Some more food for thought... Thanks for the detailed pictures. Your source said he built the gun... not Len Savage. The design is the Historic Arms design... but there are details pictured that point to it being a home built. Whether it has ever functioned reliably is undetermined. Did the seller say what components were purchased from Historic arms? If the striker spring came from another source then it may be too strong and is prematurely retarding the rearward movement of the internals. The recoil spring shown appears to be the standard outer spring or a Mk I. You have an original gas piston shown installed on the bolt carrier (not the usual US made version found on a Historic Arms produced gun - to comply with 922r US made parts count) so it could be that you're also bleeding off gas from a worn piston, or oversized gas cylinder bore or some combination of both. As you indicated... In many cases the gas port in the barrel and the largest orifice in the gas block were drilled over sized by Len to allow for more gas to drive the system. Adjust these holes conservatively and in small increments as once removed... metal is hard to put back. If Len did not build this gun I can understand why he is hesitant to try and address its current malfunctions- too many unknowns in its construction. Hope it works out for you.