A backspinning round projectile would have terrible ballistics compared to a conical projectile spinning on its long axis.
Even in paintball its not really an advantage. Backspinning has been around since about 1990, and has gone through various trends since then. Once the gimmick wears off, the negatives usually irritate the user enough swap out to a traditional system.
And for the case of firearm, you would reduce your effective range by probobly 10 fold, for the advanage of a slight curve around a corner? Thats crazy.
However, that said, backspin systems have always been very popular ith airsoft. Its the one place where you don't see much of the problems associated with backspinning paintballs.
__________________ www.montneel.com "the evidence strongly suggests that neither Billy nor Adam (Smart Parts) could have invented the electronic paintgun" -Garr M. King, U.S. Judge