I cannot use hard shot like steel or similar, because of possible bore damage.
Just so we're clear on the 3 types I mentioned:
Copper plated and nickel plated are not like steel...they are lead pellets with a coating which does not bother a steel bore...used them in my smoothbore Flintlocks for a few years now.
EcoTungsten is literally a direct lead substitute, can be used in any form of and age of gun without shotcups. In fact, one of the saving graces of EcoTungsten is that is is such an identical soft lead substitue that you can use the corresponding "relatively less expensive" lead pellets for load development & pattern testing.
The just fire a couple of insurance shots with EcoTungsten to satisfy your mind that they do indeed pattern the same way.
