Apex Extra Power Magazine Spring Set

If you’ve noticed your SA-35 or FNX-45 not locking back on the last round, or the cartridge lift feels sluggish during the feeding cycle, this extra power magazine spring set is a simple fix. It replaces the factory spring with a stiffer coil that provides more consistent upward pressure on the follower. That means a more positive slide lock when the mag runs dry, and smoother, more reliable feeding as the stack empties. We’ve found this especially helpful on pistols that see a lot of range time or are used with aftermarket magazine extensions.

Compatibility

• FNX-45 magazines only when used with an Apex magazine extension installed
• Apex 19-round magazines for the Springfield SA-35 series pistols
• Not recommended for the Apex 17-round magazine for the SA-35
• Not recommended for factory SA-35 magazines without this kit

Key Features

• Made from Rocket Wire – a high-strength spring steel that holds its tension over thousands of cycles
• Manufactured in the USA to Apex’s own specifications by a dedicated spring shop
• Improves slide lock-back consistency on the last round
• Helps keep the follower and cartridge stack feeding smoothly as the magazine empties

Install Difficulty: 2 out of 5

You’ll need a punch or small flathead screwdriver to depress the magazine catch button inside the basepad, and a pair of pliers to compress the spring while you reassemble the follower and baseplate. It’s a straightforward swap – just take your time with the spring tension. We’ve got a video on our install page showing the whole process.

Frequently Asked Questions

Will these springs work in my factory SA-35 magazine?

No. These are designed specifically for the Apex 19-round SA-35 magazines. Factory SA-35 mags use a different follower and baseplate geometry, so the spring won’t fit correctly.

Can I use these in an FNX-45 without the magazine extension?

We don’t recommend it. The extra power spring is meant to compensate for the added length and weight of the extension. Without it, the spring may stack too tightly inside a standard-length magazine body and cause feeding issues.

How many springs come in the set?

This is a set of two springs – enough to rebuild two magazines.

Shipping & Warranty: We ship same-business-day on orders placed before 2 PM Eastern. These springs are covered by Apex’s limited lifetime warranty against material or workmanship defects. If you have a problem, just give us a call – we’re a family shop and we stand behind what we sell.