Just a tip: Never, ever fire that Lee near any zombies or people you don't want to inadvertently cause the death of/be killed by, it's extremely loud and it wouldn't surprise me if some people would kill you just for holding it in case you draw a swarm of zeds to them! To be fair, though, no one really needs a good reason to murder people in Day Z, I mean I've shot people simply for not being me in the past.
Your best course of action would be to swap the Lee for anything, literally any gun is better than that. Yes, it's powerful and it's got decent range, but the sights aren't that useful at the kind of range you need to use it to be out of earshot (I think, I've never actually used it except for in a panic situation, which Ibo may remember) so you're better off with a Winchester or M1014.
But if you do get seen by a zed, run a long, long way before you shoot it, zeds can't catch up to you to hit you as long as you keep running so you can go as far as you think is necessary (which is as far as you thought was necessary plus 100 metres), just don't run up any hills because you slow to a walk which is pretty annoying. Also zeds can't run while indoors so you could use that to your advantage to put some ground between you and them, but to be really useful you need to gather up ALL the local zeds into a train then pass through a long barn. By the time you leave through the other side into zombie-free air, they'll be about a quarter of the way through so keep running and put objects between you and them to break their line of sight, then go prone and wait and see what happens.
Anyway, I'm digressing. Just be really careful with that Lee Enfield, it is to your audibility what running around with a flare is to your visibility.
