S1 and S2


Skill Level
Amateur/Hobby Shooter
Sep 9, 2019
491 Posts
380 Helpful Votes
6 Best Q&A Answers
Let's look and compare two key data-points SCATT provides: S1 and S2. The first one, S1 represents the average speed of your Aimpoint during the set control interval (1 second before the shot by default), and the S2 tracks your acceleration in the last 250 milliseconds.

Aside from the actual trace line interpretation, these parameters are the best gauge of shooter's hold stability and trigger work. An important benefit here is that S1 and S2 add a numeric value to these shooting skill components. This allows performance tracking over time and the ability to compare with other shooter's data.

If we take a look at the image on the right, we see a less than perfect shot where the S2 is greater than S1, which indicates an acceleration spike preceding the shot. The timeframe of the S2 parameter (250ms) corresponds to the trigger stage of the shot. So if your S2 is higher than the S1, it may be a sign of a trigger jerk.

When it comes to the image on the left, however, S2 drops in comparison with S1. The shooter retains focus, hold stability remains solid in the last fraction of the shot, and the triggering doesn't cause an acceleration of the Aimpoint.

In a nutshell: the lower these two are - the better. However, the correlation between these two numbers is equally important. Ideally, you want the S2 to be equal to or less than S1

Comparing values from shot to shot can also be beneficial. Slower Aimpoint speeds at the beginning of the session are good, yet if the S1 parameter keeps increasing as the session progresses it may be a sign of overall fatigue, a series of delayed shots, etc.

Since this is a simple numeric value, comparison with teammates or top shooters in your discipline can offer additional insight.

Take into account that the S1 has a strong correlation with your gun’s weight (the speed of your trace decreases, as the gun’s weight increases). But this is a slippery slope since hold stability will progressively suffer as you are using heavier guns. Your hold will become smoother, yet the gun will swing with a far greater range of motion. This aspect should be approached individually.

There is no universally perfect value for S1, but generally good numbers for reference are as follows:

50m rifle:
Standing: below 50 mm
Kneeling: below 45 mm
Prone: below 40 mm

10m Air Rifle: below 10 mm

Air Pistol: below 100 mm
Skill Level
Amateur/Hobby Shooter
Primary Discipline
Small-bore Pistol
SCATT Experience
3 years
Mar 11, 2020
19 Posts
11 Helpful Votes
1 Best Q&A Answers
Can anyone tell me the value for S1 while shooting 25m precision pistol?