I think the buffs remain but are on a short 5 second timer, forcing you to constantly use the shotgun if you want to keep those perks active. I also think that you should be able to use the weapon while riding your sparrow, thus making up for the loss in movement speed but only in PvE or Combined Arms. I was watching Terminator the other day and I thought it would be cool to include that kind of feel into destiny. I was also thinking of changing the description to read "A Pre-Golden Age relic treasured most by one of the first Exo Warminds."