@taliv : It looks like the E-target you used was the Shotmarker brand engineered by Adam McDonald of Autotrickler fame. While they are a full two steps above the target camera systems that have come on as of late, they are considered an entry level E-target priced at around $850 USD. Their margin of error currently falls outside of the ISSF required <1mm, and are rated at a 4-5mm error window. They use a color coordinated set of microphones attached to a flat target frame. Other than the target facing itself, they are relatively maintenance free (until someone shoots a network cable). The standard chamber type E-targets (SIUS, Megalink, Kongsberg, etc.), can accumulate small bits of chaff created by bullets passing through the target face, and require simple but regular maintenance. The nice thing about the Shotmarker, is that it will give you a velocity report for each shot. This is great for being able to know when a watermark '9' was due to a bad bullet, or shooter error.