Alrighty. I dug out my September issue of Barrel Horse News.
This is my favorite line of the whole article: "Attempting to save a horse's mouth by under bridling is hogwash because using a bit that the horse can push on and ignore just programs him to become evasive."
Off topic, but it's still my favorite line.
Gag bits are used to lift the shoulders and encourage vertical and lateral flexion. Gags work on the corners of a horse's mouth by slipping upward.
A shank will give you more rate. A longer purchase will have more lift. Shanks that have more bend or curve encourage flex, versus a more straight shank.
A straight bar off of the purchase of the bit can help keep a horse more square going into a barrel turn.
Combination bits are good for horses with too much bend or young horses just learning to help their frame through a run. The lower the noseband, the more nose pressure.
But horses can get pushy in a gag bit, and often times other aids like a German martingale can be used to times to keep a horse responding well in a gag.
As far as regular curb bits (no gag), low leverage (short shanks) gives you more lift in the shoulders and high leverage (long shanks) gives you more rate.
Soooooooo, based on that article, they're saying that gag bits are much more for lifting. Not that you can't get lift from a short shank curb bit, but that lift is better from a gag. And of course, leverage is based on the shank to purchase ratio.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.