Your gun will shoot 3" groups at 25 yards. Not "tack driver" accurate but good enough to knock down an attacker, just what it was made for. Many older guns are not as accurate as the new ones being produced today, because of the oversized throats and inconsistencies from one bore to another.
To make it shoot better, you will need to shoot oversized lead bullets.
To make it shoot better, you will need to shoot oversized lead bullets.