Just for another perspective on the TC patent breech...
I have a houseful of them in percussion, flintlock, multiple calibers, standard barrels, round ball barrels, etc...I shoot one of them almost every weekend year round, never have any problems with them.
If the problem you described is in fact associated with the patent breech, it may be that your's has a problem with it or something, but it is not a purvasive problem of TC patent breeches...on the contrary, they prevent fouling / clogging in the breech area that is often heard about with straight breeches plugs getting fouled due to patches pushing crud down around the vent. My typical range session is 40 shots a trip and no matter which TC Hawken I take, and there are no problems like that...they're as reliable as shooting a .30-30.
Also, you can routinely pick up mint condition used TC Hawkens or Renegades in the $225-275 range.