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Weaver Top Mount Extension Scope Base #40A-M Matte Beretta Mossberg 48428
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$9.99
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SKU: 48428-076683484284
Overview
This extension scope base is intended for hunters and shooters setting up compatible rifles and slug guns with a Weaver mounting system. It is machined to tight tolerances for a custom fit and uses a square-cut notch designed to mate with the cross bolt in Weaver detachable rings, helping create a secure interface for scoped setups. The fit list covers a wide range of front and rear applications, including several Remington, Weatherby, Mossberg, Beretta, and SIG Sauer models, so it is suited to owners matching a specific receiver to the correct base. Because compatibility is model-specific, it is best used when you already know your firearm’s exact action and mounting position.
Why Hunters Choose the Weaver
Machined Tight
Tolerances for a custom fit
Square-cut Notch
Weaver detachable ring cross bolts
Top-mount Extension
Design supports front and rear
Broad Fitment
List covers several popular rifle
Matte Finish
Low-profile look on the rifle
Key Features
- Weaver Top Mount Extension Scope Base #40A-M in matte finish
- Machined to tight tolerances for a custom fit
- Square-cut notch mates with Weaver detachable ring cross bolts
- Designed to help resist recoil effects
- Fits a wide range of compatible rifles and slug guns
- Compatible with front and rear mounting positions on select models
Best Used For
- Hunters mounting optics on compatible Beretta, Mossberg, Remington, or Weatherby rifles and slug guns.
- Shooters needing a Weaver top-mount base for front or rear installation on listed receivers.
- Owners of rifles with Weaver detachable rings seeking a square-cut notch and cross-bolt interface.
- Users replacing or setting up scope bases on long-action and short-action platforms from the fit list.
Specifications
| Base Type | Top Mount Extension Scope Base |
|---|---|
| Blade Finish | Matte |
| Fits | Beretta Pintail Slug Gun front and rear; BSA CF2 and Monarch Long Action 7mm, .270 and .30-06 front; Churchill Highlander front; Colt Sauer front and rear; Enfield receiver cut-down like Remington 721 front; Herters U9 round receiver front; Legacy Howa front; Mossberg 100 ATR, 1500 and 1700 front; Raptor Arms front; Remington 700, 78, 40X-L, 721 and 725 Long Action front; Remington 700, 78, 40X-S, 722 and 725 Short Action front; Remington 700 muzzleloader front; SIG Sauer 200 front and rear; Shilen round receiver front and rear; S&W 1500, 1600 and 1700 front; Weatherby Vanguard front; Weatherby Mark V Mag (not .240 mag) front |
| Model Number | 40A-M |
Pros
- Machined to tight tolerances for a custom fit on listed firearms.
- Square-cut notch is designed to mate with Weaver detachable ring cross bolts.
- Top-mount extension design supports front and rear mounting on compatible rifles.
- Broad fitment list covers several popular rifle platforms and actions.
- Matte finish offers a low-profile look on the rifle.
Considerations & Trade-offs
- This is a top-mount extension base, so fit is specific to the listed receiver and action types rather than universal across rifles.
- The fit list is broad, but it still needs to be matched carefully to the exact firearm and action length; several entries are limited to front, rear, or specific long/short action configurations.
- It is designed to work with Weaver detachable rings, so compatibility is tied to that ring system rather than every scope ring setup.
- The product description does not include installation hardware or detailed mounting instructions, so those details should be confirmed before purchase.
Suggested Comparisons
- Scope bases
- Scope rings
- Muzzleloader scope mounting systems
Suggested Accessories
- Scope rings
- Rifle scope
- Lens cleaning kit
- Torque wrench
Frequently Asked Questions
What rifles or shotguns does this Weaver Top Mount Extension Scope Base #40A-M fit?
The provided fit list includes Beretta Pintail Slug Gun front and rear; BSA CF2 and Monarch Long Action 7mm, .270 and .30-06 front; Churchill Highlander front; Colt Sauer front and rear; Enfield receiver cut-down like Remington 721 front; Herters U9 round receiver front; Legacy Howa front; Mossberg 100 ATR, 1500 and 1700 front; Raptor Arms front; Remington 700, 78, 40X-L, 721 and 725 Long Action front; Remington 700, 78, 40X-S, 722 and 725 Short Action front; Remington 700 muzzleloader front; SIG Sauer 200 front and rear; Shilen round receiver front and rear; S&W 1500, 1600 and 1700 front; Weatherby Vanguard front; and Weatherby Mark V Mag front, except .240 mag.
Is this base meant for the front, rear, or both positions?
The fit list shows both front and rear applications for some firearms, and front-only for others. Check the specific fit line for your rifle or shotgun before ordering.
What is the main design feature called out in the product description?
Weaver says each base is machined to tight tolerances for a custom fit and uses a square-cut notch that mates with the cross bolt in Weaver detachable rings.
Does the product description say what material the base is made from?
No. The provided data does not specify the material.
Will this base fit every Weatherby Mark V Magnum?
No. The fit list specifically notes Weatherby Mark V Mag front, not .240 mag.