Sorry, but definately NO! This is still a WH40K-Game and therefore should stick to the lore as much as possible. Might they had such things in the Dark Age of Technology (roughly arround 25th Millenium) but in ‘current’ times they have not, because “so much has been forgotten, never to be learned again”.
But as I pointed out in this Thread, there is enough of cool options from a lore accurate standpoint.
And these addiotions might bring some problem solution for the shotgun to the tabel, too