How to Measure the Inner Bore of Your Shotgun

Measuring the inner bore of your shotgun is an essential task for any gun owner or sports shooter. Understanding the dimensions of your shotgun’s bore can help in selecting the right ammunition, maintaining the gun’s accuracy, and ensuring safe shooting practices. In this article, we will discuss the importance of measuring your shotgun’s inner bore and provide a step-by-step guide on how to do it accurately.

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Understanding the Importance of Measuring Your Shotgun’s Inner Bore

The inner bore of a shotgun refers to the diameter of the barrel where the ammunition travels before exiting the gun. Knowing the exact measurement of your shotgun’s inner bore is crucial for choosing the correct size of ammunition. Using the wrong size of ammunition can not only affect the accuracy of your shots but also potentially damage the gun. Additionally, regular measurement of the inner bore can help detect any signs of wear and tear, allowing for timely maintenance to prolong the gun’s lifespan.

bore gauge

Measuring the inner bore of your shotgun is also important for safety reasons. A properly sized bore ensures that the ammunition fits snugly and securely in the barrel, reducing the risk of misfires or other malfunctions. By accurately measuring the inner bore, you can be confident that your shotgun is in good working condition and ready for use during shooting activities. Overall, understanding the dimensions of your shotgun’s inner bore is essential for both performance and safety reasons.

Step-by-Step Guide to Accurately Measure the Inner Bore of Your Shotgun

Here’s how you can measure it:

  1. Gauge or Bore Size: First, determine whether your shotgun is measured in gauge (like 12 gauge, 20 gauge) or bore (like .410 bore). Gauge is a measure of the number of lead balls of bore diameter that equal a pound in weight.

  2. Use a Caliper or Gauge: To measure the actual bore diameter, use a precision caliper or a bore gauge specifically designed for shotguns.

  3. Insert the Tool: Carefully insert the caliper or gauge into the bore of the shotgun. Ensure it’s inserted straight and not at an angle to get an accurate measurement.

  4. Take the Measurement: Once inserted properly, read the measurement on the caliper or gauge. This will give you the diameter of the bore.

  5. Check in Multiple Places: For a more accurate measurement, check the bore diameter in multiple places along its length, especially if the bore is not perfectly cylindrical.

  6. Record the Measurement: Note down the measurement for future reference when selecting ammunition or discussing your shotgun’s specifications.

Start by ensuring the shotgun is unloaded and remove any obstructions from the barrel. Insert the cleaning rod into the barrel from the chamber end until it touches the bore’s wall. Mark the cleaning rod at the point where it exits the barrel.

Next, carefully remove the cleaning rod from the barrel and measure the distance from the tip to the marked point using a measuring tape. This measurement represents the inner bore diameter of your shotgun. It is essential to take multiple measurements at different points along the barrel to account for any variations in bore size. Once you have gathered all the measurements, calculate the average to determine the most accurate inner bore diameter of your shotgun.

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What’s the Best Shotgun Rib For You?

Not all shotgun ribs are created equal, as there are various types of ribs available on the market.

Krieghoff’s K-80 Parcours-X with optional engraving.

Here are some common types of shotgun ribs:

  1. Ventilated Rib: This type of rib has slots or holes along its length, designed to dissipate heat and reduce mirage effects caused by barrel heating.

  2. Solid Rib: A solid, non-vented rib that provides a continuous surface along the top of the barrel, often preferred for its simplicity and sometimes for aesthetic reasons.

  3. Tapered Rib: A rib that tapers from wider at the breech (near the receiver) to narrower at the muzzle, which can affect the handling characteristics and weight distribution of the shotgun.

  4. Flat Rib: A rib that is flat on top, without any additional contouring or shaping. It offers a straightforward sight plane for aiming.

  5. Raised Rib: A rib that is higher than the barrel, providing a more prominent sight picture. Raised ribs are often found on trap and skeet shotguns where precise aiming is crucial.

  6. Parallel Rib: A rib that runs parallel to the bore axis of the barrel, maintaining a consistent sight picture throughout its length.

  7. Stepped Rib: A rib that changes height at certain points along its length, which can sometimes provide a more versatile sighting arrangement.

