Ah, yes, the Mk1* issue.

The most common "issue" is, as mentioned, chipping of the edges of the guide rail on the right side.

The edges get chipped because the bolt body is floating around in the bolt raceway of the receiver like a frog in a sock. This looseness is generally the result of hundreds of thousands of cycles of the action. All that "prove" and "ease springs" caper had to do something.

As I recall, at least one agency / manufacturer put tiny little bevels on the corners of the UPPER surface of that tiny guide rib on the bolt head. This meant that the occasional clash of bolt head and rail would result in less work-hardening / fracture of the corners.

The problem is, of course, why would the bolt float about to such an extent? Basically: WEAR.

If you look at a Lee Enfield, the bolt is reasonably well controlled laterally; right side support being somewhat less than that on the left.

Vertically, it is a different story.

At NO point is leverage to the bolt BODY completely constrained vertically until the bolt head enters the rear breech ring.

The bolt is driven by the nut behind it and thus all manner of "stray" pressures are applied to it during cycling.

The "natural" thing is that, on opening / rearward stroke, the rear of the bolt tends to be tilted upwards, thus forcing the head down. On a Mk1*, this means that the bolthead "dips. This in turn tends to cause the "lug" of the bolt head to be levered UPWARDS using the flat rail as a fulcrum. Thus, the ends of the tiny rib on the bolt head may start nibbling at the nice square ends of the "retaining" rail.

When the bolt is driven forwards, the "natural" tendency is to push down on the bolt handle as it is driven forward. This, of course makes the bolt head tend to tilt upwards, along with all the attendant / subsequent "lever" activities.

Given that the rear "ring" of the receiver is pretty much a dirty great slot with a couple of relatively small radiused surfaces to actually support all of this bolt manipulation, it's not surprising that things can get a little worn after 60 or more years.

And all of this changes by varying degree when you actually feed cartridges through the thing.

A GOOD TIG driver can probably replace the missing chunks on that rail, (along wth a little tidying up courtesy of Mr. Dremel). HOWEVER!! there is not much point tidying up the rail on the receiver if the rear bearing surfaces are flogged out and /or the bolt body is badly worn.