Tex, from my experiences, the 180grn boundary that you mentioned between the .308 and .30-06 is pretty much the dividing line where the .30-06 starts leaving the .308, I've never noticed any real advantage in either cartridge up to that point, and if you're hunting something that can't be killed with a 180grn bullet from a .308 OR .30-06, you'd be better off taking a .338WM or something larger.

There are several undeniable advantages in the .308win...in loadings that are essentially equivalent (within 200fps), you're likely to get considerably less recoil in the .308 which increases shootability no matter how long you think yours is. The short action also promotes inherent accuracy and better bolt lock up. Typically it uses less powder to get the same results as well, and .308 brass usually has a slight advantage on price as well, so it's cheaper to reload. Basically, if you find any game species that the .30-06 can hunt effectively that the .308win can't, I'd like to see it. The .308win also typically retains more velocity than the .30-06 in shorter bbls. From what I've seen, reducing a .308's bbl from 22" to 16.5" gives about the same percent velocity loss as reducing a .30-06 bbl from 22" to 18", and truth be told, if you get down to about 16-16.5", the .308win passes the .30-06 on velocity...Of course I only found this out after I spent the money to cut and recrown an M-77 Mark I .30-06 so I'd have a compact .30-06...my Fiance bought a stock compact .308 Mark II and she's getting about 80-130fps better than mine using the same powder's max recommended loads.

To address the question at hand, the M77RSI is a great gun. I've owned two of them, and three No. 1 Internationals, they're definitely something else...a very distinct look. The increased stock does increase the weight of the rifle for no extreme shooting advantage (i.e. a thicker/heavier bbl is more accurate typically)...it's something to consider if you're going to be carrying this thing very far. If I recall correctly, Ruger claims they're an extra pound over the standard model...they're also more balanced towards the muzzle, it feels good for some people, it's uncomfortable for others. I bought mine for the looks, don't really feel TOO discomforted by the balance change, but the look of them is really the only reason I bought them.

I've got mixed feelings about them for rested shooting...On one hand, I like them because I don't feel bad bedding the whole length of the stock on something on a table while shooting for better support since it doesn't knock the bbl like a standard rifle would, however, the muzzle stock lug might also be pushing up on the muzzle when I rest the rifle, which migh be flexing the bbl moreso than it would in a standard stock.

I'd say buy it, you can always sell it off if you don't like it, and you might even be able to return it if you've got a good shop.