We have been selling quality restored sporters for a while so I thought a post like this would clarify the process. Some of the points only apply to those that use Indian drill rifles as donors, others apply to all rifles.
Initial cleaning : The Drill Purpose SMLE’s are completely covered and soaked in grease for example. After a good wipe-down of the exterior surfaces, complete disassembly and cleaning is done, along with inspection of every single part to be reused. Parts are replaced as needed.
Then, wood parts are stripped of their old grime and DP paint stripes (if applicable). This allows, among other things, to better find defects – splits and cracks, stripped screw holes in the buttstock, anything requiring repair. And of particular attention: the recoil draws at the back of the forend, which will have to be in tight contact with the action’s recoil lugs when forend bedding is taken care of. Some draws come out ok as-is; most will require some shimming; others may need to be completely redone (see picture below for an extreme example that had to be rebuilt)
Fitting of all the parts involve making sure that all parts are serviceable, cleaned, lubricated, have proper fit, and interact together as they should. As is typical of British engineering, one tweak will change other parameters as they all interact together. This part requires skill and maybe a few incantations. Safety operation, proper two-stage trigger pull, headspace, etc. are checked. This is especially important with non matching actions.
After final fitting is done, with proper forend pressure, wood finishing is done with pure linseed oil; final assembly follows.
Last step is an actual test at the range – where feeding, firing, extracting and ejecting is verified. A quick grouping test is also performed, and the resulting target is provided with each rifle.
The result is a rifle as it would come to you after a Commonwealth armorer gave it a do-over. Not your average gun show parts gun
It does sound very time consuming doesn't it? But after restoring more than 200 Enfields and fixing many more, confident hands work fast.