Can You Use Rifle Recoil to Power a Jetpack?

The recoil of a rifle can leave quite a bruise if you aren't properly braced. Most people only have to learn this lesson once. A young man named Rob noticed this force and imagined making a jetpack out of the recoil force of a rifle. Is this at all plausible? He submitted it to Randall Munroe and Henry Reich of the What If? series (previously at Neatorama) as a theoretical question. They tackle those questions seriously, no matter how dumb they sound. The answer is "sort of," meaning that you could do it, but it would be difficult, ridiculous, and not worth the effort. 

But there are guns that have more powerful recoils than a mere rifle. And that's where this theory gets interesting. Not that we're ever going to try making a jetpack from a gun, but the existence of a gun that could do it is both interesting and unnerving.