Hello Jason!
The main advantage of the short arc straight punch is that the power flow continues right through the target. The idea is to increase the power of the punch by giving the punch "follow through" as in the swing of a baseball bat or a golf club, rather than the straight out, straight back motion of the normal jab or straight punch.
The punch starts off looking just like a normal vertical fist lead straight punch. You turn your waist and hips into it and push/pivot from the raised rear heel position, penetrating the target with maximum force and as your arm fully extends, rather than stop for a split second and return on the same path, continue your motion by arcing slightly inward and just through the centerline. Using this arc of continuous motion, you can return immediately to your on guard position. In other words, once the punching movement starts, it doesn't stop until you have recovered to your on guard!
Now, make sure that you are using a short arc rather than a long arc. The long arc is a powerful blow also, but is only used when executing a "finishing move" at the end of a combination of strikes! The long arc takes more recovery time and exposes your centerline for a brief moment.
I have used the shortened arc principle, combined with the principle of concurring and overlapping circles, to double a students punching power in a single private lesson! IT WORKS!

Keep Blasting!
Sifu Lamar M. Davis II
Senior Instructor
Hardcore Jeet Kune Do
Sifu@HardcoreJKD.com
JKD@windstream.net
http://www.HardcoreJKD.com
http://www.DragonBlastMA.com
Phone (205) 296-7070 (Incoming Only)
"Hit Hard, Hit Fast, Hit First - ALWAYS!"
"The REAL future of Jeet Kune Do belongs to US, the few, the proud, the HARDCORE! Now, what are we going to do with it?" _ Sifu Lamar M. Davis II