I want to get a tactical sling for my 870. Something that will keep it the ready position when reloading and let you use your hands .Does anyone know of one they recommend?

What ready position? Low ready, high ready, indoor ready....

 

Since you need 2 hands to reload (one to control the gun, one to manipulate the shells) the shotgun's weight shouldn't be on the sling and you should have full control of the shotgun while reloading. Also a lot depends on what method you prefer for reloading - a strong hand reload or a support hand reload. Where do you position the shotgun when reloading? Do you keep it in your workspace, or mounted to your shoulder, or stock under your arm and clamped to your rib, or stock in your hip... How do you prefer to orient the the shotgun, ejection port up or down, to the strong side, to the support side? Are you conducting a combat load into the ejection port or a tube load into the magazine? There are lot of variations on the shotgun reload.

 

Regardless, adjustable 2 point slings like the BFG VCAS or Viking Tactics VTAC are the way to go.

You should be able to reload and still have full use of the gun. It takes a small amount of practice.