Winchester Mod.100, Remington makes a semi auto .308, Browning BAR, and there are several military or tactical style .308 semi's for you to choose from. All of them have detachable magazines and are easily set up for optics if you so choose. Google is your friend as well as gunnutz. I have a Mod.100 Winchester and though it's an older rifle, when I got it you could call it basically unfired. It had only seen 20 rounds through it. I find it very finicky when it comes to ammo and though I'm know I'm picky as to "acceptable" accuracy, I did manage to work up an hunting load that performs well. My buddy's BAR was more accurate, but also finicky as to ammo and a lot heavier than my Winchester. My brother loves his 7400 Remington, but it's a pig to strip down to get at the gas system, which is a common fault with many commercial semi auto's. If you like the tactical/military look, the Robinson XCR, the Norinco M 14 clone, or the BCL 102 may suit your needs. A lot depends on your budget and the intended purpose. Good luck, whatever you settle on.