The Snaffle Bit.
Every horse owner has one or has used one at one point in time, and it is widely (and blindly) accepted as the softest and most humane bit available.
In the book "A Whole Bit Better" By Dale, Ron, and Bob Myler a snaffle is described as a ring bit, "The rings may be round, oval, or shaped like a "D." A loose ring allows the mouthpiece to rotate around the ring; a fixed ring does not. Both the headstall and the reins are attached to the ring. When pressure is exerted through the reins, the bit pulls with the same amount of pressure backward on the horse's mouth; thus a ring bit is often called a direct action bit."
Simply put true snaffle bits are direct action, non leverage bits.
Meaning that pound for pound your horse feels the exact amount of force you use.
A snaffle is only a snaffle when the mouthpiece, reins, and bridle are all attached to to the same ring.
A snaffle bit may have any type of mouthpiece.
All of these bits are snaffle bits because the mouthpiece, bridle, and reins all attach to the same ring.
Just because a bit is called a snaffle does not mean that it is humane.
Direct Rein Bits work by contacting the palate, bars, tongue, and lips.
The mouthpiece and the amount of pressure used by the rider determines the severity of a snaffle or direct rein/action bit.
A straight mouthpiece can create a nutcracker effect on the tongue and bars.
While a more curved mouthpiece will not immobilize the tongue.
Which would you put in your own mouth?
I have used 1, 3, and 4, based on each individual horse's preferences, but never number 2.
In closing a snaffle is a direct rein bit.
A snaffle is only a snaffle if the mouthpiece, bridle, and reins are attached on the same ring.
The severity of a snaffle bit is determined by it's fit, construction, and amount of tongue relief provided.
A straight bar mouthpiece like number 2 (disregard the twist, looking only at the straightness of the mouthpiece) is more severe 1, 3, and 4.
Bit number 3 is more severe than bits 1 and 4 due to the amount of tongue relief available.
A twisted mouthpiece is more severe than a smooth mouthpiece.
A smooth twisted mouthpiece is less severe than a square, or fishback twisted mouthpiece.
The thinner the mouthpiece the more severe.
Stay tuned for Curb/Leverage Bits coming soon.