A good suggestion, reloader28; but I'd say it would be a good idea to slug it, regardless of bullet choice.
The aforementioned 'finicky' .380 that I fought with ended up having a .358" x .359" (oval) barrel at the chamber and muzzle ends, but was even larger in the middle -- somewhere beyond .360". (Manufactured that way -- not a bulge from 'Bubba'.)
Even though all of the armchair quarterbacks 'knew' the thick skirt of the Berry's 100 gr HBRN wouldn't expand to seal the bore in that barrel, and I had my own doubts about it, it turned out to work perfectly.
With jacketed bullets, it was plainly evident that bullets were skipping across the middle of the bore when fired. But with the 100 gr HBRNs, they made contact the whole way through. The skirt 'rode' the walls, maintained a good seal, and improved accuracy greatly.