Weaver #12 Top Mount Base Gloss - Precision Rifle Scope Mounting Solution
- Type:
- Base - Two Piece
- Firearm Make Fit:
- Mossberg
- Finish-Color:
- Black - Gloss
- Mount Type:
- To Receiver
- Pieces:
- 1
- Model:
- Top Mount Base
- Material:
- Aluminum
- Rings Included:
- No
The Weaver #12 Top Mount Base is a precision rifle scope mounting solution engineered for shooters who need a rock-solid foundation for optics on classic and modern rimfire rifles. If you're working with H&R, Marlin, Mossberg, Remington, Savage, Sears, Stevens, or Winchester rifles, this base delivers the kind of fit and recoil management that separates a dependable setup from a frustrating one. Weaver's reputation rests on doing one thing exceptionally well: matching bases to specific gun platforms with tight tolerances and uncompromising construction.
The square-cut notch design is the backbone of this system. It mates precisely with the cross bolt in Weaver Detachable Rings, creating a mechanical lock that resists the punishment of recoil and helps keep zero intact shot after shot. You're not relying on friction or luck—you're using geometry and engineering. The gloss finish is classic Weaver, durable and straightforward. Every base ships with custom hardened fastening screws, so you have everything needed for installation without a trip back to the parts bin.
If your rifle is on the long list of supported models, this is the base that fits like it was made for it. For Remington 514 and 550 or Stevens-Springfield 85, 87, and 87/2 owners, note that drilling and tapping are required. That's honest information—not a flaw, just the reality of fitting optics to older designs. Pair this base with Weaver Detachable Rings and you've got a mounting system built on decades of field-proven design.
Key Features
- Square-cut notch design for precise engagement with Weaver Detachable Ring cross bolt
- Machined to tight tolerances for custom fit on specific rifle models
- Engineered to resist recoil movement and help maintain zero
- Includes custom hardened fastening screws
- Gloss finish
- Compatible with wide range of classic and modern rimfire rifles
Specifications
| Brand | Weaver |
| Model | #12 Top Mount Base |
| Finish | Gloss |
| Type | Precision Rifle Scope Base |
Frequently Asked Questions
What rifles does the Weaver #12 Base fit?
The Weaver #12 is designed to fit H&R 755, 765, 852, and 865; Marlin 80, 81, and 980; Mossberg 25, 26, 42, 46M, 140, 142, 43, 44, 144, 46BT, 35, 45, 46, 45A, 46B, 320, 340, 342, 620, 50, 51, 151, 152, 350, and 352; Remington 514 and 550 (drilling and tapping required); Savage 4, 5, 6, 7, and 219; Sears 42 and 43; Stevens 56, 66, 57, 76, 4171/2, and 762; Stevens-Springfield 85, 87, and 872 (drilling and tapping required); and Winchester 57, 69, 69A, 72, 47, and 74. Check the full compatibility list to confirm your exact model.
What's included with the Weaver #12 Base?
Each base comes with custom hardened fastening screws needed for installation. You'll need to pair it with Weaver Detachable Rings and your scope for a complete setup.
How does the square-cut notch design work?
The square-cut notch engages precisely with the cross bolt in Weaver Detachable Rings. This mechanical lock helps the base resist recoil movement and maintain zero stability during shooting.
Do any of these rifles require drilling and tapping?
Yes. Remington 514 and 550 rifles and Stevens-Springfield 85, 87, and 87/2 models require drilling and tapping for proper installation. All other compatible models use the base as-is.

