Well, in some ways I'm feeling quite proud as I've just taken a string off my violin and put one on again - the first time I've done it single-handed. The minor hitch is, I ended up putting the same string I'd just taken off back on again. The wound bit of the string at the ball end seems to be too thick to fit into the tailpiece. This is a dominant G string, as is the string I took off and put on again.

Any help please?

Strange... try hooking the string in higher up where it should be thinner.
I've got dominant strings and only one bottom tuner (black twiddly bit) so I have to tune it with the pegs), which makes the pegs easier to handle and strings easier to change...
A G string? What was wrong with it? Usually the lower strings are fine?
(Ds and Gs hardly ever snap while you're tuning them, especially with dominants: whereas my E snapped in my face one cold morning when I tweaked the tuner...)

Good luck!

For some reason Dominant seem to wind a little too much winding and thread onto the ball end of the string. Combine that with narrow slots in a tailpiece and it leaves people with a bit of a problem.

You could try flattening down the offending bit of the string with a small pair of pliers, or, try pushing the string into the tailpiece slot with something like a small screwdriver - but do be careful it doesn't slip and dig into the body of the violin!

Failing everything, contact a luthier. They will be able to make the slots in the tailpiece just a little larger - enough to accomodate the thick string winding, but not so large so as to end up with the string popping out.

Thanks both of you...will try the pliers etc Amanda and give it another go...is it just Dominants this happens with? It came in a full set of brand new dominants so I suppose the shop might take them back.

I've had the occasional Pirastro string with a similar problem, but for some reason Dominant seem to be the worst. Pirastro are completely handmade strings, hence their price, but also why the winding maybe more consistent. I'm not sure about the manufacturing process of Dominant .