Wolfmann this is the same principal for registering the bullets that CoryT, KnS Ballistics (myself and another member here), and Applied Ballistics (Bryan Litz) have used for long range bullet testing. However, this unit does not provide enough distance between the microphones to give any "lag time" to indicate ballistic coefficient. The purpose of the chronographs are inherently different.
As compared to a MagnetoSpeed, this acoustic method has a distinct "pro" but several "cons" in comparison
The pro being that if you want to shoot lead bullets over it, the machine will still pick it up and the MagnetoSpeed is going to have a lot of trouble if not downright fail.
Cons being:
Subsonic ammunition is fussy and unreliable for getting accurate numbers
Alignment, like all light based chronos, is critical
Muzzle blast may or may not screw with the acoustic sensors in this one depending how far away you are, caliber size, etc.
Compared to the magnetospeed (which I personally have been VERY happy with)
Once basic alignment is setup on the gun it can be shot with for many many rounds at any attitude or location and the magnetic hall effect sensor approach will give reliable readings for any cupronickel or ferritic component bullet. Lead is, as mentioned above, a hit or miss item.
Subsonic ammo with jacketed bullets work without issue on the magnettospeed
Neither of them do archery or air rifles well. BB guns on the magnetospeed seem to work but those are steel BB's, precision lead pellets don't work no matter what I do with the settings.
Considering the difference in price tag, about $25, I'm more inclined to keep my MagnetoSpeed V2 than to go with this unit for precision rifle work. For pistols, ehhh... I have an old Chrony that does arrows, pellet rifles and pistols equally well and registers to +/-0.5% error so for something going <1000fps that's pretty darn close.
