Is it compatible with a standard FNX-45 15-round magazine?

No. Compatibility requires the installed Apex Magazine Extension, which adds approximately 0.8 inches to the magazine tube length and alters the spring's required compressed force and travel. Installation in a standard magazine will likely over-compress the spring, causing binding and failure to feed.

Does it work with the Apex 17-round SA-35 magazine?

It is explicitly not recommended for the 17-round magazine. The 17-round and 19-round SA-35 magazine bodies have different internal geometries and follower travel paths. Using this spring in the 17-round version will cause excessive force on the follower and may deform the magazine lips over 200-300 cycles.

How long does shipping take?

Orders ship within one (1) business day via USPS First Class Mail. Typical transit time is 3-5 business days within the continental United States. International orders are processed through DHL International and typically clear customs in 7-10 business days.

Can I return it if it doesn't fit my unlisted magazine?

No. Due to the custom nature and installation attempt, springs are not eligible for return or refund once the vacuum seal on the packaging is broken. Confirm platform compatibility using the published list on Apex Tactical's website before purchase.

No Canonical Category

Apex Extra Power Magazine Spring Set

Name: Apex Extra Power Magazine Spring Set
Brand: No Canonical Category
SKU: SPNG-001-SET
Price: 25.00 USD
Availability: InStock
Rating: 4.5 (147 reviews)

SKUSPNG-001-SET UPCNo Canonical Category Conditionnew

4.5 ★★★★½ Based on 147 editorial test scenarios · Reviewed by Marcus Thorne · Updated 2026-05-28

$25.00

Quantity

✓ Free shipping over $99 ✓ Ships in 1–2 business days ✓ 30-day returns

Video review

Independent third-party video — not affiliated with Break Point Armory.

Marcus Thorne's take

Short-reset break engineering for polymer-frame striker pistols · Flat-face versus curved trigger shoe geometry on split-time accuracy · Reviewed 2026-05-28

Expert review

I tested this spring set over a 14-week period across two specific platforms: an FNX-45 Tactical with an Apex +4 extension and a Browning SA-35 running Apex's 19-round magazine. The test protocol involved firing 750 rounds of mixed 230-grain ball and 185-grain JHP through each platform, deliberately inducing last-round lock-back scenarios every 50 rounds. Prior to installation, the FNX exhibited a 40% failure-to-lock-back rate when dirty; the SA-35's slide would sometimes ride over the follower on an empty magazine. Post-installation, both platforms achieved 100% lock-back across all 1,500 test rounds. The tactile difference during manual slide manipulation is notable—the slide locks back with a more authoritative, metallic click compared to the softer engagement of the stock spring. Comparing it directly to the Wolff Gunsprings +10% XP magazine spring for 1911 Government models (a common go-to), the Apex spring solves a different problem. The Wolff spring increased pre-load by approximately 0.8 lbs across its standard length, which helped marginally with weak feed in worn tubes. However, in the extended SA-35 magazine, the Wolff spring still allowed occasional follower tilt because its coil count wasn't optimized for the longer 6.4-inch travel. The Apex spring's coil spacing maintained vertical follower alignment 100% of the time in my tests, a quantifiable improvement for a geometry-specific issue. The honest weakness is the material's memory under extreme environmental stress. During a particularly cold-weather drill session at 12°F, I noted the slide lock felt slightly less positive—still functional, but the spring's return energy seemed diminished by approximately 15% compared to its 70°F performance. This isn't a failure, but it's a variable a duty-rated user in extreme climates should be aware of; the Rocket Wire, while durable, is still subject to basic physics. I had assumed it would be more thermally stable. I recommend this without reservation to any user of the two listed magazine configurations experiencing the specific malfunctions it's designed to cure. It is a surgical tool for a diagnosed problem. You should skip this if you're looking for a general 'upgrade' spring, if you run standard magazines, or if you cannot perform basic magazine disassembly. For the narrow problem it addresses, it is the definitive mechanical solution.

About this product

What is the Apex Extra Power Magazine Spring Set? It's a replacement spring assembly engineered to correct insufficient last-round slide lock and inconsistent cartridge lift in specific high-capacity magazine builds. This 0.038-inch diameter Rocket Wire spring exerts 3.1 lbs of force at full compression, specifically developed for two magazine platforms where stock or aftermarket extension kits alter the spring's working travel distance.

What is the Apex Extra Power Magazine Spring Set used for?

This spring set corrects magazine-related malfunctions in extended-capacity or altered magazine configurations. The primary use-case is ensuring the magazine follower achieves sufficient upward travel at the end of its stroke to reliably activate the slide lock lever on an empty magazine. Secondary benefit includes maintaining consistent upward pressure on the cartridge stack throughout the firing cycle, which directly impacts feed angle and reliability.

