Just for fun I did a little testing of my V3 TAC-13 and 870 SBS at 100 with a few of my slug loads.  The V3 Tac13 14" SBS (Improved Cylinder) with a Trijicon RMR Type 2 on top and zeroed at 25 yards could print a pretty good group at 100.  I was using the Remington Reduced Recoil Slugger load (RR12RSB).

I was expecting a drop at 100, so I held over and aimed at the head.  Center-punched it on my first shot!  The other 2 in the 3 shot group were a little off to the right, but that might have been me.  



In any event, center mass would have been all in the zero.  Not sure of the ballistics at 100 but I wouldn't want to feel it.

I was also testing my 870 14" SBS (Modified), again with a Trijicon RMR Type 2 on top and zeroed at 25 yards.  I had a few other loads with me and mixed up the reduced recoil loads and full power loads, so I don't have a good read on the groups, but they were nowhere near as good; kinda bad actually (6+ MOA). I am going back soon and will test with a bit more structure.

My 2 primary defensive loads (I know, not planning on shooting these at 100 yards) are the Remington Reduced Recoil Slugger (RR12RSB) and the Federal Law Enforcement 12 Gauge Ammo 2-3/4" Tactical TruBall Rifled Slug Low Recoil (LEB127LRS).  Generally speaking, I've had better accuracy with the RR loads  (1200-1300fps) vs. the full power loads (1600 fps), and the follow up shots are of course easier.

I'll also be testing these in the V3 and 870 soon just for fun; the Federal Shortys (SH129 RS), still 1 oz at 1200 fps (same as Remy load).  They will cycle the V3, but not load correctly so they are a single shot affair; the 870 can run them without trouble (8+1!).

Again, just for fun, to see what I can do with the SBSs at distance with a red dot.

Cool post OP.

Nice first shot. I look forward to hearing more. I have 14" SBS Mossberg, which is one of my favorite guns to shoot.