Shotgun Bead Thread Reference

We've been selling shotgun sights for years, and one thing that always frustrates customers is the lack of standardization when it comes to shotgun bead thread specifications.  We decided to compile this reference page to help our customers find a replacement shotgun bead that works the first time.  

Looking for width specifications for your shotgun's rib?  Check out our shotgun rib width reference page.

Finding the correct front bead thread is important when replacing a factory shotgun bead with an aftermarket sight. Shotgun front bead threads are not standardized across manufacturers, and the thread can vary between models, configurations, and production years. Some shotguns also use press-fit beads rather than threaded beads.

This reference table provides front bead thread information for specific shotgun models and model families based on manufacturer-published specifications and other reference information. It is intended to help you identify the thread used by your shotgun before purchasing a replacement front bead or shotgun sight.

How to use this table:

• Manufacturer: Identifies the shotgun manufacturer, such as Browning, Beretta, Benelli, Mossberg, Remington, or Winchester.
• Model: Identifies the specific shotgun model or model family associated with the listed thread specification. When a manufacturer has used different bead threads across its lineup, individual models are listed separately rather than assigning one thread size to the entire manufacturer.
• Front Bead Thread: Identifies the thread specification used for the front bead. Specifications such as 6-48 and 3-56 are inch-based thread sizes, while specifications such as M3 × 0.5 and M2.6 × 0.45 are metric. Press-fit indicates that the bead is not threaded into the barrel or rib.

When more than one thread specification is shown for a model, this indicates that multiple configurations or reference sources have identified different bead specifications for that model. Do not assume that either specification will fit your individual shotgun without verification.

Important: Front bead thread specifications can vary by shotgun model, production year, configuration, and individual firearm. Some models have been documented with more than one thread specification, while others use press-fit rather than threaded front beads. The information in this table is based on manufacturer-published specifications and other reference information and is provided as a general guide only. Always verify the thread specification and bead configuration of your specific shotgun before purchasing a replacement front bead or sight.

Shotgun Bead Sight Thread FAQ

How do I know what thread size my shotgun bead uses?

The most reliable way is to identify the exact shotgun model, gauge, and production configuration and compare it with a verified bead-thread specification. If that information is unavailable, remove the existing bead and measure its thread diameter and pitch with a thread gauge or caliper. Do not assume that all shotguns from the same manufacturer use the same thread.

How do I measure the thread on a shotgun bead?

Measure the outside diameter of the threaded portion with a caliper, then determine the thread pitch using a thread-pitch gauge. For fractional threads, pitch is expressed as threads per inch (TPI), while metric threads are identified by diameter and pitch in millimeters. For example, 3-56 means approximately 0.0995 inches in diameter with 56 threads per inch.

Are shotgun bead threads standardized?

No. Shotgun bead threads are not governed by one universal standard. Common sizes include 3-56, 5-40, 6-48 and several metric sizes, but the correct thread depends on the shotgun's manufacturer, model, gauge, and sometimes production year or barrel configuration.

Does shotgun bead thread size vary by manufacturer and model?

Yes. Different manufacturers can use different thread standards, and different models from the same manufacturer may also use different bead threads. Some model families have changed bead specifications over time, so the exact shotgun configuration should be verified whenever possible.

Does shotgun bead thread size vary by gauge or production year?

It can. A manufacturer may use different bead dimensions on 12-, 20-, 28- or .410-gauge versions of a shotgun, and older and newer versions of the same model may not always use identical beads. Gauge alone should therefore not be used to determine thread size.

What is the difference between 3-56 and metric shotgun bead threads?

3-56 is an American Unified-style thread designation: approximately 0.0995 inches in major diameter with 56 threads per inch. A metric thread such as M2.5 × 0.45 has a nominal 2.5 mm diameter and a 0.45 mm thread pitch. These threads are different and should not be considered interchangeable simply because their diameters are similar.

Can I replace a pressed-in shotgun bead with a threaded bead?

Sometimes, but not as a direct replacement. A pressed-in bead is retained by its shank rather than barrel threads. Installing a threaded bead generally requires the barrel to be properly drilled and tapped for the new thread. This is best performed by a qualified gunsmith because improper drilling or tapping can damage the barrel or produce an improperly aligned sight.

Can I use a shotgun bead with a different thread size?

No, not without modifying the barrel to accept the new thread. A bead with a similar-looking diameter but a different pitch can cross-thread or damage the existing threads. Never force a replacement bead into a hole with a different thread specification.

What should I do if my replacement shotgun bead doesn't fit?

Stop installation rather than forcing it. Verify the bead's thread diameter and pitch and compare them with the specifications for your exact shotgun. Also check whether the original bead is threaded or pressed in. If the specifications remain uncertain, have the barrel and original bead inspected by a qualified gunsmith.

Can changing the shotgun bead affect point of impact?

Yes. A replacement bead with a different height can change the relationship between your eye, the bead, and the barrel, potentially changing the point of impact when the shotgun is deliberately aimed. The effect depends on the shotgun, bead height, sight picture, and shooting distance. Always pattern the shotgun with the ammunition you intend to use after changing a sight.

How do I remove a threaded shotgun bead?

Threaded beads are generally removed by carefully turning the bead counterclockwise with the appropriate bead-sight tool or properly fitting screwdriver. Avoid using excessive force or tools that can damage the bead or barrel. If the bead is seized, damaged, or difficult to identify as threaded, a gunsmith should handle the removal.

How do I choose the correct replacement shotgun bead for my shotgun?

Start with the exact manufacturer, model, gauge, and production configuration. Verify whether the original bead is threaded or pressed in, then match both the bead's thread diameter and thread pitch. Also check the replacement bead's height, diameter, and intended application. If the exact thread cannot be verified, measure the original bead or consult a qualified gunsmith before ordering.