I've just bought a new Epiphone Casino and I'm having serious tuning stability issues. The G string is the worst, anything other than the slightest bend will knock it out - not a little flat, but jarringly flat - while overall tuning is unstable.

Generally, strings are more likely to be flat than sharp, but I'm lucky if I can play for longer than 10 minutes without it sliding out tune.

I've only had it since last Thursday, so it probably needs a set-up at the very least (the action is a mile-high and the fretboard needs oiling etc) but has anyone else had this sort of experience with Casinos? Should I be concerned that this is going to be an ongoing issue, because my Snark is threatening to go on strike from overuse.

I should add that also I have a 1990s Japanese Squier Strat, which while it's not perfect, can at least be relied on to hold its tuning even with some aggressive string bending.