There is no way of knowing when it will be back in stock. Recommend you add it to you wish list, if you haven't already, and Bud's will notify you when it is available. You may want to consider becoming a Team Bud's member, if you aren't already, as Team Bud's get first shot at hard to get items.

You can place the weapon on your wish list. Buds will notify you as soon as a shipment arrives.

You can place the item on your "Wish List" from the item description to be notified by email when it is back in stock for purchase. I have setup an email rule that sends a high priority text to my phone for quickest notification for "hot' items.