Need some flintlock help

[Mr. 16 gauge]

O.K., I've had this Pedersoli trade musket for a few years now, and I've taken it to the range and practiced with it. However, I have NEVER been able to get more than 6 shots with it before the flint will no longer spark. Lately, at the range the most I get is 3-5 shots, which I find a bit disconcerting because from what I've read everybody else is getting 20+ shots before their flint quits sparking.

Today I took the gun squirrel hunting again, and this time I missed no less that FOUR squirrels because every time I tried to shoot it, it wouldn't spark.....and this is even after changing flints! I tried 3 times on one squirrel alone, without success.

I'm frustrated to the point that I am ready to throw this damn gun into the lake....or at least trade it for a percussion gun. Those I KNOW how to make go boom!

What am I doing wrong? I've knapped and ground the flints down since I shot them last; I've tried various flints (English & amber flints); I've tried bevel up....bevel down....nothing seems to make a difference; THE GUN DOESN'T WANT TO FIRE.

Could it be a frizzen problem? Could the frizzen be too soft (or to hard)?

I wanted to hunt with a historical weapon, but I don't get that many chances to go out hunting, and to lose 4 squirrels in one outing is quite a bit bothersome....I'm glad I wasn't deer hunting with it, or the gun would still be out in the woods wrapped around a damn tree!

Please help me solve this problem if you can

Thanks in advance.........