Not even knowing the action type, my suggestion is to clean it out by filling with sand and shaking vigorously.
Now, if it is a non-semiauto (bolt/lever/single) you can probably get away with a swab through the barrel and checking for (and removing if needed) grit in the action.
For a semiauto, there will be powder residue in the action to remove to some degree or another.
For anything you ran dirty ammo through, apply more cleaning.
For clean ammo, apply less cleaning.