On a more serious note, I saw a post with some recent info from LabRadar on the date and price.
http://www.65grendel.com/forum/showthread.php?8634-LabRadar-Chronograph-Update

For light based detectors the biggest error a user can make (other than shooting the damn thing) is making sure the screens are aligned with the bullet trajectory. Any discrepancy up, down, left right, means you aren’t measuring the observed speed correctly, but a component of it.

Frankly, all commercial light based systems have base lengths (distance between screens) which are too small (they should be at least a metre for small arms) and there should be at least three sets of screens. All observing the same point in space. So, 1.5 m base length for screen set A, 1.25 for B and 1.0 m for C. C within B, and B within A, so that they all look at the same point in space.

As to the Magentospeed. It has an extremely short base length and will by subject to the same misalignment error as light screens. This causing even greater error per degree due to its short base length. As it isn’t fixed as per and muzzle brake or suppressor, there’s also the potential for gas leakage prior to bullet exit to move the sensor array. Certainly not something I would have used in my old job to measure velocity accurately, though good for triggering other things in a more robust form. Very robust versions are used on some AAA system to measure the velocity of the rounds as they are fired and pump that data back into the fire control computer.

Doppler radars are good and I’ve had some conversations with the Labradar people. The device seems to be quite a good system, though they are keeping most technical info close to their hearts. Not up to what I’ve used, but they cost tens of thousands of pounds.

Want the most accurate muzzle velocity, which is a bit of a misnomer as the projectile continues to accelerate for a few calibres out of the barrel, use an in-bore Doppler radar or laser based Doppler radar. Bit expensive though

Editor: Neil, that’s great info. And thanks for your insights on the Magnetospeed. Because the design has many advantages people may overlook some of the things you note.

Editor: Mike, we have asked the makers of Labradar to loan us a unit for testing, but they have declined to respond so far. Maybe it’s not quite ready for the market. Re the Magnetospeed, we tested the Gen 1 version. The Gen 3 version was recently released with welcome improvements. We like the Magnetospeed but we generally test with an Oehler or PVM-21 in place as well, so we have two and often three readings for each shot. We have seen some things that make us scratch our head about the Gen 1 Magnetospeed. It will be interesting to see how the Gen 3 units perform.

Plus, if you shoot on a public range, you don’t need a ceasefire to set it up or adjust it. It is SWEET!