everyone has broken rt side ft 1-1/2 inches just before that small notch in bar. and everyone of the bars have been repaired and also broke same place, person is a high quality welder in all faucet of repair processes. 4-new plus 5 repaired ones.
Action bars are not the quality they once were. Each time I replace one they cost twice as much and last half as long as the previous one. That said, I have never heard of breakage at this rate. Suspect something else is going on, but I can't figure what. My best guess would be a weak action spring and consequently too much bolt speed.
Any chance you are using a barrel that has had the gas ports opened or modified?
I would take a very close look at the Nylon bumper on the rear of your bolt. It sounds quite likely that it has been hammered flat & can no longer act as a buffer as it was designed to. They are easy to replace & I will normally replace one about every other recoil spring replacement. In any case, look to see that there is enough Nylon still proud of the back of the bolt's rear face to act as a buffer; if not, replace it. No buffer = lots of added stress to action bar with every shot.
It does sound like you have some too hot loads or opened up gas ports. I would be sure to verify that your loads are from a reliable published source [weigh several powder charges to confirm they are within specification] and that the gas port holes are standard [hole(s) size depends on the exact bbl being used].
now thats interesting Bazooka Joe, wouldn't tube show more wear on one side verse other, but will check. also will check all other suggestion and I know the recoil spring hasn't been replaced in 4 + yrs.