Magazine Base Pad Extension for FNX 45

This magazine base pad extension adds 2.5 rounds of capacity to standard FNX-45 magazines. The extra half-round capacity comes from spring compression allowance: the pad provides space for two additional rounds while leaving enough room for the magazine spring to compress fully, enabling a fully loaded magazine to seat with the slide in battery. Includes an extra-power magazine spring to maintain reliable slide lockback on the last round.

Compatibility

• FN FNX-45 (all standard capacity magazines)
• Does NOT fit FNX-40 or FNS series magazines

Key Features

• Adds 2.5 rounds capacity to standard FNX-45 magazines
• Extra-power magazine spring included – maintains slide lockback function
• Perimeter finger grooves + front-corner finger grooves for positive grip during magazine changes
• Machined notches on bottom face for color marking (magazine identification/tracking)
• Construction: machined aluminum
• Finish options: Black Type III Hardcoat Anodized, or FDE Cerakote (H-267 Magpul Flat Dark Earth – matches factory FDE frames)
• Single set screw retention – secure fit, easy disassembly
• Simple installation

Install Difficulty

2/5 – requires punch or small flathead screwdriver to drift out magazine floorplate retaining pin. No permanent modification needed.

FAQ

Will this work with my FNX-45 Tactical?

Yes. Compatible with all standard FNX-45 magazines, including those supplied with the Tactical model.

Does the included spring replace the factory magazine spring?

Yes. The extra-power spring is a direct replacement for the factory spring. It ensures the slide locks back reliably when the magazine is empty, compensating for the additional mass of two extra rounds.

Why 2.5 rounds instead of an even 3?

The 2.5-round increase accounts for the stack height needed to seat a fully loaded magazine against a closed slide. Without this compression allowance, the magazine would not lock in or the slide would not cycle. The spring compression gap prevents those issues while still providing the capacity of two additional rounds.

Shipping & Warranty

This product ships from Aftermarket Trigger Supply. Standard warranty applies against manufacturing defects. Note: Not available for sale in California, Oregon, Rhode Island, or Washington. Check local laws before ordering.