I'd have to add, that the way srcds interpolates packets for hit registration, ping difference literally means nothing if you have the same stable rates as someone else. The delay between you doing the action and the action being registered on the server is mostly down to interp. This is why when someone else has 30.3ms lerp, but has a different ping to me, the hit registration will be excellent between us (no lerp'd shots, no lag spikes etc). It's because we're interpolating the packets at the same rate, and should hopefully be uploading and downloading packets at the same rate, so we'd technically be in sync.