No need to shoot any of these plugs to know how good they are. The plug on the left is a T/C Impact plug. This plug is amazingly designed. T/C is leading the industry in breech plug making.

The second plug from left to right is the NULA plug. Here again a very good design.

The third is a Lehigh conversion plug. This plug was designed around the Exteme/Elite muzzleloaders. This plug would be more like the plugs on the left if it wasn't designed for a already existing ML.

The plug on the far right is a CVA MR plug for BH209. This plug would be perfectly fine for all powders or pellets if they shortened the plug close to 3/8 just guessing and put a 5/32 flame channel and left the plug flat on the end. A .30 flash hole would be good. This would reliably ignite all powders.

With out a good design there's no sense or need to fire the gun. Once you got a good one, firing is needed to determine cleanliness and head spacing to keep clean.