I have a Spanish M43 8mm Large ring Mauser that has been fully BUBBA'D.  The stock has been sanded so thin that inlets for your fingers are not even there, but it is pretty.  They seem to have also removed the heads of metal recoil crossbolt on the front so they could inlet coins in each side of the stock.

My problem is they took the rear sight off and drilled into the barrel right over the chamber to install a Williams rear sight.  Is this unsafe?  I though drilling and tapping holes over or just in front of the chamber was a NO NO.

This. I love when people do this. What a great way to cut the value of something in half or down to near nothing.

Maybe you could part it out and get something you want.

So I am looking at a new barrel. Ouch.  How much to get that done?

What about the stock, I don't know how the crossbolt recoil lug works, but would I be able to salvage the stock with a  new crossbolt and glass bedding?

I would like to save this gun as my day has attached sentimental value to it because it looks like a rifle from his youth.  Im afraid I would be better off buying another gun and "bubba" ing it myself to look like he wants, but keep the military sights and functional parts intact.

Its a shame.  This one has the best bent bolt conversion I have ever seen, is butter smooth, and looks really pretty.

You can always try running a screw till it bottoms out in to the hole and seeing if the fired brass shows any signs of damage in that area. Keep your face far from the hole until you figure it out though.

LOL. no I know for a fact the holes are not all the way through.  The question is whether the barrel will ever rupture at the screw holes.  I am not worried about pressure coming up through the screw holes and blowing the sight off (though that would also ruin the barrel completely).  I am worried about the whole chamber splitting like an old stalk of bamboo.

Oh, nope that is not going to happen. the barrel is still plenty strong, even with a 1/8" hole in it.

Shoot it. I wouldnt give it a thought its been done a lot with all the bring backs and bubbas shop working into the night over the last 50 60 years.

Wait....is there a real danger of the barrel rupturing or is this just a cosmetic/bubba issue?

is it really worth the doubt?

if in doubt rebarrel.      or show us pictures so we can see whats up

Post some pics. I think its' good to try to restore it because of the family value. The parts might end up costing more than it is worth. I'm sure someone here can point you in the right direction.

 Plenty of used 8x57mm large ring bbls out there.

Then just get a Lothar Walther stepped barrel and be done with it

Dunno.  Have a Turkish small ring action that came w/ bbl for $40, maybe?  They screw in, so installation's not a real issue.  Headspacing is a bit trickier - have no idea.

Well, why don't you enlighten everyone & put out a rough cost estimate out there, instead of tiptoeing around & dropping hints?

if the action is solid and not to messed with, you are going ot have the cost of a proper action vise, the cost of a new barrel  and a reamer tied up in it.  

way more than $250.

and also the sights are soldered on and will have to be relocated once the new barrel is installed. I have had this done over twenty years ago swapping to a 308 barrel.

Jonathan, do you want to keep the original caliber?  If you are planning on changing the barrel, you have several options.  You can fully sporterize it, by going to a different caliber and a sporter style barrel contour.  Drill and tapping the receiver for a scope, but that means forging the bolt for a scope or cutting off and welding a new handle on.  But that opens your caliber options up from 22/250 to 458 Winchester magnum.
Or, do you want to keep the original 8mm caliber?  That means finding a new, or unmolested, barrel.  If you want to keep the same military style barrel, you can often find used, surplus Mauser barrels on eBay or Gunbroker.com.  You might look into a take off Yugo M47/48 barrel, as they didn't get used and abused in a war and are often in pristine shape.
Either way, no matter what you do, you will need access to a bench vise, lathe, a receiver wrench, barrel vise, a chamber reamer, and head space gauges.  It isn't hard to do, rebarreling a Mauser is easy, as long as you have an idea of what to do. reamer and head space guages can be rented, the other tools can be borrowed.
If you lived closer I would help you.