The Oversized Scope Base Screw: What You Need To Know

The size of a scope base screw is an important consideration for rifle owners, especially those with heavier scopes. While most factory rifles are fitted with 6-48 screws, some rifle owners have expressed concerns about the durability of these smaller screws, particularly when paired with heavier scopes. To address this issue, some opt for larger screws, such as 8-40 or even 1/4-20 screws, which offer greater strength and peace of mind during rigorous hunting activities. Additionally, the use of epoxy or locktight, as well as proper torque, can further enhance the security of the scope base screws. Ultimately, the choice of screw size and additional measures depend on individual preferences and the specific scope setup.

Replacement scope base screws

When it comes to replacement scope base screws, there are a variety of options available depending on the specific firearm and scope setup you have. Here are some detailed instructions and considerations for choosing and installing replacement scope base screws:

Identifying the Correct Screw Type:

It is important to identify the correct type of screw for your scope base. The most common types are Torx head and oval head screws. Make sure to check the size and thread pattern of the screws you need. For example, common screw sizes include #6-48, #8-40, and others.

Sourcing Replacement Screws:

You can find replacement scope base screws at various retailers, both online and offline. Websites like eBay, Amazon, and specialist firearm stores are good places to start your search. When purchasing, make sure to buy high-quality screws that meet industry standards and are compatible with your firearm and scope.

Installation and Maintenance:

When installing replacement scope base screws, follow the manufacturer's instructions carefully. Ensure that you use the correct tools and techniques to avoid damaging your firearm or scope. It is also important to check and maintain your screws regularly, as they can loosen over time due to recoil and vibration.

Compatibility and Customization:

Some scope bases may require specific types or sizes of screws, so it is important to check compatibility before purchasing. If you are customizing your firearm or scope setup, you may need to source screws of different lengths or thread patterns. Always refer to the manufacturer's recommendations or seek advice from a gunsmith if you are unsure.

Common Brands and Options:

Several brands offer replacement scope base screws, including Leupold, Weaver, and Talley. These brands provide screws in various sizes and styles to fit different firearm models. It is worth checking reviews and comparing prices to find the best option for your needs.

In summary, replacing scope base screws is a straightforward process, but it requires attention to detail and a clear understanding of your firearm and scope setup. Always prioritize safety and ensure that any modifications or replacements are secure and properly installed.

Screw weight and scope size

When it comes to screw weight and scope size, it's important to understand the specifications to ensure proper mounting and stability. Let's delve into the details:

Screw Weight and Its Impact

The weight of a screw is determined by its size and material. Typically, scope base screws are made of metal alloys, with blued finishes, to ensure durability and resistance to corrosion. While the weight of an individual screw may seem insignificant, it plays a crucial role in the overall stability and balance of the scope setup. Heavier screws can add more weight to the scope base, affecting the overall weight distribution of the firearm.

Scope Size and Screw Selection

The size of the scope, particularly its objective lens diameter and tube diameter, influences the choice of screw size and weight. Larger scopes, such as those with 44mm objective lenses, may require larger and stronger screws to withstand the increased weight and recoil forces. In such cases, screws with larger diameters and thread sizes, like the 8-40 or 8-32 screws, are preferred. These screws provide a more secure hold and distribute the weight more effectively.

Screw Thread and Strength

The thread of a screw, such as the commonly used 6-48 thread, plays a crucial role in its strength. A finer thread, indicated by a higher number of threads per inch (TPI), results in a stronger screw. For example, a 6-48 screw has 48 TPI, making it stronger than a 6-32 screw with 32 TPI. This is an important consideration when matching screw weight to scope size, as heavier scopes require stronger screws to handle the additional weight.

Base Material and Screw Length

The material of the scope base and its thickness determine the appropriate screw length. For instance, the standard 1/4" length screws are often used with scope bases made of sturdy materials like exhibition-grade walnut. However, if the base has shallow holes or is made of thinner materials, shorter screws, such as those with a 3/16" length, may be more suitable. This ensures that the screw provides adequate holding power without penetrating too deeply into the base material.

Screw Weight and Recoil Considerations

The weight of the screw also comes into play when considering recoil management. Lighter screws may not provide sufficient stability, especially with heavier scopes, resulting in potential loosening or shifting of the scope during recoil. Therefore, selecting screws with appropriate weights and thread sizes for a specific scope size helps ensure that the setup remains secure and accurate, shot after shot.

