Best 8-40 Screws for Scope Bases: Top Picks for Secure Optics Mounting
Choosing the right screws for scope bases ensures repeatable accuracy and reliable mounting under recoil. The following selections center on common 8-40 and related threads used in rifles and precision tools. Each option covers multiple lengths, head styles, and durability features to fit a range of firearms and mounts. This guide highlights the best-suited choices for securing optics bases, rings, and rails, while noting compatibility, supply variety, and ease of installation.
Summary of chosen products
| Product | Brand | Key Benefit | Common Use |
|---|---|---|---|
| Monstrum #8-40 Gunsmithing Screw Pack | Monstrum | Mixed lengths; hardened steel; Torx T10 | Optics bases, scope rings, mounts |
| WOSUWENGE Gunsmithing Screw Set | WOSUWENGE | Blue threadlocker pre-coat; includes Torx wrench | Rifle receivers, mounts, rails |
| Eagle Precision #8-40 Screw Set | Eagle Precision | Separate head types; varied lengths | Precision tools, mounts, plates |
| Monstrum Gunsmithing Screw Set | Monstrum | Multiple lengths; Torx heads; hardened steel | Mounting bases and rings |
| KEMIFON #6-48 and #8-40 Screw Set | KEMIFON | Torx set; multiple lengths; 12mm option | Precision tools, plates, mounts |
Monstrum #8-40 Gunsmithing Screw Pack
This assortment includes six screw types in 6mm, 8mm, and 10mm lengths, available in standard and flat head variants, all crafted from hardened steel with Torx T10 heads to minimize stripping risk. A practical choice for attaching optics bases to receivers or securing scope rings and mounts, the pack helps cover a broad range of applications with a compact kit.
WOSUWENGE Gunsmithing Screw Set
This comprehensive set covers #6-48 and #8-40 threads in 6mm, 8mm, and 10mm lengths, designed for firearms maintenance and optics mounting. It includes five screws per size and pre-coated blue threadlocker to sustain tightness under recoil. A Torx wrench is included for straightforward installation, and the hardened steel construction resists wear and corrosion while reducing slip risk in demanding use.
Eagle Precision #8-40 Screw Set
Includes a mix of standard (filister) and oval head 8-40 screws in 6mm, 8mm, and 10mm lengths. This set emphasizes screw-part length distinction and compatibility with precision tools, plates, and mounts. A Torx key (T15) is included to ensure secure, torque-friendly installation against recoil and vibration.
Monstrum Gunsmithing Screw Set
This set provides six screw sizes across 6mm, 8mm, and 10mm lengths for #6-48 and #8-40 types, including five screws of each size plus a Torx Allen wrench. Hardened steel construction with Torx heads helps prevent stripping during repeated disassembly and mounting tasks, promoting long-term reliability for rifles and optics installations.
KEMIFON #6-48 and #8-40 Screw Set
Contains eight screw sizes with 6 Pcs per size and a Torx T10 wrench. The kit covers #6-48 and #8-40 screws in 6mm, 8mm, 10mm, and 12mm lengths, making it suitable for spot mounting on precision tools, plates, and mounts. The screws undergo an added hardening process for improved torque transfer and reduced stripping risk in field use.
Pachmayr Master Gunsmith Torx-Style Ring and Base Screw Kit
Torx-Style 6-lobe ring and base screws kit with 10 pieces each of two common sizes. Packaged in a storage box with compartments for easy organization, this kit focuses on versatility and quick access for scope mounts, rings, and bases on a range of firearms and precision setups.
Black Oxide Slotted Weaver Oval Head Screws
These 10-piece screws feature a black oxide finish with Weaver oval heads, designed for durable mounting of scopes and accessories. The slotted drive can be compatible with traditional installers and older equipment where Torx or hex heads are not used, balancing compatibility with corrosion resistance and steadiness under recoil.
5 Piece Of Each Size #6-48 and #8-40 Black Oxide Set
This set combines five screws of each size at 6mm, 8mm, and longer lengths, including #8-40 with T-15 Star drive and Weaver oval heads. The hardened Black Oxide Grade 12.9 construction and a Torx security bit help prevent tampering and maintain torque through multiple installations, making it suitable for rifles and mounts requiring reliable fastening.
Buying Guide: Key Considerations For 8-40 Or Related Screws
- Thread type compatibility: The 8-40 thread is common for many scope bases, rings, and mounts. Some kits also include #6-48 threads which are used in different rail and plate configurations. Match thread type to your receiver, rings, and base hardware to avoid cross-threading.
- Head style: Torx heads (T10, T15) offer better torque transfer and reduced stripping risk under recoil. Oval vs. standard (filister) heads affects flush mounting and clearance with adjoining parts. Choose head style based on your mounting surface and tool availability.
- Length selection: Lengths typically range from 6mm to 12mm or more. Shorter screws suit shallow bases or rings, while longer lengths reach deeper into mounting surfaces for a secure bite. Ensure the screw length doesn’t protrude or interfere with other components.
- Material and finish: Hardened steel provides wear resistance, while blue threadlocker pre-coating helps maintain tightness after recoil. Black oxide finishes offer corrosion resistance and reduced glare in field conditions.
- Torque and tooling: Some sets include a Torx wrench or Torx-compatible tool. Ensure you have the correct driver to apply the proper torque without stripping the screw head during installation or removal.
- Package contents: Consider whether you need mixed lengths, multiple head types, or a dedicated kit with storage and labeling. Kits with organization compartments speed up field maintenance.
- Compatibility with optics: If mounting red dot sights, scopes, or rails, verify that the included screws cover your mounting footprint ( bases, rings, Picatinny, Weaver rails).
- Quality and corrosion resistance: Hardened screws with corrosion-resistant finishes maintain performance in varied weather and field conditions.
- Installation environment: Pre-coated threadlocker can aid stability but may require additional loosening torque. Have a suitable torque wrench available if precise torque is needed for your setup.
These considerations help balance ease of use, long-term reliability, and compatibility across common rifle mounting systems. By selecting a kit that matches your base type, rail style, and preferred head design, you can improve repeatability and reduce the risk of loosening under recoil.