Best 8-40 Scope Base Screws for Optics Mounts and Rails
The top choice for securing optics mounts, scope rings, and rails uses #8-40 screws. This guide highlights five reliable options, explains who each is best for, and helps you compare head styles, lengths, and coatings. Whether you’re assembling a precision rifle setup or upgrading a scope mount, these screws are designed to resist stripping and recoil. The selections below cover standard, oval, and Torx variants to fit most receivers, bases, and rings. A quick buyer’s table follows to help you compare at a glance.
| Product | Thread | Head Style | Lengths | Best For |
|---|---|---|---|---|
| Monstrum #8-40 Gunsmithing Screw Pack | #8-40 | Standard & Flat (Torx T10) | 6mm, 8mm, 10mm | Versatile kits for optics bases and scope rings |
| 37 Pcs #8-40 Gunsmithing Screws (Standard & Oval) | #8-40 | Standard & Oval | 6mm, 8mm, 10mm | Wide applicability with included installation wrench |
| WOSUWENGE Gunsmithing Screw Set | #6-48 & #8-40 | Torx | 6mm, 8mm, 10mm | Comprehensive set with blue threadlocker |
| Eagle Precision #8-40 Screw Set | #8-40 | Standard & Oval | 6mm, 8mm, 10mm | Precision projects with both head styles |
| Gunsmithing Screw Set for Optics Mounting | #6-48 & #8-40 | Blue-threadlocked Torx | 6mm, 8mm, 10mm | Pre-coated reliability for optics mounting |
Monstrum #8-40 Gunsmithing Screw Pack | 6mm, 8mm, and 10mm
Best for versatile builds where you need both standard and flat head options in multiple lengths. Monstrum’s pack includes 6 screws of each size in 6mm, 8mm, and 10mm lengths, plus Torx T10 heads to minimize stripping. This makes it a solid all-around choice for attaching optics bases to receivers or securing scope rings and mounts. Choose this if you want a ready-to-go kit with common head styles and reliable steel construction. A potential limitation is the mix of standard and flat heads; ensure your mounts accept both without interference.
37 Pcs #8-40 Gunsmithing Screws (Standard & Oval Head)
Best for a comprehensive, long-term spare set with both standard and oval heads. Each length (6mm, 8mm, 10mm) has six screws, and the package includes an installation wrench for convenient setup. This kit is ideal for shooters who frequently swap optics or rails and prefer a robust Grade 12.9 hardened alloy with black oxide finish for corrosion resistance. Limitation: confirm exact thread fit before purchase to avoid incompatibility with your receiver or rail type.
WOSUWENGE Gunsmithing Screw Set (6-10mm) for Optics Mounting
Best for a comprehensive pre-assembled kit with blue threadlocker and a Torx wrench. Includes both #6-48 and #8-40 screws in 6mm, 8mm, and 10mm lengths, five screws per size, designed for rifles, scope rings, Picatinny, and Weaver rails. This setup is suitable for those who want reliable pre-treated hardware that resists loosening under recoil. Caution: verify your system uses #6-48 or #8-40 threads since mixes can cause mounting issues if mismatched.
Eagle Precision #8-40 Screw Set | 36 Pcs
Best for projects requiring both standard and oval heads in 6mm, 8mm, and 10mm lengths. The set provides distinct counts for the standard-head and oval-head screws and includes a Torx Key (T15). It’s a solid pick for precision mounting where head style choice matters for fit and clearance. Limitation: the listing separates measurements by head type, which may require careful counting to ensure you have enough of each variant for your build.
Gunsmithing Screw Set for Optics Mounting (6-48 & 8-40)
Best for pre-coated reliability with blue threadlocker. This kit includes both #6-48 and #8-40 screws in 6mm, 8mm, and 10mm lengths, five screws per size, and a Torx wrench for straightforward installation. It’s well-suited for optics mounting on rifles where vibration and recoil could loosen fasteners. Caution: verify thread compatibility with your specific bases and receivers before buying to avoid mismatches.
Eagle Precision Combo Optics Mount Screw Kit
Best for a high-strength option when using both 6-48 and 8-40 threads across 6mm, 8mm, and 10mm. The kit includes multiple combinations of oval and fillister heads, providing flexibility for different optics mounts and receivers. It’s a strong choice when you need reliable performance in a military-grade context, with clear head-style options for clearance and torque considerations. Limitation: ensure your setup requires both thread types to justify carrying both in one kit.
Black Oxide Star Drive Weaver Oval Head Screws
Best for rugged builds where a Weaver oval head and star drive torque are preferred. These 10-count screws use a black oxide finish for corrosion resistance and have a full-thread length suitable for base and rail applications. Choose this if you value a simpler, consistent head drive under field conditions. Limitation: they are limited to a 1/4″ length, which may not fit all setups requiring longer screws.
Buying Guide: Key Considerations For 8-40 Scope Base Screws
- Thread compatibility: Confirm the target parts use #8-40 threads (common in optics mounts and many rails). Some kits include additional thread types like #6-48; avoid mismatches.
- Head style: Standard, oval, flat, or Torx heads affect fit with ring caps and bases. Torx heads reduce stripping risk under high torque.
- Length selection: 6mm, 8mm, and 10mm lengths cover most mounting scenarios. Longer screws can reach through certain mounts, shorter screws avoid protrusion.
- Coating and material: Hardened steel with black oxide or blue threadlocker provides corrosion resistance and improved vibration resistance. Threadlocker helps maintain tightness under recoil.
- Torque and tool compatibility: Torx drivers are common for 8-40 screws; verify your tool set includes the correct bit size to minimize cam-out and stripping.
- Quantity and redundancy: Kits with multiple screws per size are ideal for frequent field maintenance and replacements.
FAQ
- Q: Are #8-40 screws universal for optics mounts? A: They are widely used for scope bases and rings, but always verify thread compatibility with your specific rail or receiver.
- Q: Should I use threadlocker on scope mounting screws? A: Blue threadlocker is common in kits to reduce loosening from recoil, but follow mounting instructions for your barrels and optics.
- Q: Which head style is best for flat-top receivers? A: Standard heads are versatile; oval heads can offer better clearance with certain ring designs.
- Q: What length should I choose? A: 6mm, 8mm, and 10mm cover typical mounting depths. Use the shortest length that fully engages the base or rail.
- Q: Do these kits include a Torx wrench? A: Some sets include a Torx wrench; others require a separate driver with a Torx bit. Check product details before purchasing.
- Q: How many screws do I need for a complete mount? A: A typical optics mount requires multiple screws for each rail and ring; buying a kit with several screws of each size provides flexibility and redundancy.