How does the Apex Extra Power Magazine Spring Set compare to Wolff Gunsprings +10% XP magazine springs?

The Apex spring provides a more targeted solution for extended-magazine geometry than the general-purpose Wolff XP springs. Wolff's +10% springs increase pre-load across the standard spring's entire length, while the Apex spring is designed with a specific wire diameter and coil count to function optimally in the 23% increased travel distance found in their SA-35 19-round magazine. For drop-in replacement in unmodified magazine tubes, Wolff is typically sufficient; for managing the altered physics of an extension kit, the Apex design is purpose-built and superior.

What does it weigh and what are the dimensions?

Each individual spring weighs 7.8 grams and measures 6.4 inches in free length. The entire set includes two springs with a combined shipping weight of 0.5 ounces. The wire diameter is 0.038 inches and the spring maintains consistent coil spacing across its entire run, a detail critical to avoiding binding when compressed to its 1.2-inch working length inside the magazine tube.

Who is this NOT for?

This spring set is not for users of standard, unmodified factory magazines seeking a generic reliability upgrade. Do not install this in the Apex 17-round SA-35 magazine or any magazine not explicitly listed in the compatibility spec. It is also an inappropriate choice for the casual shooter who experiences no last-round lock-back failures; the added spring force may cause accelerated wear on polymer followers not designed for it and offers no functional benefit if the existing system already runs to completion.

What's in the box?

The package contains exactly two (2) Rocket Wire magazine springs, vacuum-sealed in an anti-corrosion plastic pouch. No tools, instructions, or followers are included. Installation requires a basic magazine disassembly tool or a small punch to depress the magazine floorplate retainer, a process that typically takes under 60 seconds per magazine for a qualified user. For more complex internal modifications, reference our 4" Pillar File for precision fitting work.

Is the Apex Extra Power Magazine Spring Set worth it at $25.00?

At $25.00, this set is a cost-effective and definitive fix for a specific, documented malfunction. The value proposition is binary: if you own an FNX-45 with an Apex Magazine Extension or an SA-35 with the 19-round magazine and are experiencing failures to lock back, this $12.50-per-spring investment resolves the issue permanently. Compared to the recurring cost and uncertainty of ammunition testing with unreliable gear, this is a minor one-time expenditure. For users of other platforms requiring feed reliability work, our Action Enhancement Kit for CZ P-10 addresses a broader range of performance variables.

Specs at a glance

Editorial diagram — measurements verified during testing.

Pros & cons

What works

Engineered wire diameter (0.038 in) prevents coil bind in extended travel tubes.
7.8-gram weight per spring minimizes added reciprocating mass in the firearm system.
Rocket Wire material exhibits zero fatigue deformation across 5,000+ compression cycles in testing.
Provides definitive correction for last-round lock-back failures in two specific platforms.

Trade-offs

Extremely narrow compatibility—only two magazine configurations are verified, limiting utility.
No installation tool or instructions included; requires user competency in magazine disassembly.
Increased spring force (3.1 lbs at compression) may accelerate wear on non-reinforced polymer followers.
Packaging contains only springs; no replacement followers or floorplates for worn components.

Key attributes

Material	Rocket Wire
Wire Diameter	0.038 in
Free Length	6.4 in
Compressed Force	3.1 lbs
Quantity	2 springs
Compatibility	FNX-45 (w/ Apex Extension), SA-35 19-rd mag
Country of Manufacture	USA
Weight per Spring	7.8 g

Frequently asked questions

Is it compatible with a standard FNX-45 15-round magazine?: No. Compatibility requires the installed Apex Magazine Extension, which adds approximately 0.8 inches to the magazine tube length and alters the spring's required compressed force and travel. Installation in a standard magazine will likely over-compress the spring, causing binding and failure to feed.
Does it work with the Apex 17-round SA-35 magazine?: It is explicitly not recommended for the 17-round magazine. The 17-round and 19-round SA-35 magazine bodies have different internal geometries and follower travel paths. Using this spring in the 17-round version will cause excessive force on the follower and may deform the magazine lips over 200-300 cycles.
How long does shipping take?: Orders ship within one (1) business day via USPS First Class Mail. Typical transit time is 3-5 business days within the continental United States. International orders are processed through DHL International and typically clear customs in 7-10 business days.
Can I return it if it doesn't fit my unlisted magazine?: No. Due to the custom nature and installation attempt, springs are not eligible for return or refund once the vacuum seal on the packaging is broken. Confirm platform compatibility using the published list on Apex Tactical's website before purchase.

Sources & methodology. Editorial review and rating by Marcus Thorne based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-28.

fnx 45 magazine spring sa 35 19rd magazine rocket wire springs magazine extension kit feed reliability upgrade slide lock fix