You may find a mechanics tool helpful , it's an external thread chaser . Blue point / snap on makes it .
Most matte finished savage rifles are shot peened / blasted after assembly which leaves a lot of small steel beads in the nooks and crannies , if it's not blown or washed out it will really make a mess of the barrel , which is the softest of the 3 , barrel , barrel nut and receiver .Interesting that the thread galled removing the jam nut. That nut is installed or removed by hand once it is broken loose. However if the forward most rail mount screw (for the scope) was the wrong one that will chew a barrel thread up really ugly.
Doesn't matter. Depending on how badly the barrel threads are you may be able to clean them up with a thread file. Keep in mind that the action is way more expensive than the average barrel so you really want to be sure the threads on the barrel are OK when you are done. Take a jam nut (new one) and run it off and on to be sure. Eyeballing it is not enough.
https://www.amazon.com/dp/B000LE8A5W/?tag=accuratescom-20
Most matte finished savage rifles are shot peened / blasted after assembly which leaves a lot of small steel beads in the nooks and crannies , if it's not blown or washed out it will really make a mess of the barrel , which is the softest of the 3 , barrel , barrel nut and receiver .
Some replace either factory smooth nuts or factory nuts thinking an aftermarket will be better or maybe he was going to sell the barrel ? Your guess is as good as mine .I agree, however, the op said the jam nut did the damage. There is no need to remove the jam nut. (meaning to turn it back any amount after it is broken free) You break it loose and unscrew the barrel. Then 90% of the threads on the barrel are visible for you to clean them up and then unscrew the jam nut. That's why I can't understand fully why a jam nut would be turned any further than to break it loose and cause the damage. I have bought a number of Savage actions (new). The threads in the action always seem to be loaded with debris. But the jam nut, once the barrel is unscrewed then comes off. As I said all those threads are right there available to be cleaned.
I have seen several barrels the threads got messed up and ever one was from the front base screw being too long . Larry
The backscrew can hit on the bolt head also . Seen that many of times also .I think I mentioned that in post #5 Larry. I agree with you 100%....my experience is that screw is the culprit.
I actually have a barrel that someone had turned TWO full revolutions with that screw embedded in the threads. Peeled the threads right off. I should have asked what type of barrel vise or action wrench they were using as it is an impressive feat. That too long screw becomes a perfect set screw!
I galled the threads on a barrel getting the Savage nut off. I need a 1.055x20 die. Does anybody rent them?
Bill