Using a 930SPX for trap/skeet?

The barrel should work. Only thing i could see it not working with is the extension. You should be able to un screw the extension and the barrel should slide right on and the only thing you should need is a cap to screw onto the stock magazine tube. As far as the spring im not sure if they use a longer one on those or a stock one and the extension has its own.

Do the rules of your league require you to reduce capacity? I shoot with a few guys that shoot semi-autos and they just load one or two shotshells, depending on whether we're shooting singles or doubles.28" barrel should work. AFAIK, the 930 receivers are all the same.

I did. You will need to take off the ghost ring, or the entire rail. It just depends on your shooting style, and the POA/POI.

I actually bought a 28". Then I had it cut to 24", forcing cone lengthened/polished, threaded for chokes, and f/o bead installed. It works great for trap and 3-gun.

The old farts don't like the tactical-ness of it, but I refuse to spend obscene amounts of money on an OU or a trap specific automatic.

You may not need to replace the standard mag tube. Some clubs say you aren't allowed to increase the capacity, but that is your stock capacity. I have a nordic +5 on mine too, so I have to take it and the red dot off to go shoot at our trap range(s).