The OP is right, it does work. I have straightened several 22rf barrels with that method and even a barrel on a 270 Win. There was nothing to lose, the firearms were useless as they were.
A buddy of mine came to me with a Rem Mod 700 chambered in 7mmRem Mag. He had put it on top of the jockey box behind the cab of his truck and drove off. A few miles down the road, he remembered the rifle. Of course it was no longer there nor was it in the box.
He turned around and drove back along the road until he found the rifle. The rather cheap and inappropriate scope he had on it was trashed, the wrist of the stock was broken and the barrel had a noticeable bend in it as well as a nasty scrape on the muzzle. This fellow has a lead foot and I can imagine that once he hit a stretch of road where he could step on it, he did just that.
The stock was easy, I had a spare in the box that fit his rifle. The scope was a different story, I refused to mount another cheapy he had on another rifle that he could never get to shoot well. There was nothing wrong with the rifle/bases/rings.
The thing about metal is that it is relatively elastic under some circumstances. I mentioned to him an article I had read about factories that made barrels using special straightening machines. Called up a bud in Montana with a lot more knowledge than I can ever hope to possess.
The hassles with shipping the barrel to him and him shipping it back were prohibitive. Cost for one thing and no guarantee it would work.
I talked to the owner and suggested the best overall fix would be to re barrel the rifle.
Cheap doesn't really describe this fellow. There is a category below cheap that implies mental issues and if he isn't there, he is very close to it.
Now, the smith in Montana told me about an old trick to try, if you had nothing to lose anyway.
Mark the barrel 180degrees to the angle of the impact that caused the bend and set up a piece of scrap hardwood that is strong enough to take impact without splitting and allow some rebound.
After about 20 sharp raps on the block with the tip of the barrel, there was a definite straightening going on.
I'm not saying swing the thing over your head and whack it as hard as possible, just a sharp rap.
It took several dozen whacks to achieve a straightness that we couldn't detect a bend in with our eyes. We used a laser sighting insert to see if we were even close to being in align with the iron sights on the rifle. We were much closer than I would have thought possible.
We glass bedded the action, mounted a scope that would take the recoil of the 7rem mag and was relatively parallax free out to 150m.
Again, we used the laser to roughly set up the scope to POA.
At 100m his group was about 4 inches. At 200m his group decreased to 2 1/2 inches. This is relatively common for the 7remmag. The bullets don't really stabilize until just before 200m.
There was a bit of fiddling with the elevation and horizontal turrets but the rifle shot within 2-3 moa right out to 350m. That is about twice as far as the owner feels comfortable shooting. He took two bears this spring, a white tail last fall and a moose last fall with that rifle. He used 5 rounds for 5 kills. He won't shoot unless he is absolutely sure he can kill the animal cleanly. He has some good ethics on him.
When you have a bent barrel and nothing to lose, give it a try. I have seen barrels sent to smiths for straightening. The mess and cost didn't justify the results and often the barrels weren't any straighter. On the other hand, I have seen some excellent jobs by certain smiths.
It is a time consuming job and may smiths are reluctant to even attempt it. Not enough money to be made to make it worth their while. Often, they will offer to buy the rifle for its receiver/parts so they can put a take off barrel onto it.
