Using the book "Buffalo Bill's Wild West an American Legend" by R.L. Wilson and Greg Martin, as a reference, If you look at page 131 you will see that Annie was capable of having a very off day.
At Charles Lancaster's private grounds (in London), while shooting at Blue Rock pigeons she hit 5 out of 20. Here is a quote from her about the experience:

"I shot with an American gun all bedecked with gold, showing a gold figure of myself in the guard. The gun was about a three inch drop, not bad at that early date for a target gun, but for those little blue streaks of birds that made for the high stone wall like greased lightning-never.

After I shot at a string of 24 I could have been led home easily by a lingerie robbon."

Soon after she had Lancaster make her a new side by side, six pounds of weight , made to her measurements. She characterized the gun "perfection".

Annie had many guns, American and English, for different uses.