Just for the heck of it I searched the internet for info on shotshell reloading and 209 primers. The only true magnum primers are the CCI 209M and Fed 209M. The WW 209 is not designated as a magnum primer but it is used in magnum shotshell loads and is right behind the other two in brisance (how hot they fire).
These three are a step above every other shotshell primer.
The reason I looked into this is primer fit and blowback associated with different manufacturer's primer dimensions. I started seeing a very slight amount of blowback using BH209 with CCI209M's in my Omega and I've read reports on the net relating to this issue. I'd never experienced that using 777 with WW209777 primers. It leads me to believe that there might be something to it.
I've got CCI209M, FED209M and WW209 primers to test although I haven't tried all of them yet to see if it makes any difference in blowback or accuracy. The TC Omega breechplug is one of the most BH209 friendly designs so I'm not too worried about using any of the three primers mentioned. I just need to get off my butt and go shooting.
TIFIW.