For the most part you will find that the maximum blade length of "tactical" folders is limited by state and local laws. Knife companies try to sell to the largest audience, so you will find that most tactical folders fall in the just under 4" category. Depending on your locale, you may even be limited to 3.5 or even just 3 inches.
There are other valid (non-legal) reasons for this size:
1. comfortable pocket or IWB carry
2. lock strength -- the longer the knife and blade, the greater the leverage that you can exert on the lock. With even the strongest locks an over 4" blade can become inherently unsafe to the user. According to the President of Spyderco, this is the primary reason why they won't make a folder with a blade over 4 inches.
My daily carry "tactial" folder is a Spyderco Tim Wenger. It has a 3 3/4 inch blade which I find is big enough for most cutting chores, and small enough when closed to be discreet. While there is no length limit where I live, or where Bob lives, there is always the issue of crossing state lines, or even hidden local ordinances in some cities or counties.
Another example of the legal influence on blade length is a new knife designed by FMA instructor Bram Frank. Its blade is just 2 7/8 inches long -- intentionally limited for legal carry almost everywhere in the world. See pic below:
Posted on Sep 5, 2000, 2:27 AM from IP address 220.127.116.11