Rick,

Most Remington 870's have a 1-35 twist rate. That is the most important factor when trying to consider sabot performance in any given gun.
You should find that most sabots that perform well in any quality gun with a 1-35 twist should generally do well in your gun.
Those guns would include Savage 210, and Mossberg 695's amongst others.

I have for the most part have shot every high quality sabot on the market out of my Savage 210. (the new Hornady SST being an exception,(It is not expected that it will stabilize well in a 1 turn in 35 barrel, and it iscurrently a special orderitem at most shops)).

While the Copper Solids were one of the top performers, I found two others that that had equivelant accuracy and better ballistics performance.One was the Winchester PartitionGolds.

Even better than the Partitions was the Remington Core Lokt Ultra's. Not only are they extremely accurate, they also have one of the flattest trajectories on the market.

This will not guarantee that they will shoot great in your gun. However it would be foolish not to give them a try!