Encore .50 cal firing pin issues

[BubbaNColo]

Got a Encore 209x50 blue, used it for several years.
Was at range and noticed the firing pin tip was broke off, yet gun would still fire.
I took a screw driver and reached in and pushed firing pin forward so I could see how bad it was, the firing pin stuck forward, I had to push it back into action.
After I got home I played with the action and determined the firing pin had lots of black residue coating the pin keeping it from returning into action. I hadn't cleaned the firing pin or cavity ever.
I called S&W (it still doesn't sound right, I was used to that NH accent) and ordered a new firing pin and spring. I cleaned action and assembled.
Firing pin moved in and out of cavity and didn't stick.
I went out and shot the gun only one time. I checked the firing pin again to see if was sticking and it was sticking and again had black residue cooked onto outer surfaces.
I'm using Rem 209 primers.
Does anyone know if there is a spec on how deep the breach plug can be screwed into barrel leaving a gap between 209 primer and breach face of action. I'm thinking there is too much gap allowing primer to jump out of primer pocket enough to leak back into action. Even thou I'm lightly snugging the breach plug after cleaning.
 
This same design is used in most inline rifles I've seen with firing pin inside a cavity with small hole just like you see with a normal non-blackpowder rifle. I can't think the design is bad, it has to be more of a gap issue or maybe a brand of primer....
Any help would be great!

[muznut 54]

Try a Winchester 209 they are longer and should seal better in your gun and some guys use a 1mm by 4.5mm O'ring in their primer pocket. After I'm done shooting and I don't want to pull the pin I use a WD40 spray can with a straw and hose out the pin area from the firing pin hole and that will keep the rust out of that area too.

[BubbaNColo]

Would this oring be placed on the primer itself under the lip, or under the primer nipple itself as a washer?

[muznut 54]

In the breech plug primer pocket and it will last 30 to 50 shots.

[Muddyboots]

A hex head 1/8" drill used by hand to scour out the breech plug primer hole is perfect to keeping it clean, doesn't harm hole since you are just using it remove hard residue by slight finger pressure. I keep one in possibles bag all times for field. Clean regularly at range. Also nipple pick the breech plug hole to charge. Never had any problems once I started this few years back. Saw a chart not to long ago where the Win 209 was the least hottest of 209's which is good for consistent velocity and accuracy and residue build up both in breech plug and that nasty 777 ring in barrel that forms after each shot. Wet patch and dry patch after each shot.
Muddy

[muznut 54]

I use the hex head drill bit too for cleaning the flame channel in the breech plug , you can buy them from Lowe's.

[rookie_615]

Get a allen head wrenc with the action open and hammer back there is a screw on the action where the hammer hits the firing pin..  you can unscrew that and on the inside of your action take the cover of the firing pin off.  Just pay attention to the way the spring is when take the pin out..  try cleaning it real good..  maybe dirty and sticking.. dont know if that helps you or not