I've got a 1950's Marlin 336 that was my grandfather's. Before coming to me, another relative had the left side of the receiver drilled and tapped for a 4 screw hinge-style scope mount.

My question: is it possible for a skilled gunsmith to weld or otherwise fill the screw holes to make the receiver look original and undrilled? I do not want to use filler screws if I don't have to. I know it'd probably be cheaper to find the same unmolested gun but this was my grandfather's so I'd like to spend the money on this one if I can get it done for a fairly reasonable amount.

I know that if it is possible, I'd need my gun reblued and I'd like to have that done anyway. I do not care about any collector value as it'd be one of the last two guns to leave my possession.

Yes, that is called restorative welding and it's not a big deal to someone who knows what to do, but you are correct in that it will require a full re-finish.

What is done most often to to use a plug screw of mild steel and set it about .020" below flush. The "pit" is then TIG welded over and filed near flush. Lastly the welds are stoned and polished down to a dead flush surface. In most cases the process will go back to a few small welds to get all the edges of the weld and original surface even and fill nay slight imperfections.

When it's all flush and totally hidden you are ready for the re-finish. When done for museums the finish is generally done in an "antiqued process" so the finished product will be in perfect working condition and in original condition too, but not have any appearance of being restored. just a perfectly working original.

If done for individuals the call is all up to the customer.

Some want it made "like new" and some even want it done in ways that are prettier then new. Doug Turnbull has become famous for doing that kind of work to the highest degree of skill and beauty. His restoration as color case hardening are the standard by which others are measured.

Turnbull's work while arguably the best in the business is definately not "fairly reasonable". There are other 'smiths out there capable of producing what the OP is seeking for a reasonable price. One thing to keep in mind is that while the weld repaired holes can be finished to the level of the receiver there is a possibility/probability that they will not be the same color as the receiver due to different material of the weld.

Yeah I can't afford Turnbull. Do you guys know of anyone who can do the fix well for a reasonable amount?

And I'm not concerned if the fixes are slightly discolored after rebluing. I understand that it's a nature of the fix.

I know this isn't what you want to do but I would screw in some blanks and give it a while to see if you could live with it. Sometimes big issues become little issues with a fixes like this and a couple months of patience. Best of luck.

Ed LaPour, Bremerton, Washington, did such a fix for me- and did it well- a few years ago. Don't recall the fee he charged and it would be outdated anyway. He is a pleasure to talk with on the phone and can tell you about his present shop rate and backlog. And yes, there is a bit of shade difference after blueing.

+1 on Ed La Pour, Ed has done several jobs for me. He is a pleasure to deal with, his work is first rate and his price and delivery is very fair. I can recommend Ed without reservation.

why not just fill the holes with epoxy, sand down smooth and cerakote it?

Give this guy a call:

http://www.restorativewelding.com/Welcome.html

screw in a screw without a head and leave it .020 tall. Hit it several licks with a 3 oz hammer and it will swell the shank. Polish down to level and reblue the gun. I did it that way many many times. Your gunsmith shouldn't have any problem doing that. If you resort to welding it needs to someonr that understands firearms, heat treatment and rebluing. Your Marlin bears the stress all the way through the receiver since the recoil lug is behind the bolt.

If it was me, I would leave it as is. You can buy another Marlin cheaper than what you would pay for first class work filling those holes. They have no effect on how the rifle performs. I've spent a lot of years trying to do exactly what you want to do and it always comes out being expensive and you still have a rifle that you can see the holes from inside the action.

I would find a mount that fits it, probably a Pachmayer, and scope it and use it.

There is no shame is keeping it the way it is.

When I first started working on guns I had a worn out Remington 11 that was my Granddad's bird gun. I polished out every pit, replaced the old wood he had repaired and replaced every worn part. Then I hot blued and it looked like brand new. I felt like a fool. That old gun had scratches from when Grandad ran from the Warden. It had rust from a 100 times he crawled in the salt marsh and it had his hand work in a couple of amateur repairs. I would love to have it back like it was before I made it new and wiped away every trace of him.