So long as the mag extension is properly blocked to 5- 3" rounds, you are fine (this is assuming your shotty can handle 3" and 2 3/4")
I have switched over to the semi just because of shooting strings of 4 and 5 targets I find abit quicker, that and my 930 SPX is lighter than my 590A1 SPX by far.
In the end, I think it all balances out because there is that reloading thing that you need to do. If you buy a handful of 12 gauge snap caps and practice practice practice.
Usually a week or two prior to the event, I'll spend about this drill for an hour or two each night:
Empty tube, one snap cap in chamber
Dry fire, manually cycle the snap cap out
"Combat reload" the chamber (over the top, under etc.) send the bolt forward
Load 4 snap caps in the tube from belt mounted shell carrier (or side saddle, etc.)
Aim and dry fire and manually clear each snap cap until empty.
This trains the muscle memory and technique to: facilitate fast reloads when empty, getting a shell in the chamber quickly when empty, clear an FTF or FTE, and generally make you comfortable handling the shotgun. With a shot timer set to random start, it can help simulate tournament style pressures so you can identify and work on weaknesses.
I still am not good on the reloads at all(using the four shells in the hand method) but I'll practice it when I can as my son is always curious as to what I am up to
I like BBB's DSC's because they do not add alot of weight on the receiver so the balance is not that much more different without. With a metal or plastic one, the balance is noticeably shifted.
Hope this was helpful in some sort of way
