My 11-87 is a great gun. The O-ring has never failed, but the feed latch has broken several times while shooting 3 inch steel BBs or #2s. I called Remington and was told not to shoot larger than #4 steel, because the larger pellets create too much back pressure. They had no reason why this information isn't in the owner's manual.
So, I bought a Benelli SBE II for trips away from home. I still shoot #2 steel through the 11-87, but always through an IC choke (not sure if it was a mod choke that was in when the feed latch was breaking).