Choosing the right optic setup for your firearm is crucial for accuracy and speed. One popular configuration, particularly among AR-15 users, is the 1/3 lower co-witness (1/3 cowitness). This guide will break down what 1/3 lower co-witness means, its advantages and disadvantages, and help you determine if it's the right setup for you.
What is 1/3 Lower Co-Witness?
"Co-witness" refers to the relationship between your iron sights and your optic. A 1/3 lower co-witness means that when you look through your optic, you see approximately one-third of your front sight post below the bottom edge of your optic's window. The remaining two-thirds of the front sight post are obscured. This setup provides a backup sighting system in case your optic malfunctions or runs out of battery.
Advantages of a 1/3 Lower Co-Witness Setup
- Backup Iron Sights: The primary advantage is the readily available backup iron sights. If your optic fails, you still have a reliable aiming solution.
- Fast Target Acquisition: The partial visibility of the front sight post allows for quicker target acquisition in some scenarios, especially transitions between close and medium-range engagements. It provides a familiar reference point.
- Improved Situational Awareness: Maintaining partial visibility of your front sight can subtly improve your situational awareness by offering a glimpse of your surroundings even while focusing through the optic.
- Reduced Eye Strain: For some shooters, the partial sight picture can be less stressful on the eyes compared to a full co-witness or absolute co-witness.
Disadvantages of a 1/3 Lower Co-Witness Setup
- Slightly Higher Optic Mount: Achieving a 1/3 lower co-witness requires a slightly higher mount than an absolute co-witness, potentially impacting cheek weld and overall comfort.
- Less Sight Picture Clarity: The partially obscured front sight can slightly reduce the overall clarity of your aiming point, especially in low-light conditions.
- Not Ideal for All Optics: The 1/3 lower co-witness is best suited for certain optics and may not be possible or desirable with all types of red dot sights or magnifiers.
Choosing the Right Setup: 1/3 Lower vs. Absolute Co-Witness
The choice between a 1/3 lower co-witness and an absolute co-witness (where the iron sights are fully visible through the optic) depends on individual shooting style and preferences.
- 1/3 Lower: Preferred by many for its backup sight capability and quicker target acquisition, especially in dynamic shooting situations.
- Absolute Co-Witness: Provides a clearer sight picture but potentially requires more time to transition to iron sights if the primary optic fails.
Ultimately, the best approach is to experiment and find what works best for you. Consider factors such as your shooting style, the type of optic you are using, and the intended use of your firearm.
Mounting Your Optic for a 1/3 Lower Co-Witness
Proper mounting is key. You'll need to use a specific height optic mount to achieve the desired 1/3 lower co-witness. This height will vary depending on your optic and the type of firearm you’re using. Measuring and testing are vital for optimal performance.
Remember, safety is paramount. Always handle firearms responsibly and follow proper safety procedures when installing and using optics. Consult your firearm's owner's manual and seek professional guidance if needed.
Choosing the right co-witness configuration is a personalized process. This information should help you make an informed decision. Happy shooting!
