The crud ring is something you have to deal with when using 209 primers and 777 powder. The degree to which you have to deal with it has everything to do with what primer you are using and the design of the breech plug, along with other factors such as humidity/weather/temperature, bullet type/weight, sabot, lubes, cleaning solvents to name a few.
Each muzzleloader is an individual, and you will have to experiment to find out what works best in your rifle to keep the crud ring to a minimum.
What rifle are you using? What granulation of 777, FFG or FFFG?
777 powder is worth the hassle IMO, I just have to find what works best for me in my rifle. 209 ignition is overkill for lighting off 777 loose powder, but is necessary when using 777 pellets. The heat of the primer caramelizes the "sugar based" powder, thus the crud ring. Your best defense is a cooler primer, or better designed breech plug. I use a .25 ACP plug in my Huntsman, and won't ever be going back to 209 primers. All my other muzzleloaders use #11 RWS caps, by design and choice.