This is not a trivial achievement.

It required the manual dexterity and procedural knowledge of firearms use, applied under the stress of a hunting situation against animals that could kill her.

The practical knowledge of what to do after killing an animal — how to skin it, how to cut and preserve the meat, how to tan or otherwise treat the hide — is also not trivial.

These are skills that take time to learn and that have specific techniques for effectiveness.

Marguerite would have had to figure them out, or learn them from her companions before they died, or improvise successfully enough to make them work.