Screw coating

When selecting a screw for a project, it is important to consider the type of coating it has, as this will affect the screw's performance and longevity. The most suitable coating will depend on the intended use of the screw. Here is a guide to some of the most common screw coatings:

Zinc

Zinc is one of the most common coatings for screws due to its low cost and protective properties. It helps to prevent oxidative damage, such as rusting. There are two main types of zinc coating: clear (or white) zinc and yellow zinc. Clear zinc is the most popular type of fastener coating available and is ideal for conditions with high humidity and a high risk of rusting. Yellow zinc, on the other hand, is better suited for situations where the screw may come into contact with water or other liquids, as well as humid environments.

Phosphate

Phosphate coating is another popular option for screw coatings. This process involves dipping the screws into a phosphate solution, creating a medium protective layer on the surface. Phosphate coatings are ideal for dry settings and should not be used where the screw will come into frequent contact with water.

Hot-Dip Galvanized (HD)

HD coatings are applied to steel to protect it from corrosion. They are created by coating the screw with a thick layer of zinc. This type of coating is ideal for outdoor use, especially in coastal areas with high salt content, as they take a significantly longer time to corrode compared to other coatings.

Electro-Galvanized (EG)

EG coatings use a thin layer of zinc to provide basic corrosion protection. They are typically used in areas where less corrosion protection is needed, such as kitchens, bathrooms, and roofing.

Ruspert

Ruspert coating is a new type of metal surface treatment that provides high corrosion resistance. It consists of three layers: a metallic zinc plating, a chemical conversion film, and a baked ceramic surface coating. Ruspert coating can guarantee a 500 to 1000-hour salt spray test result. It is also available in various colours, including blue, grey, silver, and red, and can be combined with other coatings for customized applications.

Dacromet

Dacromet coating is a mixture of zinc and aluminium powder, chromate, and organic dissolvent with a sticky material. It provides excellent anti-corrosion and anti-rust performance when applied to metal parts and baked at 300°C. Dacromet has been shown to provide almost 7 times the anti-rust protection of electric galvanizing.

Screw heads

Countersunk screw heads, on the other hand, are designed to sit flush with the surface of the material. Flat, oval, and bugle heads are the most common types of countersunk screw heads. Flat and oval screw heads require a countersunk hole in the material unless it is very soft. Bugle heads are commonly used for drywall screws, and their design automatically creates a countersunk hole as they are installed.

The drive style or drive recess refers to the type of tool needed to install or remove a screw. Common drive styles include slotted, Phillips, combination, hex, hex socket, square, Torx®, and spanner. Using the correct type of screwdriver or tool for the specific screw head is crucial to prevent damage to the screw or the surrounding material.

When it comes to scope base screws, they typically feature Weaver oval heads with a slotted drive style. The standard length for these screws is 1/4", but a shorter 3/16" length can be used for shallow holes.

Screw kits

When it comes to "over-size scope base screws", there are a variety of screw kits available that can help you with your scope mounting needs. Here is some information on a few of them:

Leupold Torx Screw Kit 52395

This kit includes 80 base screws and 70 ring screws. While it has received generally positive reviews, some customers have noted that it does not contain the correct screws for mounting Leupold Mark 4 bases and rings. The dimensions of the kit are 4.61 x 2.91 x 1.18 inches.

Pachmayr Master Gunsmith Torx-Style Ring and Base Screw Kit

This kit contains 10 each of 20 premium 6L-10 and 6L-15 style scope ring and base screws. It is packaged in a handy storage box with individual compartments for each size screw and also includes tweezers and a thread size gauge. The item dimensions are 7.01 x 4.8 x 0.87 inches. This kit has received mostly positive reviews, with customers praising the assortment, quality, and performance of the screws. However, there are some mixed reviews regarding the fit of the screws.

Talley Screw Kit

This kit contains 12 each of the most common screws, springs for detachable rings, and a plastic box. The screws have a TORX head, with the smaller screws using a T15 driver and the larger screws using a T25 driver. The sizes of the screws in the kit are: 6-48: 3/16", 1/4", 5/16" & 3/8".

Eagle Precision #6-48 Torx Screws for Guns

This kit contains 36 total #6-48 torx screws in oval/standard shapes.

Ultimate 6-48 Screw Kit for Red Dot Optics

While it is unclear how many screws this kit contains, it is specifically designed for mounting red dot optics.

These are just a few examples of the screw kits available for scope mounting. Each kit will have its own unique features and offerings, so it is important to review the details and customer reviews before making a purchase.

Frequently asked questions