This is almost certainly a single shot rifle. And honestly, without spending a couple grand on a scope you will never see the benefits of the rifle itself....
The rifle is likely something like this: ferret50.com Those come brand new from the maker in a box at $3000. If you buy the upper only it drops by $1000 (and you can then use your AR-15 lower to complete the build).....this will make some of your heads swim, the upper by itself is essentially unregulated as its the lower that has the traceable serial number....most of you can simply call them with a credit card number and have the upper sent directly to your house, no FFL needed at all (exceptions for places like California, NY, and Mass).