I have always wondered about the removable breech plug on the firestorm. T/C marketed as being able to shoot pellets with the cone shaped plug. I have never shot pellets and don't ever plan on shooting pellets. What I have wondered if it would be advantageous to cut or grind the cone off and the plug would be flat, if this would help with ignition speed?
I don't use pellets just loose powder and don't have problems. I've heard that you can put a few grains of 4f behind pellets to speed up ignition. The problem seems to be igniting the pellets versus loose powder from what I heard.
I apologize. My explanation was not very clear. I don't use pellets. T/C marketed the firestorm and cone plug towards the use of pellets. I believe the idea was pan ignition thru the touch hole and fire around the cone with pellets on top was t/c's theory. My thought (and could be way off here) was that since I don't use pellets, to cut the cone off and possibly be more loose powder friendly. If that makes sense. Sorry for the confusion.
If you grind of the cone, I would assume the powder would sit in a different location in relation to the touch hole. It would probably fire slower as the touch hole would be in the middle of the charge.
Most custom flintlock rifles have flat breech faces. For use with loose black powder, I can't see how it could hurt. For a range session involving many shots and wiping between shots, I think it will be a lot better, and work as well as it does on custom rifles.
Removing the cone will do nothing beneficial in my opinion. The cone lets more sparks in around the base of the pellets is the idea. If you use loose powder, it will just fill in around the cone similar to if there was no cone there. Getting rid of the cone would just allow your powder charge sit a slight hair lower in the breech end. But any future buyer of your Firestorm might not like that the cone was ground off. There may be other breech plugs that fit the Firestorm that would save you the grinding to experiment. I've shot both pellets and loose powder in my Firestorm, and find that a bit of pan powder (4F) tapped into the flash hole from the pan under the pellets helps with a quicker ignition. Loose powder seems to light right now as is. YMMV.