ALG Defense Quality Mil Spec Trigger QMS Drop In 6 5 Pound Pull 05 198 UPC 854014005205
Product Description
The ALG Defense® Quality Mil-Spec (QMS) Trigger (SKU: 05-198 / UPC: 854014005205) is engineered by Amy Lynn Geissele to elevate the baseline AR-15 fire control group without compromising defensive reliability. Designed specifically for duty, defensive staging, and competition divisions requiring a strict standard trigger pull weight, the QMS removes the notorious roughness, grittiness, and inconsistent stacking inherent to mass-produced lower parts kits while maintaining a 100% combat-reliable single-stage 6.5-pound break.
Manufactured under the rigorous oversight of Geissele Automatics engineering, each QMS hammer and trigger is cast from mil-spec 8620 alloy steel and hardened to strict Rockwell standards. Sear geometry surfaces are expertly honed and surface-polished before receiving a MIL-DTL-16232 manganese phosphate conversion coating. This military-standard phosphating creates an oil-retaining, corrosion-resistant exterior that withstands extreme field environments, hard running, and harsh solvent exposure without flaking or dimensional breakdown.
Unlike cassette-style modules that struggle with fine particulate intrusion, the QMS preserves open-architecture mil-spec geometry, making it impervious to sand, carbon, and mud buildup. Equipped with a full-power hammer spring, the assembly provides uncompromising primer ignition energy across hard-primered NATO 5.56x45mm, commercial .223 Remington, and steel-cased surplus ammunition, delivering duty-grade trigger control at an exceptional price point.
*Armorer Bench Notes & Real-World Staging Guidance:*
Fitment Matrix: Direct fit for all AR-15, AR-10, LR-308, and pistol-caliber carbine lower receivers equipped with standard 0.154" trigger/hammer pin holes. CRITICAL: Will NOT fit legacy Colt large-pin (0.170") lower receivers without offset adapter bushings. Although distributors frequently classify this unit as a "drop-in" trigger, it is a traditional multi-piece fire control group requiring standard hammer, trigger, disconnector, and spring installation into the receiver pocket.
- Ensure the host firearm is completely clear, magazine removed, and chamber visually and physically verified empty.
- Drive out existing 0.154" hammer and trigger pins from the receiver using a non-marring bench block and armorer's punch, removing the old fire control group.
- Assemble the disconnector spring (wide base down) into the trigger base, align the disconnector, seat the trigger assembly into the lower receiver, and insert the slave pin to capture the 0.154" trigger pin from left to right.
- Orient the heavy-duty hammer spring legs over the trigger pivot pin, cock the hammer downward into alignment, and drive the 0.154" hammer pin fully through until detent j-springs mechanically click into place.
- Perform a full mechanical function check: cycle the action on SAFE (hammer must not fall), switch to SEMI and dry-fire into a receiver-protected block, hold the trigger rearward while cycling the charging handle to verify positive disconnector reset, and release to confirm crisp reset engagement.
Key Features
- Geissele Engineering Pedigree: Developed and tuned under strict quality parameters to deliver a clean, consistent break exceeding mil-spec expectations.
- Honed Sear Geometries: Precision-polished engagement surfaces eliminate the gritty creep and stacking typical of factory mil-spec fire control groups.
- Duty-Grade Pull Weight: Delivers a safe, predictable single-stage pull calibrated between 5.5 and 6.5 lbs, fully meeting regulatory and institutional requirements.
- Full-Power Primer Strike: Factory-weighted hammer spring guarantees reliable primer detonation across mil-spec NATO 5.56, .308 Win, and hard-primed military surplus ammunition.
- MIL-DTL-16232 Manganese Phosphate: Heavy-duty combat finish delivers exceptional lubricant retention, abrasion resistance, and chemical protection.
- Standard 0.154" Pin Architecture: Retains standard AR platform open architecture for unmatched debris clearance and universal small-pin receiver fitment.
Product Specifications
- Brand: ALG Defense®
- Model/Series: Quality Mil-Spec (QMS) Trigger
- MPN / SKU: 05-198 / 05198
- UPC: 854014005205
- Trigger Type: Single-Stage Combat Trigger
- Trigger Profile: Traditional Mil-Spec Curved Bow
- Pull Weight: ~6.5 lbs (Meets 5.5 lb Mil-Spec Minimum)
- Pin Size: Standard Small Pin (0.154")
- Material: 8620 Alloy Steel
- Finish: MIL-DTL-16232 Manganese Phosphate
- Platform Compatibility: AR-15 / M4 / M16 / AR-10 / SR-25 / LR-308 (0.154" Pin Receivers)
- Country of Origin: United States
