My 177 46 shoots 7.9 grain crosman pellets at 815 fps, and is EXTREMELY accurate. The 48 shoots much faster, probably close to 1000 fps. I love my 46, but I'm not a fan of the big side lever RWS's, they seem kind of awkward to me (I've had several).
a 300 at a firearm show a while back. It was a nice feeling and beautiful looking rifle. But, the retail price is HIGH! In Canada I believe they are retailing for around $650-700, the guy at the show said he would sell the one he had for $650Cnd tax in, I respectfully declined. For that price I could get a 46 Stutzen, beautiful rifle.
I personally would choose a 46 over the 300, not only because of cost, but caliber choice. The 300 is only available in .177, while the 46 is available in .177 and .22, and maybe more I'm not sure.
But, over all I chose an HW77k for my underlever. IMHO, I don't think you can get a better underlever, especially with that awesome trigger it has. Don't get me wrong, I'm a huge fan of Diana airguns and I have the guns to prove it. I love my 48's, 24's, 34, and my P5 Magnum. The sidelever 48's in .177 and .22 are incredible rifles, accurate, very powerfull, and just plain fun to shoot.
Do you need a "cannon", or a mid-magnum?
Just my 2 cents, I used to have a 48 but know the 46 only from drooling on them at Roanoke.
The 48 is really pretty well-behaved considering its remarkable power, but it is undeniably bulky and heavy and not the sort of thing you wanna plink with all day long.
IMHO the 46 has more than enough power for all but the most extreme airgun jobs. It is much slimmer and lighter than the 48, a very elegant-looking gun. To my way of thinking it is the nicest sporter Diana is making right now. I may not own one...but I want one.