If you do try Blackhorn 209 powder with the CVA get you a 1/8" drill bit, wrap enough Gorilla tape around the shank so you can grip it firmly. Then I like to use the bit after every 3 to 6 shots to clean out carbon that accumulates in the Flash tube (area under where the primer sits). If you don't it will get to the point your breech plug will be filled up with carbon and cause problems with ignition and you will need a electric drill, starting with smaller bits to clear it. One thing to remember is don't apply too much pressure and cut metal from your flash hole area. I like to take the plug when it is new and put the tape at the point on the shank that marks the depth of the breech plug Flash tube, that way you have something to gauge it by.
You don't have do the drill bit thing with other powders.
Personally for cleaning the Flash tube, I use these
http://www.plugcleaner.com/images/Instr ... CH-web.pdf The manufacture does not sell them themselves anymore but CVA has a contract with them and does sell it for their guns, Myself I think it is worth the money but the manufacture use to sell them cheaper. CVA sells the 1/8" unit, I use same size for my Traditions, and T/C muzzleloaders. You will never cut into a flash hole with one, no matter how much pressure you apply.
Measure your breech plug Flash hole, through out the shooting season & occasionally measure it if you shoot a lot. when the size of the hole grows from the new measurement to + .003 or .004 replace it. Otherwise at some point you will start having problems with your rifle grouping, for no apparent reason.
CVA will tell you to use their breech plug grease on the breech plug, many people use different breech lubes or never seize, Myself since 1984 I have used Teflon tape, at first on the cap plugs for caplock guns because they would be hard to get off after shooting, then on breech plugs. If you ever have to dump a load and that powder gets all in the grease it is a mess to clean up. Also I find the breech plugs nasty to clean when using grease or never seize. I have never heard of anyone that used Teflon tape to complain about a stuck breech plug. I use 2 wraps of the white Teflon on a CVA type Breech plug.
Since you shoot Barnes TMZ or TEZ you will need this to keep from damaging the bullet as you load it:
https://www.midsouthshooterssupply.com/ ... ez-aligner
If you shoot pellet powder you can use the original Breech plug. You can use the Blackhorn 209 Breech plug for regular powder supplements, or Blackhorn.
When primarily trying to develop a group with a bullet, my personal opinion is that you will have more options in developing a load with powder supplements. You can vary your powder loads 5 grains at a time up or down to try to get a bullet to group. You can't do that with pellets, maybe start at 90 grains and work up to 110 or 115 grains. When you get a good group, keep adding 5 grains more until your group starts to open up or you reach the maximum charge for the gun, if you like it that hot.
Also you can vary Sabots, the primer and the bullet if necessary to develop your load.
I don't know what you use for cleaning but I use Hopp's Elite Gun Cleaner and Slip 2000 gun lube for all types of guns and all types of black powder substitutes and Modern guns & smokeless powder. I have use these cleaners for years with great success, If you do shoot Blackhorn 209 use cleaners and lubes for smokeless guns, T7 cleaners and such will not cut it.
One last thing when you are developing a load clean your gun between shots, you will get more consistent results. For T7 & such I like to use a solvent patch, dry patch, lube patch, & dry patch. With Blackhorn you do not have to do that, I am a creature of habit and it makes me feel good so I clean between shots with BH 209.
Everyone has their own cleaning regiment if they feel the need to clean between shots, you will probably develop your own if you clean between shots. Shooting t7 you will probably have to clean it every 3 to 4 shots anyway.
