The bolt handle is attached by induction brazing. The root of the bolt handle has a peg which extends through the rear of the bolt body. There are two patterns of handles. The first version is straight, and the diameter of the bolt plug threads is larger than the second pattern. The second pattern's handle is slightly swept back. The plug threads are smaller in diameter, so the peg is longer - a bit more area for the brazing operation. Both handles can be detached if excessive force is applied. Because of the rear locking system, cases tend to stretch. This can lead to hard extraction, which can result in excessive force being applied to the handle. If handloading, watch your cases and avoid really hot loads. It is not a question of action strength; it is a matter of avoiding hard extraction.
I have reattached quite a few handles using silver braze. Anti-scale compound, heat stop paste and wet rags wrapped around the locking lugs are worthwhile. The locking lugs are close to where the handle is attached, and silver brazing requires red heat.
These rifles are accurate. Had the handle attachment design been better, perhaps a collar like post-64 Winchester M70s, the detached handle issue would have been non-existent. Replacement bolts are hard to find. These rifles have been out of production for years, and a lot of handles have been detached.
Another weak point is the little lug on the bottom of the receiver, to which the trigger assembly is pinned. This little block is a separate piece brazed to the bottom of the receiver. Critically important. Reattaching this piece is not fun.