Great Britain, and most of the rest of the commonwealth used the .303 British as their standard military arm from about 1888 till the 1950s. There are several different variations. Look yours over carefully.
The SMLE (Short Magazine Lee Enfield) is the most commonly found, and the most common types are the No.1 Mk III (WW I era) and the No.4 Mk I (WW II era). If the sight is on the barrel, it is probably the older gun. The later one has the rear sight on the receiver.
There is also a No.5 Jungle Carbine. They were not made in large numbers, but many earlier SMLEs have been "trimmed" to resemble them. Real Jungle carbines bring a fair penny, but the copies aren't worth nearly as much. Some folks ask high dollar for what is actualy a copy, thinking they have an original. Don't be fooled.
You don't mention if it is in military trim, or if it has been sporterized. Value of the GI issue condition guns has been going up recently, sporters have not, rather just the opposite.
Chambers are "generous" to promote reliablility in battlefield mud & dirt, so case life for reloading is fairly short (even if you only neck size). Check the bore, if it is good, the rifle will probably be a good shooter. Even if the bore looks poor, the rifle may still shoot acceptably well. They aren't target grade guns, don't think you will get MOA accuracy. But they will shoot quite well enough for big game hunting or casual plinking. Some of them actually shoot better than that, but don't expect it.
