How to Install the triggered Disruptor FRT — Step-by-Step Guide
by Jonathan clausen on May 08, 2026
The Partisan Disruptor FRT is a true drop-in cassette trigger — no specialized gunsmithing required. If you've installed a standard AR-15 trigger group before, this install is comparable in difficulty. If you're newer to AR builds, follow each step carefully and you'll be done in under 15 minutes.
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Tools & Parts Needed
You don't need a full gunsmith setup. Here's everything required for a clean install:
An AR lower vise block isn't strictly required but makes the job significantly easier by holding your lower steady while both hands work. Well worth the $15–20 if you plan to do more builds.
Safety First
Verify your firearm is completely unloaded. Remove the magazine, lock the bolt back, visually and physically inspect the chamber. Do this every single time — no exceptions.
Separate your upper and lower receiver. You'll be working exclusively on the lower for this install. Set the upper aside in a safe location.
Remove Your Existing Trigger Group
Remove the Trigger Guard (if needed)
On most lowers the trigger guard is pinned or rolled. You may need to push out the rear trigger guard pin to give yourself clearance. Use your 3/32" punch and tap gently — don't force it. Or simplify and use your takedown tools
Drive Out the Hammer Pin
Using your 1/8" punch and hammer, drive out the hammer pin from left to right. Keep light pressure on the hammer with your thumb as the pin clears — the hammer spring is under tension and will want to move. Also using your takedown tools
The hammer pin is the rear pin of the two trigger group pins. Both pins are the same diameter but the hammer pin sits behind the trigger pin in the lower.
Drive Out the Trigger Pin
With the hammer removed, drive out the trigger pin the same direction — left to right. The trigger and disconnector will come free. Note how the disconnector spring sits inside the trigger before setting it aside — you won't need it for the Partisan install but good to understand your lower.
Remove the Selector
You do need to remove the selector/safety for the Partisan Disruptor install. Leave it in place unless you're doing a full lower overhaul at the same time. then put in the new one at the end
Install the Partisan Disruptor Cassette
The Partisan Disruptor ships as a complete pre-assembled cassette. Do not disassemble the cassette prior to installation. Install it as a single unit.
Orient the Cassette Correctly
The cassette drops into the lower trigger pocket with the trigger bow facing forward (toward the muzzle) and the hammer facing rearward. The cassette will only seat correctly in one orientation — if it doesn't drop in cleanly, check your orientation before forcing anything.
Align the Trigger Pin Hole
Drop the cassette into the lower and wiggle it until the front pin hole in the cassette aligns with the trigger pin hole in the lower. The Anti Walk pins should pass through cleanly with no resistance.
Screw in the T10 torx anti walk pins
Start the trigger walk pins. The pin should sit flush with the lower receiver wall on both sides — not proud, not recessed.
If the pin won't push through by hand, double-check that both pin holes are fully aligned. Never hammer a misaligned pin — you'll damage the cassette or the lower.
Put in the 3 position selector
Align the 3 position selector and rip it!
Verify Cassette Seating
With both pins fully seated, the cassette should have zero vertical play in the lower. Grab it and try to rock it — it should be completely solid. Any movement means a pin isn't fully seated. Check both pins before proceeding.
Function Check
Before reassembling the upper, run a manual function check on the lower:
Safety Engagement
With the selector on SAFE, press the trigger. It should not move — the safety must block trigger movement completely. If the trigger moves on safe, do not proceed. Contact us.
Trigger Reset
Move selector to FIRE. Press the trigger fully — the hammer should fall. While holding the trigger rearward, manually cycle the hammer back with your thumb. Slowly release the trigger forward — you should feel and hear a distinct reset click. This is the forced reset engaging. The trigger should reset further forward than a standard trigger group.
The reset on an FRT feels different than a standard trigger — it resets closer to the fully forward position. This is normal and by design. If there's no reset click, check that the cassette pins are fully seated.
Hammer Follow
With the selector on FIRE, hold the trigger rearward and manually cycle the hammer back. The hammer should stay cocked and not follow the bolt carrier down. If the hammer follows, the cassette may not be seated correctly — remove and reinstall.
Troubleshooting
Trigger won't reset
Check that both pins are fully seated flush. A pin that's even slightly proud can prevent the cassette from functioning correctly. Also verify your buffer and buffer spring meet the recommended spec — the Partisan Disruptor requires an H2 or heavier buffer for reliable reset. See our recommended buffer guide.
Pins won't seat flush
Lower receiver tolerances vary by manufacturer. Some lowers require very light fitting. If a pin is hitting resistance before fully seating, check for debris in the pin channel first. Do not force pins into a misaligned cassette.
Safety doesn't block trigger
This typically indicates the cassette is not fully seated in the trigger pocket. Remove both pins, reseat the cassette, and reinstall. If the issue persists contact us directly.
Hammer follows bolt carrier
Check cassette seating and pin alignment. Also check that your selector is in the FIRE position during testing — selector interference can cause false hammer follow symptoms in some lower configurations.
Visit our full Partisan Disruptor Troubleshooting Guide or reach out directly through our The Triggered Company contact page. We'll get you sorted.
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