Ok, well I may just need one of these... If only I had infinite money.
From the manufacturer's website:
The PSE TAC 15 has taken the crossbow market by storm. The ability to convert any standard AR 15 lower into the most accurate and powerful crossbow on the market, the PSE TAC 15 has become an instant favorite for hunters and AR enthusiasts.
But what if you don't have an AR 15 lower? Now all the revolutionary features and benefits of the PSE TAC 15 are available in the new PSE TAC 15i. Featuring a fully adjustable stock and crisp trigger, the PSE TAC 15i is sure to be the hottest hunting crossbow in the woods.