Geissele Super Dynamic 3-Gun SD-3G Trigger - AR-15 Flat Bow
Mix and match across the range: 2 items save 5%, 3 save 10%, 4 or more save 15% on your whole basket.
Drop-in fit for AR-15/M4 pattern lower receivers with mil-spec trigger pins. Confirm pin size before ordering.
Not sure it fits your rifle? Ask us before you order
The Geissele Super Dynamic 3-Gun (SD-3G) is a flat-bow competition trigger for AR-15 and M4 pattern rifles, fitting Mil-Spec lower receivers that use .154 in trigger and hammer pins.
Competition speed behind a flat bow — the SD-3G is Geissele's race trigger for shooters who count in tenths.
The Geissele Super Dynamic 3-Gun (SD-3G, 05-166) pairs the S3G's hybrid internals with the flat Super Dynamic trigger bow. The result is a short, light, rolling break with a very fast reset — engineered for the split-times of 3-Gun and action shooting — delivered through a shoe that keeps your finger placement identical on every stage, every target, every transition.
Geissele builds its competition triggers with the same metallurgy and quality control as the rest of its line, so running fast does not mean running fragile. If your scores hinge on speed and precision inside the same stage, this is the trigger built for the job.
Drop-in fit for AR-15/M4 pattern lower receivers with Mil-Spec .154 in trigger and hammer pins, which includes UK straight-pull AR-15 lowers. On a straight pull the flat bow and short, light break are what you feel; the very fast reset matters less than it does on a self-loader, so consider Geissele's two-stage models too. Large-pin receivers are not compatible — confirm your pin size first. Install at the bench, verify function and safety, then go find a shot timer.
| Platform | AR-15 / M4 |
|---|---|
| Fits | Mil-Spec lower receivers with .154 in trigger and hammer pins |
| Type | Competition trigger, flat bow |
| Made in | USA |
| Brand | Geissele Automatics |
| MPN | 05-166 |
Built for the clock. Order the SD-3G today — imported from the USA with all duties paid by us and dispatched tracked from the UK in 7–10 business days, with nothing to pay on delivery.
Explore more: all Rifle Triggers, AR-15 Parts & Accessories or browse all Geissele Automatics.
| Platform | AR-15 / M4 |
|---|---|
| Fits | Mil-Spec lower receivers with .154 in trigger and hammer pins |
| Type | Competition trigger, flat bow |
| Made in | USA |
| Brand | Geissele Automatics |
| MPN | 05-166 |
| Category | Trigger |
| Shipping weight | 0.2 kg |
| Barcode | 854014005076 |
£5 tracked UK delivery on every order via Royal Mail Tracked 24. Our products are ordered in from the manufacturer rather than held in UK stock, so please allow 7 to 10 business days (Monday to Friday, excluding bank holidays) from the date of your order for it to reach you. Tracking details are emailed on dispatch. UK delivery only.
You have 30 days from receiving your order to cancel it for any reason, then 14 days to send it back unused and in its original packaging. Faulty, damaged or incorrect items are replaced or refunded and we cover reasonable return postage. Refunds go back to your original payment method within 14 days of receiving the return.
It drops into AR-15/M4 pattern lower receivers that use mil-spec trigger pins. Confirm your pin size before ordering, as large-pin lowers need a different trigger. If your receiver is an unusual make, send us the details and we'll check compatibility.
As the name suggests it is built for 3-gun and similar competition: a competition trigger on a flat bow, intended for fast, repeated shots where a short, positive break matters more than a long deliberate press. The flat shoe gives a consistent finger position at speed. It is not the choice for a general-purpose duty carbine.
The <a href="/products/geissele-s3g-super-3-gun-trigger">S3G</a> is a single-stage hybrid with a very short, fast reset, while the SD-3G brings the Super Dynamic flat bow to the competition format. Which you prefer usually comes down to whether you like taking up a stage before the break or want everything to happen in one motion. Both are aimed at the same kind of shooting.
Nothing beyond your existing trigger and hammer pins, assuming they are serviceable. It is supplied in one configuration, so there is no shoe or finish choice to make. If you are cross-shopping, our <a href="/blogs/buying-guides/best-ar-trigger-brands-compared">comparison of AR trigger brands</a> sets out how the main makers differ in feel and adjustment.
Orders are dispatched from the United Kingdom with £5 tracked UK delivery in 7–10 business days, and you'll get tracking by email when it ships. If a part turns out to be the wrong fit, see our returns policy or <a href="/pages/contact">contact us</a> and we'll help sort it.
7 to 10 business days from the date of your order. Every order is sent Royal Mail Tracked for a flat £5 and you receive tracking details by email when it is dispatched.
Yes. We list only genuine parts and optics from the brands shown, ordered in from the manufacturer for your order.
Compatibility notes on this page come from the manufacturer. If you are unsure, email us with your make and model before ordering and we will check rather than guess.
Yes. Bundle & Save applies automatically in your basket: 5% off when you buy 2 items, 10% off at 3 items and 15% off at 4 or more. It works across the whole range, so you can mix and match, and there is no code to enter.
Yes — you have 30 days from delivery to cancel for any reason, as long as the item is unused and in its original packaging. See our returns policy for the details.
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