what tool to use for the magazine cap or remi 870 12 ga

[akubly1]

I recently purchased a sling along with the hardware that is need to mount the sling. My issue is that I am having a hell of a time getting the original cap off so I can replace it. Do I just grab a wrench and go to town? or do I use a rubber sling wrench and try it that way? _Please help

[Synchronizor]

The best tool I've tried is a pair of channel-lock pliers. Put a piece of scrap leather or heavy fabric in the jaws to keep from scraping up the cap, and it should come right off. See this video.