It is your horses responsibility to stay between the reins. If your horse gets heavy in the snaffle, it may be time to upgrade your tools.
Professional quality. Awesome feel. 

Stainless steel ring.  Alloy steel mouth to resist pitting
Options include:

3/8 Ring with 5/16 Mouth and 5/16 Ring with 3/8 Mouth

No Lean Snaffle