I'm not sure that I understand your question.
Normally, if the bullet is a wee bit too long, one just seats it more deeply into the case. Modern smokeless powders take up relatively little room, making this easy.
Normally, shorter bullets can be less accurate, depending upon the ratio of length to diameter. The ratio you seek may lead to inaccuracy.
Normally, the heavier bullet produces the better terminal ballistics.
Normally, pistol bullets are chosen solely for their weight, and their length is accommodated within the case. For the .380, anything from 90 grains to 110 grains should be useful.
What is the groove diameter of your barrel?
Why do you specify a short bullet?
Why isn't bullet weight important?