I think you are right on with the 308. I like the Browning MicroHunter. The gun looks good and is light weight. It's designed with a shorter length of pull for women and youngsters. The 308 loaded with a 150 gr. Barnes X is enough to put down an elk. Teach your wife to shoot well and where to place her shot and she will do great. The Browning will be a little over $500 for a new rifle. If you want to spend less money you can find Remington Youth ADL synthetics in 308 for around $329 in my neck of the woods. I much prefer the Browning. My friend won an ADL Youth in 308 and his son uses it. It's chambered in 308. My hunting partner bought his son a Micro in 7MM-08 and this gun is a tack driver. Handling both I prefer the Browning. But I as most others operate on a budget. You could also look on the used market and buy a full size short action rifle and have the stock cut to fit your wife's length of pull. If you buy her a rifle that fits she will be a much better shooter. Most people including adult males buy a rifle based on a magazine article and change their style instead of buying a rifle that fits them and a realistic caliber to hunt the game they are looking for.