Re McKay Brown, it's my understanding they've recently closed shop. Along with Dickson. I haven't seen that verified, so it may not be accurate.
Re Merkel OU's, I'd say they're only "ungainly" if you prefer shallower and wider to deeper and skinnier. There are many companies making OU's that can't match a Merkel for weight, gauge for gauge and barrel length for barrel length. That is, unless they use an alloy receiver. With their slender forends, Merkel OU's handle a bit more like sxs (and lots of used ones out there with double triggers) than do most other OU's. Nice to have those options in the OU world.
