[Danke]

A log like that is useful for yourself if you have a dozen or so AEGs and pistols.

I keep notes from when I chrono, what BBs, and so on.

I mark scope and accessory locations. Number mags, and so on.

When I change parts I save the old ones I take off in the new packaging.

I print out exploded views from the net and make notes and save all the manuals that come with any airsoft part in one place.

All that is for me though, I don't share it since airsoft guns are inconsistent so something I've found might not work for another person.