Dan
As I cant see where you live you may want to check out the BP regs on the use of what you speak of if you intend to use the TC for hunting.
Back when I was a capper as I recall there where lots of different nipple designs for the tried and true #10 and #11 caps. As I recall I had one that was called a hot shot.
For me it was way more consistent then the standard nipple, I also went back to BP from PDx and that helped even more.
Just a thought

the newer primer ignition systems offer significant improvement over the older cap systems. Ignition is more sure and with a lot less lag time...important for hunting. The system is sealed and therefore weatherproof also. I have used them for years, and would not go back to the older cap system

Sorry
If that were the case then I would really look at your hunting rags.
I know here in Idaho they would not be aloud in a BP season.
Never had a cap that was slow and certainly not my flint, they must be real fast
good luck in your search

Our wisconsin hunting regs do not eliminate these, and a great many of the inlines already use such a system.

I found it. It is called the Mag-Spark and is available from hubbards outdoor products at the following website...http://dhwebworld.com/hubbards/mag.html

Mag-Spark
The most innovative improvement to muzzle loading since the rifled barrel. It fits your rifle in the place of the percussion nipple and uses inexpensive, readily available SHOTSHELL PRIMERS for instant ignition of all powders and propellants. No more misfires, slowfires or dangerous hangfires. Works in any weather, with any propellant. Shotshell primers provide abundant fire to burn the propellant charge-completely. EVERY TIME!! This makes for consistent velocities, which makes for tighter groups (Also reduces flinching). Another important feature of the shotshell primer is that it is made with a rim , or flange, making it impossible to be put in upside down or sideways. This is not tru with rifle or pistol primers. If you have ever tried to use them, you already know this. Moreover, rifle and pistil primers stick when fired. Have you ever tried to get one out in time for another shot? Forget it!!. You CAN remove the shotshell primer from the MAG-SPAR, because of the rim feature.
Made of stainless steel, the MAG-SPARK features a hardened firing pin, and is intended to last for a lifetime of normal use. Nothing, not even an expensive in-line rifle can deliver the reliability of a MAG-SPARK equipped rifle. It is FULLY GUARANTEED, INEXPENSIVE, EASY TO INSTALL, LOOKS GOOD ~ AND IT WORKS.

MAG-SPARK $15.00
Spare cap $7.50
Mag-Spark and Spare Cap Combo $22.50