Nothing. I can't tell a difference between my B11 and my B9 in edge performance or rust resistance. Could be the same steel for how well they both work.
I think Modified INFI was created as the gateway drug with the (then) cheaper basics... once you get a taste you think "Mmmm... INFI" and you are hooked, forever buying much more expensive pieces.
INFI was being used in the Busse line (SHBM, SHSHII, and others) when M-INFI was introduced in the original Basic series (B3, B5, B7, B9) the Basics were less expensive than comparable INFI models. If I remember correctly, the supply of M-INFI ran out, and it would have been too costly to replace it, so that was about when Swamp Rat came into existence to offer a lower-cost alternative to INFI.
Someone correct me if I am wrong but weren't the basics from this past Blade 2012 Infi not M-Infi? I was told that my all sage Basic 9 is Infi not M-infi. But it also has a 10" blade and oal 15 1/8".
You are correct the sage Basic 7's & 9's from Blade 2012 are INFI. Production ceased on the original Basics in about 2001. I bought my first Busse, a Basic 9, in late 2001 before the supply dried up (the Basics were available from many internet knife dealers back then). All of the original Basics have black handles, and most have black blades (I remember seeing a photo of an early satin Basic on a sales flyer). The earliest Basics have a smooth finish on the blades, and the later ones have the crinkle finish (same as the SHBM and other models).
). The tip profiles are different on the Basic 9 & 10.