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Understanding the Differences Between Rib Styles

Each type of shotgun rib has its own set of advantages and disadvantages. Ventilated ribs are popular for their ability to reduce heat mirage and improve target acquisition speed. Solid ribs, on the other hand, are favored for their simplicity and durability. Tapered ribs are known for their versatility, as they can accommodate different shooting styles and preferences. It’s important to consider factors such as shooting discipline, personal preference, and budget when choosing a rib style for your shotgun

Choosing the Right Rib for Your Shotgun Needs

When selecting a shotgun rib, it’s essential to consider your shooting goals and preferences. If you participate in fast-paced shooting sports like trap or skeet, a ventilated rib may be the best choice for improved target acquisition and faster handling. For hunting or field shooting where durability is key, a solid rib might be more suitable. Tapered ribs offer a middle ground for a wide range of shooting activities. Ultimately, the right rib for your shotgun needs will depend on your individual preferences and shooting style.

Whether you prioritize heat dissipation, durability or versatility, there is a rib style that will meet your needs. Remember to consider your shooting discipline, personal preferences, and budget when selecting a shotgun rib to enhance your shooting experience.

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Standing up for Public Lands

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May 9, 2025 by Ruffed Grouse Society — Last week the U.S. House of Representatives Natural Resources Committee passed a budget bill ordering the sale of thousands of acres of public lands in Utah and Nevada.

Using a budget bill is an unacceptable departure from the proper means of evaluating land transactions. Existing laws for sale or exchange of public lands require due process and the return of revenue to the public land system. A budget bill meets neither requirement, preventing evaluation and diverting revenue to the Treasury.

RGS & AWS is joining many partners in advocating the removal of the land sale provisions from the forthcoming budget bill on the House floor. Before a budget bill is enacted, it must also be approved by the Senate. The process could take several weeks or longer.

At RGS & AWS, our commitment to conserving wildlife habitat is simultaneous with keeping public lands secure. This reflects our community’s values – and is a message we underscore with our elected leaders as they weigh decisions about public lands policy. That guides our work in Washington, D.C., where we engage on a bipartisan basis to increase public access – not reduce it – and enhance conservation value, not lose it.

The House budget bill further complicates this equation. Since the amendment was advanced through the budget reconciliation process, the revenue raised from the sale of these public lands goes to the general Treasury fund. It would not be reinvested in public lands, as is standard practice for public lands sales, via the Federal Land Disposal Account, a Treasury account used by federal departments to purchase other lands, especially those with high conservation, recreation and/or public access value.

A budget reconciliation bill is not the right place to legislate public lands sales. Fundamentally, these proposals should include ample opportunity for public consideration and feedback. And they must be advanced via agency action or congressional authorization to keep the money raised from their sale within our public lands system.

If you value our public lands and waters, we ask you to make your views known to your elected leaders in Congress. Take a moment today to express your strong opposition to the House budget amendment mandating the sale of public lands. Call the U.S. Capitol switchboard at 202-224-3121 and ask to be connected to your delegates’ offices. Or email your senators or representatives right now.

Also this week, a bipartisan group of House members launched the Public Lands Caucus, a congressional coalition focused on conserving and expanding access to public lands. Co-chaired by Reps. Gabe Vasquez (D-NM) and Ryan Zinke (R-MT), the caucus intends to unite lawmakers of all stripes to advance pragmatic, consensus-based public lands policy that advances conservation and supports recreation, local economies and public access.

Remember, when sportsmen unite, sportsmen win. Our system of U.S. public lands and waters is the envy of the world – and a mainstay in equal-opportunity access to all kinds of outdoor recreation, not just hunting. Let’s work together to make sure this legacy endures for future generations to experience and enjoy.

Take a stand for healthy forests. Support RGS & AWS and join our conservation network. Every donation helps us amplify your voice in important policy matters that affect wildlife, habitat and hunting.

Be part of the habitat solution! Join, renew or give a gift membership in RGS & AWS today.

What is the Proper Hold Point for Shooting Sporting Clays?

Are you looking to improve your shooting skills in sporting clays? One key factor to consider is finding the proper hold point for your shotgun. The hold point is where you pre-mount your gun before calling for the target, and it can greatly impact your shot placement. By understanding how to find your perfect hold point and implementing some tips for improvement, you can enhance your performance on the sporting clays course.

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