The EGW Mossberg 100 ATR and 4×4 Long Action Picatinny Scope Base (EGW part no. 45500) is a one-piece rail for the long action Mossberg 100 ATR and the Mossberg 4×4. EGW machines it from domestic 6061-T6 extruded aluminum and anodizes it matte black. It is a 0 MOA design that measures 7.458 inches long with a 4.7-inch center spread. A channel down the center trims weight, and EGW lists it as ambidextrous.

Key Specifications

• The mount is made for the Mossberg 100 ATR long action and Mossberg 4×4 long action, so it matches that receiver instead of a generic pattern.
• Built-in elevation is 0 MOA, which sets how the optic sits relative to the bore.
• It is machined from domestic 6061-T6 extruded aluminum, which keeps the mount strong without adding bulk.
• The finish is matte black anodizing, a coating that protects the aluminum from scratches and wear.
• Center spread is 4.7 inches, the distance between the two middle mounting holes.
• Overall length is 7.458 inches, which sets how much rail is available for ring placement.
• Height is 0.575 inch from the top of the receiver to the top of the Picatinny rail.
• It weighs 2 ounces, so it adds almost nothing to the rifle.
• Quick-disconnect rings are not compatible with this mount, so use standard Picatinny or Weaver rings.
• The mount is ambidextrous, with the same profile on both sides of the receiver.

Frequently Asked Questions

Does it fit the short action Mossberg Patriot or 100 ATR? No. This base is for the long action. EGW makes a separate rail for the short action Mossberg Patriot, MVP 7.62 and 100 ATR.

Can I use quick-disconnect rings? No. EGW lists quick-disconnect rings as not compatible with this base.

What does EGW recommend for installation? Measure your receiver hole spacing against the published 4.7-inch center spread, then torque the #6-48 screws to 20 inch-pounds.

Buy the EGW Mossberg 100 ATR and 4×4 Long Action Picatinny Scope Base

Order it from our EGW lineup, part of our scope accessories and parts selection, at our Lubbock, Texas gun shop for fast, direct shipping.