I am trying to attach a sling to my Remington 870 Tactical with the factory upward folding stock. Here is the problem: The weaver sling hole on the forearm is big enough for a standard weaver sling swivel. The hole on the back of the stock is too small.... so I cannot attach a weaver sling mount to it. I went with BlackHawk! sling attachments as they are as standard as I could find. What are my options to attach a sling to my Shotgun? Here is a pic of my shotgun for reference.