GrovTec Mag Cap Shotgun — 1" Push-Button Magazine Cap, Black Oxide Steel — Fits Mossberg 500 12 Gauge (GTSW308 • UPC 811071013086)
Upgrade your Mossberg 500’s handling and reload ergonomics with the GrovTec 1" Push-Button Mag Cap (GTSW308) — a durable, precision-made steel accessory finished in corrosion-resistant black oxide. Designed specifically for Mossberg 500 12-gauge shotguns, this low-profile magazine cap installs in minutes and adds a reliable 1-inch of magazine tube length while preserving a clean, factory look and fast, tactile push-button operation.
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Purpose-Built for Performance and Reliability
The GrovTec Mag Cap is more than cosmetic — it delivers functional value. By extending the magazine tube by 1 inch, it gives you slightly more capacity and better control when loading and manipulating the shotgun, without requiring permanent modification or replacing the stock components. The push-button release provides positive, tool-free access for magazine disassembly or field maintenance, while the black oxide finish reduces glare and resists surface corrosion.
Precision Materials & Finish
Material: High-strength carbon steel for rugged service life and impact resistance.
Finish: Black oxide coating for corrosion resistance and low-reflective tactical appearance.
Design: Machined for tight tolerances and smooth operation with Mossberg 500 magazine cap threads and spring assemblies.
GrovTec uses quality metallurgy and machining to ensure the cap resists deformation under recoil and repeated use — giving you confidence in demanding range or field environments.
Push-Button Convenience
The signature push-button design makes it simple to remove the cap and access the magazine spring and follower for cleaning, inspection, or replacement. The button is engineered for a crisp, tactile feel so you can operate it quickly even when wearing gloves. Compared to knurled or jam-prone caps, the push-button style gives a secure positive engagement and straightforward operation.
Compatibility & Fit
Intended For: Mossberg 500 series shotguns chambered in 12 gauge.
Fit Notes: Designed to match factory magazine tube diameter and thread pattern for Mossberg 500 family shotguns. Always verify proper fit and secure engagement before live-fire use. If your shotgun has aftermarket magazine tubes, heat shields, or modified threading, consult a qualified armorer for compatibility.
Benefits & Practical Advantages
Slight Capacity Increase: 1" added magazine length can accommodate an additional shell depending on shell length and tube configuration.
Faster Maintenance: Quick push-button removal makes routine cleaning and spring/follower inspection fast and uncomplicated.
Low-Profile Aesthetic: Clean black oxide finish blends with black synthetic or metal furniture for a factory look.
Durable Construction: Steel body stands up to hard use and repeated takedown cycles.
Non-Permanent Upgrade: Installs without permanent modification to the shotgun.
Installation — Simple and Tool-Friendly
Ensure Safety First: Verify the shotgun is unloaded, the action is open, and the magazine and chamber are clear.
Remove Existing Cap: Follow manufacturer instructions to safely remove the factory magazine cap and spring assembly.
Install GrovTec Cap: Thread the GrovTec mag cap onto the magazine tube, compressing the spring/follower as required until snug. Use hand pressure; do not over-tighten.
Function Check: Cycle the action and verify secure fit, proper spring tension, and that the push-button engages and releases the cap smoothly.
Final Verification: Conduct a live-fire function check at the range to confirm reliable feeding and retention after installation.
If you’re not comfortable performing installation, have a qualified gunsmith or armorer install the cap to ensure correct spring tension and alignment.
Maintenance & Care
Wipe the cap clean with a soft cloth after use to remove powder residue and moisture.
Periodically check the push-button mechanism and spring tension for smooth operation.
Avoid harsh abrasives on the black oxide finish; use mild solvents if needed and reapply a light protective oil for long-term storage.
Replace magazine springs and followers per your routine maintenance schedule or if you detect loss of tension.
Safety & Legal Reminder
Always handle firearms safely. Keep the firearm unloaded during any maintenance or accessory installation. High-capacity magazine modifications are subject to regional laws — verify local, state, and federal regulations before altering magazine capacity or installing magazine extensions. If you are unsure about legalities in your area, consult local authorities or a qualified firearms attorney.
Technical Summary
Model: GTSW308
UPC: 811071013086
Type: 1" Push-Button Magazine Cap / Magazine Tube Extension
Material: Carbon steel
Finish: Black oxide (low-glare, corrosion-resistant)
Compatibility: Mossberg 500 series — 12 gauge (verify fit with aftermarket tubes)
Includes: Magazine cap (spring/follower typically reused from factory assembly; confirm contents with retailer)
Who Should Buy It?
Mossberg 500 owners wanting a reliable, low-profile mag-cap upgrade.
Hunters and range shooters who need quicker magazine access and streamlined maintenance.
Armorers and shop techs stocking durable spare parts for Mossberg platforms.
Shooters seeking a non-permanent capacity/ergonomic enhancement with tactical aesthetics.
Final Thoughts
The GrovTec 1" Push-Button Mag Cap (GTSW308) is a practical, well-crafted accessory for Mossberg 500 12-gauge shotguns — offering quick maintenance access, a modest capacity/handling improvement, and durable black-oxide steel construction. If you want a small but meaningful upgrade that improves day-to-day usability and keeps your shotgun looking factory-fresh, this GrovTec mag cap is a smart, affordable choice.
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