"... Also have Remington M48 and a Savage SxS in 16, so the MEC does get some use.
Wads are hard to find though.
Holy smokes, the last time I saw 16s in factory loads, they were $15 a box! ...:

I have a Rem "Sportsman", two Win M12's, a Steven's and an "Elsie", all in 16 gauge.

I constantly keep my eyes peeled for 16 gauge ammo - ANY loading!

We "snow bird" in south Texas every winter.
Found 16 gauge ammo in a feed store in Falfurrias, TX.
Found ammo at a old M&P gun store in Bishop, TX.
Academy at Corpus Christi nearly always has a few boxes of 16. It's all a bit pricey, but I scrap my pennies together and buy a box or two along.....but I don't shoot a lot either. Kids ought to have a pretty good store of ammo by the time I'm gone! 😉