Hey, yes my email is current and correct. If you have any difficulties you can also email them to me at Radcliff96@netzero.net (This email is actually my preferred).
I've not heard of the R870 Mk1. Sounds like another interesting twist. I should have realized that the 7188 would be similar to the 1100. The 11-87 didn't come along until the late 80s (87?), I guess.
I've not heard that the 1100 was finicky with fouling or particular loads. I had one fella tell me to stay away from the 11-87 as it was more prone to jamming than the 1100.
However, my firearms instructors (former Orange Gunsite instructors)thought the 11-87 would do just fine. I seriously considered simply buying a magnum 870 and heavily modifying it. However, I've had enough nightmare experiences w/ smiths working on pistols (most aren't worthy of the title).
I thought it over and said "screw it." Bought the 11-87 which is almost exactly the way I want it out of the box. The very first shell out the barrel was sluggish on ejection. After that though, Watch Out!!
I think its plenty light, short and very handy. I was surprised with how well it grouped with that IC. This 11-87 is a keeper.