I love the 6.5 rem mag, I have a 700 in that caliber and like the others have pointed out it was the one of the first short mags. A sweet little round that is awesome deer round. However if you want the 660
For your collection then by all means buy it. If you just want a deer rifle for your grandson I would choose a different round. It's hard to find brass and the slow twist keep your choices in the 120 grain bullet range. I found a fellow LRH site member Who hooked me up with some I fired brass at a good price. If you make the purchase and need a source PM me , I'll put you in touch. BTW love those little 600's and 660's , cool rifles.