Firearm Stop Springs
Slide Stop & Bolt Catch Springs — Precision Engineered for Reliable Operation
High-performance stop springs are some of the smallest components in a firearm, yet they dictate the functionality and tactile feel of critical user controls. At Anderson Quality Spring, we design and manufacture precision slide stop springs, bolt catch springs, and cylinder stop springs in-house. Whether it is a tiny torsion spring with precise leg angles or a micro-compression spring, our custom spring manufacturing capabilities allow us to deliver these intricate components with absolute consistency. Trusted by OEMs, custom gunsmiths, and aftermarket parts manufacturers, our stop springs ensure your firearm locks back when it should—and releases exactly when commanded.
Introduction to Firearm Components
Firearm springs are the foundation of any gun’s reliability and performance. While recoil and mainsprings handle the heavy lifting of cycling and ignition, the smaller “stop” springs govern the manual and automatic controls of the weapon. These include the springs that power the slide stop (or slide release) on semi-automatic pistols, the bolt catch on AR-style rifles, and the cylinder stop in revolvers. Because these springs constantly interact with the shooter’s inputs and the magazine follower, they require exact tension. Correctly specified stop springs prevent premature slide lock, ensure reliable last-round hold-open, and provide the crisp, tactile feedback expected from a high-quality firearm.
Why Stop Springs Matter
- Ensure reliable last-round lock-back: Provide the precise resistance needed to allow the magazine follower to push the stop upward when empty.
- Prevent premature engagement: Maintain enough downward tension to keep the slide stop or bolt catch from engaging under heavy recoil before the magazine is empty.
- Provide tactile operator feedback: Deliver a crisp, positive click when manually engaging or disengaging the weapon’s controls.
Well-specified stop springs keep the firearm’s user interface running flawlessly, ensuring predictable manual of arms and preventing frustrating feeding or locking malfunctions.
Stop Spring Information
Slide Stop / Slide Release Springs (Pistols)
Designed to maintain downward pressure on the slide stop lever. Often manufactured as complex wire forms or miniature torsion springs:
- Standard tension springs for factory replacement and duty use
- Custom wire forms tailored to proprietary frame and locking block geometries
Bolt Catch / Bolt Release Springs (Rifles)
- Standard bolt catch springs for mil-spec AR-15 and AR-10 lower receivers
- Enhanced springs for ambidextrous lowers or custom billet receivers requiring different spring rates
Cylinder Stop Springs (Revolvers)
- Highly engineered to prevent cylinder “throw-by” during rapid double-action firing.
Materials & Finishes
Our manufacturing services include a variety of standard and specialty materials to meet precise specifications for these intricate springs:
- Music wire — High-strength and economical, commonly used for internal stop springs where heavy corrosion isn’t a primary concern.
- Stainless steel — Excellent corrosion resistance, ideal for maritime environments, everyday carry (EDC) pistols, and components exposed to sweat and the elements.
Finishes & Coatings: We offer advanced finishing techniques including passivation for stainless parts, zinc plating, or standard phosphate coatings to ensure smooth interaction with the firearm’s frame and levers.
Manufacturing & Quality Control
- Precision CNC Wire Forming: Slide stop springs often require complex, multi-axis bends. Our advanced CNC wire-forming equipment ensures perfect leg angles and loop diameters on every single part.
- Dimensional Accuracy: Because stop springs often fit into tiny, machined recesses within the firearm frame, we maintain incredibly tight tolerances on wire diameter and outside dimensions to prevent binding.
- Batch traceability and rigorous in-process inspections are standard for our high-volume OEM manufacturing.
Compatibility & Customization
We manufacture springs designed for drop-in compatibility across major platforms, including 1911s, modern polymer striker-fired pistols, and AR-platform lower receivers. Our custom spring manufacturing capabilities include rapid prototyping and engineering assistance. If you are developing a new ambidextrous bolt catch or a proprietary pistol frame, our engineers will work from your CAD model, blueprint, or functional requirements to produce exact prototypes and seamless full production runs.
Testing & Reliability
Every production lot includes:
- Strict dimensional inspections (using optical comparators for complex wire forms) to ensure perfect seating within the frame.
- Load testing for torque (torsion springs) and kinetic energy resistance.
- Visual and dimensional final inspections.
- Full traceability.
Regular inspection of stop springs is recommended, especially for competition shooters who frequently manipulate slide and bolt releases.
Applications
- OEM production for major firearms manufacturers (pistols, rifles, shotguns, revolvers)
- Aftermarket upgrades for competition and ambidextrous control kits
- Military and law enforcement replacement parts
- Custom wire forms for proprietary locking mechanisms
Installation & System Integration
Effective performance of a slide or bolt stop system depends on the precise integration of the spring within the frame’s architecture. Small deviations in wire form angles can cause the slide stop to drag against the slide, or fail to engage the magazine follower properly. During prototype development, dimensional verification within the physical firearm frame is essential.
Our engineering support team collaborates with OEM and aftermarket partners to evaluate tolerance stack-ups, validate spring behavior, and ensure your controls feel crisp, positive, and reliable.
Ordering, Prototyping & Lead Times
We support single-sample prototyping and high-volume full production. Please provide a sample, drawing, or specification sheet, and our sales professionals and engineering team will quote materials, processes, pricing, and lead time. For OEM projects, we offer seamless JIT and Kanban support.
All of our products are manufactured in the USA to ensure the highest quality, safety, and reliability.
Safety, Compliance & Warranty
- Certified Quality: Anderson Quality Spring’s Quality Management System is certified to ISO 9001:2015 and IATF 16949:2016 standards.
- Products shipped for lawful use only.
- Limited warranty against manufacturing defects — see warranty page for details.
Let’s Dial in Your Design
Ready to specify a slide stop, bolt catch, or custom wire form?
Request a quote, submit a sample, or talk to an applications engineer today.
BRING US YOUR DESIGN
AQS offers full-service manufacturing of springs and wire forms. We can work together with you and your team to manufacture the custom components you require for your unique applications. Submit your drawings and get started today!