EndeavorShooter
Cons: The FED209A is unbelievably tight in the breachplug of the Mountaineer.
If you are interested you can send that plug to Lehigh and get a modfication of the primer pocket completed or you can send it here and I can do it. And just a FYI all newer Lehigh/Knight breechplug primer pockets have been programmed to be opened to allow use of a wider range of primers.
+ they have added another hardening process to the surface of the plug for the 2012 offering.