One large enough to get all your kit in but wont hamper smooth mounting of a rifle or catches the stock/action when slung from shoulder. Something of a tall order if my experience is anything to go by. The real killer being the proliferation of those handy but hard plastic shoulder strap and hip belt adjusters.
If you don't have a rifle though .....!
Cheers

If you don't have a rifle though .....!
Cheers