screw the pin into the hole. I removed the pin from the chuck and cut it flush with the stock. I filed the end of the pin so it was flush with the stock.
Many military surplus stocks are pinned in this manner. I could have cut each pin short, cut a notch in the end, screwed it below the surface of the stock, then filled the hole with epoxy and wood dust to completely cover it up, but I like the fact that the pins are visible. All of my shooting friends tell me this gives the gun character, and I got to keep the 100-year old stock.
Caveat: I followed the methodology, but used different sized rod, threading dies and drill bit sizes.
