laea7777, I sent you over here hoping someone would answer your question. I see it hasn't happened. So I'll take a stab at it.
What I have read on the inlines that use the 209 ignition system is; you have to use a low powered 209 primer. The theory is that the higher powered primers can actually kick the whole charge, bullet and all forward before it ignites the powder/ pellet(s). I have no personal experience, just what I "have heard". My Ruger inline uses either #11 or musket caps. The TC primers you found are probably a special low powered primer that will ignite the powder, but not be strong enough to unseat the charge.
Remington made a special low powered primer for the .410 shotguns, designated the 209-4. It was made for the same reason as the recommended low powered primers for inlines. Standard force primers would kick the light payloads of the .410 down the bore before the small charge of slow powder could ignite. I suspect the "special" inline 209's are the same as the 209-4.