Description
The Geissele SD-3G is the S3G with a flat bow. It is a hybrid rolling break, a cross between a single-stage and a two-stage, with a shortened pull and what Geissele calls a lightning-quick reset. There is no distinct wall. Geissele rates it at 3 to 4 lb with the lighter spring or 4.5 to 5.5 lb with the heavier spring, and both springs ship in the box.
It drops into any mil-spec AR-15 or AR-10 lower with standard .154 in pins. The flat bow gives you a consistent finger position and lets you ride lower on the shoe for more leverage, which makes the pull feel lighter than the rated weight. Like the S3G, Geissele recommends it for 3-Gun competition and not for duty or precision group shooting.
Heads up: No wall means nothing to stage against on long shots. Precision-heavy rifle shooters should look at a true two-stage.
Specs
- Part number: 05-166
- Type: Hybrid rolling break, non-adjustable
- Pull weight: 3 to 4 lb (lighter spring) or 4.5 to 5.5 lb (heavier spring), per Geissele
- Trigger bow: Flat
- Pin size: Mil-spec .154 in
- Fits: AR-15 / AR-10 mil-spec lowers
- Recommended use: 3-Gun competition (per Geissele)
- Made in: USA
Who it’s for
3-Gun and multigun shooters who want the S3G’s speed with a flat shoe. Best on a dedicated match rifle that lives on close and mid-range stages.
Who should skip it
If you prefer a curved bow, the S3G (05-152) is the same trigger for the same price. If the rifle also does duty or precision work, the SD-E gives you a real two-stage wall at a similar total weight.




