In order to find the most suitable bit for your horse, you need to go through a process of elimination.
Ideally every horse should have an annual check up.Sometimes it is necessary for the equine dentist to remove wolf teeth or Tushes as they can cause biting problems.
Have you looked inside the horse’s mouth to access the mouth conformation?
Have you checked the horse’s mouth for cuts, bruises or ulcers?
Based on this information you are now able to make a decision with the information you have.
Does the bit fit correctly in the mouth?
If the bit is too big or wide in the mouth, it will slide back and forth when turning, potentially cause rubbing.
A ported bit that is too big in the mouth will also slide back and forth, therefore will not remain central on the tongue.

The bit measurement is taken from the inner sides of the bit rings or cheeks with the bit lying flat.
Standard size bits range from 3 ½ inches (9cm) to 6 inches (15cm) and go up in ¼ inch to ½ inch steps.

Lack of salivation is the sign of an insensitive mouth and the horse is often very strong.
A dry mouth will also cause the corners of the lips to rub due to surface friction.
A horse must be encouraged to lightly salivate as saliva acts as a lubricant. 

if a horse feels discomfort in his mouth he may tolerate it for so long.
As the pressure begins to build up the horse will try to find a way to evade the discomfort and be able to free himself.
There are many bits available designed to encourage salivation.
High copper content, equine bits are known to be effective.When a bit is in the horse’s mouth it applies pressure to the bars of the mouth. 
The bars are a sensitive area and some horses can be over sensitive. (The gaps between his front and back teeth are known as the bars, on either side of the jaw). 

 Most horses are started off in a snaffle bit, and some never need to wear another bit.
The snaffle bit has more movement in the mouth, often known as a “nut cracker action”.
The bit works on the corners of the lips and bars of the mouth.
Not all horses like the “nutcracker action” and will display this by lifting their head higher when you take contact.
There are many variations of the snaffle with some snaffles being quite harsh.
Your horse will let you know what bit is right for him.

A straight bar or Mullen mouth has no joints and works best on the bars of the mouth and lips.
If the horse has a large tongue this increases the tongue pressure and can be uncomfortable for some horses.
If the horse has a small tongue this type of bit would exert more pressure on the bars

French Links have no “nutcracker” action and two joints with two arms and a link in the middle.The French link has proven one of the most popular mouthpieces; it has 2 joints, which means the pressure of the bit is distributed over both the tongue and bars of the mouth. Because the mouthpiece has two joints, it shouldn’t cause any interference with the roof of the mouth. The French link uses tongue pressure to encourage the horse to go on the bit and has bar and lip pressure but not a ’squeezing’ action like that of a bit with a single joint. The more joints a bit has the less likely the horse is to lean as the bit becomes more mobile.

The magic mouth is a very mild mouthpiece; it is an unvarying mouthpiece, which means the pressure on the mouth doesn’t change very much, as it is a fixed mouthpiece. This mouthpiece is super alternative to the straight bar for horses with a larger tongue, horses that are likely to have larger tongues are for e.g., Irish Draft x or the Dutch Warmblood. The bit puts pressure on the tongue and lips (corner of the mouth), it does use slight pressure on the bars depending on the size of your horses tongue, more than that of a Mullen mouth. This bit is very useful for those horses that have a very soft mouth and don’t like complicated mouthpieces, it may also be useful for horses that back off the contact and need that extra bit of confidence in the bit. 

This waterford has a chain type mouthpiece which has ‘ball shaped links’ linked together, the bit is floppy and mobile in everyway, it is completely movable in all directions. The Waterford mouthpiece has proved one of the most popular bits for bitting problems such as leaning, taking hold of the bit, setting the jaw ect, when the horse tries to lean or take hold of the bit, the waterford mouthpiece collapses, thus the horse has nothing rigid to take hold of. It encourages the horse to work of their quarters and carry themselves rather than using the bit as a ‘bike handle’ to lean on. This bit has several joints and distributes the pressure of the mouthpiece over both the tongue and bars. Also this bit may look severe, this is quite a mild bit and due to the mobility of the mouthpiece it generally suits any breed of horse and mouth confirmation.

The Magennis has small copper rollers set into the mouth piece, which are designed to roll over the jaw to help prevent a horse from crossing and setting its jaw, the copper in the rollers is renown for causing salivation and helping the horse mouth the bit.

.The copper roller mouthpiece incorporates stainless steel and copper rollers, the rollers may help if your horse tends to lean on the bit and or set their jaw, as the rollers are movable so they are not easy to get a grip of. They also encourage mouthing as it gives them something to play with.