I've owned a couple of A Bolts for many years. A stainless stalker in 300 WM and a blued synthetic in 338 WM. Bought them both new and they were two of the best factory rifles I ever owned. I tried many loads in them including a few that went over max and had to be dialled back and have never had any problems with the bolt. The triggers were difficult, the stocks had to be reinforced to get the flex out, and the barrels are tough to remove, ( I shortened both and put a muzzle brake on the 338), but the actions have been solid and smooth and both rifles are very accurate. I've taken some of my best animals with them. The only thing I can think of on yours was perhaps that one lug was the only one making solid contact. A Bolts are a cast receiver maybe there was a defect in the fit.