AR-15 Geissele SD-E Trigger – Full Review

Some may choose to drive a Honda while others may choose to drive a Mercedes. Either of these vehicles will get you from point A to point B by the use of four tires and an engine. However, the Mercedes will generally look nicer, will have more options, will have a smoother ride, and will also cost more money. In my case, with my home built AR-15, I felt like I had the Mercedes of triggers when I got my hands (or trigger finger, in this case) on the Geissele SD-E from Geissele Automatics.

Out-of-the-Box Impressions

Upon opening the package, the first thing that caught my eye about the SD-E trigger was the flat trigger bow. Personally, I had never seen anything like it before. The completely flat trigger face and the aggressive angle of the rear of the trigger gave the Geissele SD-E an aesthetic appeal for me. It was something different to set my rifle a part from others.

Secondly, I noticed the finish. It appeared to be flawless and was a deep, dark and glossy black color. Then I noticed the shape of the hammer. It was thinner and smaller than a normal AR-15 hammer. I suppose I might as well just describe the rest of the details and features of this trigger system, shouldn’t I?

Features

A Geissele Super Dynamic – Enhanced (SD-E) trigger is essentially the same trigger as a Geissele Super Semi Auto – Enhanced (SSA-E) trigger; the only difference is the physical appearance. Instead of a M4 bow, or curved trigger shape, the “Super Dynamic” series of Geissele triggers has a completely flat trigger face. When I spoke with the owner (and inventor) at Geissele Automatics, Mr. William Geissele, he stated “there are other small differences between the SD and the M4 bow style triggers, but for all practical purposes they are the same.”

My Geissele SD-E is a two stage trigger with a total pull weight of approximately 3.5lb. The “E” in SD-E stands for “Enhanced” trigger. When shooting, one will experience a lighter total trigger pull weight, while also experiencing what Mr. Geissele refers to as “the break of a candy cane” on the second stage.  The best way I can explain what it feels like to shoot is as having a smooth, sharp and crisp trigger pull. I have not before experienced a trigger pull like the Geissele SD-E. Every pull felt exactly the same as the previous.

My Geissele SD-E trigger also came accompanied with a Geissele designed AR-15 hammer. This hammer was noticeably thinner, lighter, and smaller than a typical “mil-spec” hammer. To quote Mr. Geissele again, “each Geissele hammer has been designed to strike the firing pin in the ‘sweet spot’ much like one would find on a golf club face when hitting a golf ball.” When shooting my AR-15, the hammer did reset noticeably faster than my previous mil-spec hammer. This allowed me to shoot quickly, despite the fact that the SD-E is a two stage trigger.

Rather than being manufactured from carburized 8620 steel like a mil-spec trigger would be, my SD-E is manufactured from S7 shock-resistant steel. While doing some research, I found that S7 shock resistant steel is the same steel used in jackhammer bits.

Installation

Installing the Geissele SD-E trigger and hammer was no different than installing a mil-spec trigger and hammer. If you have never installed a trigger or hammer in an AR-15 before, please do not hesitate to check out my installation how-to article here, or my video here. I also have an installation how-to video specific to the Geissele SD-E here.

I, like many others out there, had KNS Precision Anti Rotating Pins for my hammer and trigger pins. To install a Geissele trigger properly, you should use the supplied Geissele trigger and hammer pins. As Mr. Geissele informed me; “Anti rotation pins are soft and the wrong size. Soft pins can pull burrs and jam the trigger up.”

He offered me some additional advice for installation: “Lube is your friend. Be liberal with your application of grease and oil. Don’t worry about cleaning the trigger a whole lot. The best feeling triggers are those which are lubed and rarely cleaned. The oily powder residue acts like a burnishing compound/solid lubricant.”

Range Performance

If you watch my range review video above, you will see that I feel that my Geissele SD-E trigger has helped increase my overall accuracy by removing almost all shot anticipation. The SD-E is a two stage trigger, so I know exactly when the trigger is going to release the hammer, and I decide when it does.

Overall Assessment

The Geissele SD-E trigger has a MSRP of $250.00, and it fulfilled my expectations for a trigger of that price point. In evaluating the Geissele SD-E trigger, I couldn’t find a flaw in form or function. I appreciate the aesthetics of it, the ease of installation and the overall feel and function. The pull is better than any mil-spec triggers I have shot and I prefer the SD-E to the MEGA trigger I had before it.

There is only one personal question I have to ask myself after shooting my Geissele SD-E. Now that I have driven the Mercedes, will I ever be able to go back to a Honda?