Weaver #S45 Grand Slam Top Mount Base - Matte Finish

The Weaver #S45 Grand Slam Top Mount Base is a steel rifle scope mounting base engineered for shooters who need reliable, rock-solid support on a wide range of modern and classic rifle actions. Built from high-strength steel and finished in matte to reduce glare, this rear-position base pairs with compatible front bases to deliver the secure two-point foundation your scope demands—whether you're setting up a hunting rifle, a precision target gun, or a tactical build. The S45 fits numerous rifle actions across multiple manufacturers, making it a versatile choice for gunsmiths, builders, and hunters working with vintage Mausers, H&R rifles, Herter's FN actions, CIL models, Colts, Muggraves, Parker Hales, Voeres, and other popular platforms.

This is a single base—you'll need to order both front and rear bases to complete your setup. Weaver's Grand Slam design accommodates standard Weaver scope rings and integrates with both standard and extended receiver cuts, giving you mounting flexibility for different scope heights and eye relief needs. The matte steel finish resists corrosion and blends with most rifle stocks and metal work, keeping the focus on function rather than flash.

Whether you're restoring a classic rifle or building a custom hunter, the Weaver #S45 delivers the straightforward, dependable performance that has made Weaver a trusted name in scope mounts for generations. Pair it with the matching front base designated for your rifle's action, and you've got the foundation for years of reliable shooting.

Key Features

• High-strength steel construction for secure scope mounting
• Matte finish minimizes glare and reflection
• Fits numerous rifle actions and receiver types (see compatibility list)
• Works with standard Weaver scope rings
• Rear-position base—order front base separately
• Compatible with both standard and extended receiver configurations

Specifications

Product	Weaver #S45 Grand Slam Top Mount Base
Brand	Weaver
Position	Rear
Finish	Matte
Material	Steel
Mount Type	Top Mount

Frequently Asked Questions

What rifles does the Weaver S45 base fit?

The S45 is a rear base that fits a broad range of rifle actions, including CIL 972-C, Colt 57, H&R 300/301 (pre-1973), Herter's J-9 FN action, Knight LK-93/Wolverine/Legend, Mauser 455 and model 98 with extended receiver, Musgrave Mark III and IV, Parker Hale 1000/1000C/1100/1200/1700, Sears 50/51 FN action, Springfield 03-A3 (front only), Voere 2150/2165 Mauser action, and others. Consult the detailed compatibility list or verify with your rifle's specifications before ordering.

Do I need to order a front base separately?

Yes. The S45 is a rear base only. You must order a matching front base for your specific rifle action to complete the two-point mounting system. The correct front base depends on your rifle model—common front bases paired with S45 rears include S46, S402, and S466, depending on your action type.

What scope rings work with the Weaver S45 base?

The S45 is designed to accept standard Weaver scope rings. Ensure your rings are compatible with Weaver-pattern bases and that they are appropriately sized for your scope's objective bell diameter.

Is the matte finish corrosion-resistant?

The matte steel finish is designed to resist glare and corrosion. For long-term protection in wet or harsh conditions, periodic maintenance and proper storage are recommended, as with all steel components.