As walshie said there is no legal spec for a Boar rifle, but did I miss it somewhere, is he interested in Boar as well?
If so, then no contest, get a .308, that was my prime reason for a .308, that and a bit of target, its probably 4-5 years since I took it out for any deer.
However, if its just Roe and Reds then a .243, easy on the Roe but don't go throwing it at Reds if they are in the next county.
There are those that will tell you it isn't up to Reds, I would suggest those people learn a bit about fieldcraft and shot placement!
ATB!
It's a fair point. I have shot several