What is AMO Length?

Categorized as Glossary
What is AMO Length

AMO, an acronym for Archery Manufacturers and Merchants Organization, is a standard set of measurements and specifications developed by the organization to help maintain consistency in bow and string manufacturing.

The AMO length is the standardized measurement of a bow’s string length, which is important for accuracy, comfort, and overall performance.

Relationship Between Bow’s AMO length and Actual String Length

When selecting a bowstring, it is essential to understand the relationship between the bow’s AMO length and the actual string length. As a rule of thumb, the actual string length is typically 3-4 inches shorter than the AMO length.

This is because the AMO length includes extra space for the string’s loops, twists, and stretch when installed on the bow. For example, if you have a bow with a 60-inch AMO length, the appropriate string length would be approximately 56-57 inches.

Factors Affection Your Bow’s AMO Length

Knowing your bow’s AMO length is not only necessary for choosing the correct string length but also for determining the ideal draw length, brace height, and limb alignment. These factors play a significant role in an archer’s shooting form, accuracy, and overall performance.

Drew Length

The draw length is the distance from the bowstring’s nocking point (where the arrow rests) to the pivot point of the bow grip when the bow is at full draw.

AMO draw length is measured in inches and is typically based on the archer’s arm span divided by 2.5. Knowing your bow’s AMO length can help you find a suitable draw length that will enable you to shoot comfortably and accurately.

Brace Height

Brace height, also known as the “fistmele,” is the distance between the bow’s grip and the bowstring when the bow is at rest. The optimal brace height varies depending on the type of bow and the AMO length.

A longer AMO length usually results in a higher brace height, providing more room for the archer’s hand and promoting a smoother release of the arrow.

Limb Alignment

Limb alignment is another critical aspect affected by the bow’s AMO length. When the bow limbs are correctly aligned, the string will rest in the center of both limb tips, ensuring proper energy transfer and arrow flight.

Proper limb alignment is necessary for consistent, accurate shots, and it can be adjusted using a bow press and specific tuning techniques.


In summary, the AMO length is an essential measurement in archery, as it directly impacts various aspects of the shooting process, such as string length, draw length, brace height, and limb alignment.

Knowing your bow’s AMO length can help you find the right equipment and fine-tune your shooting form, leading to better accuracy and overall performance in the sport.

Whether you are a beginner or an experienced archer, understanding and applying the principles of AMO length will undoubtedly enhance your archery experience.