Here you go: a Leupold VX III 3.5-10x40 scope on sale at
MidwayUSA for $399.00. Yes, I know you want to keep it at under $300.00, but the $399.00 sale price is so good that you should buy it while you can!
Index matched lens system and lifetime warranty, my friend.
Put something really good on that 7mm mag, and save a bucket of money while you're at it.