Thanks for the responses guys but i guess i did not explain myself clearly. I meant after a factory or custom action has ALREADY been trued and lapped when does this process need to be done again. After 5,10, 15,000 rounds, or is the wear so minimal does it ever need to be done?
CA48-Your question means to me an explanation of what truing an action and lapping means, needs to be squared away first to answer your question.
Truing an action in laymans terms means to make the following three surfaces concentric/parrallel with one common reference/centerline...the bore. When truing an action this usually means-
1. Action threads are "chased" to ensure when the action is screwed on your barrel, that the centerline of the bolt raceway points straight down your bore.
2. Action face that contacts the exterior shoulder of the barrel and interior shoulder of the barrel meet with as close as possible 100% contact or "mate up" as the action is "screwed" onto the barrel. Ensures your recoil lug is flat/true and doesn't introduce any stress in the action/barrel junction on non-Wby builds
3. Bolt face is touched to ensure it's surface is exactly perpendicular to the afore mentioned centerline of the bore/action
Lapping lugs...
1. A lapping or "mild grinding" compound is placed on the bolt lug/action lug abutements. Rearward pressure is applied to the "trued" bolt face...bolt is cycled against the action lug abutments, until the smith sees 100% contact with all lugs/abutment surfaces, or as close as is possible.
So by understanding the above procedures, you can see "truing" shouldn't need to be done unless you had introduced a large amount of stress to the rifle (i.e. driving a tractor over it because it doesn't shoot like you want it to
)
Lapping the lugs could potentially be a "wear" type item, but this would take an excessively high round count with the bolt being placed in some kind of binding/eccentric position over many rounds...or potentially bolt lug/action abutment setback due to overpressure loads that would cause one lug to start picking up the load before others.......both seem to me very specialized situations, not likely encountered.
During a rebarrel, a smith concerned with the precision capability of the rifle, especially if it was due to accuracy/precision concerns with the rifle in questions, would verify the above surfaces are true/lapped, and then decide it retouching the surfaces was required.
JE Custom or some of the other super smiths on this site that build lasers....please step up and fix me if I'm off base here.
Hope that helps.