Junnie, There is no rule against use of the 1/2 oz .410 in any 12, 20, or 28 ga NSCA or NSSA event. I'm sure you know this and are jesting. I haven't tried a 42 in a main event, but have used M-12 16s, and various 20s......mostly with 3/4 oz weenies.

I don't imagine you could enter your 42 in a SxS event.

Solid ribs are my favorite 42s, although the VR repros make really steady range guns (and ideal candidates for choke tubes).

But, no, it is not possible to have too many 42s. cool

Sam