I think this question may have been asked before but my search of the site did not find it.
Has anyone ever used a MagnetoSpeed Ballistic Chronograph with their double rifle?
It is barrel mounted; directly strapped on the barrel of the weapon, with the sensor hanging out in front of the gun.
http://www.magnetospeed.com/pages/reviews-testsI am unsure of their accuracy. The price is 2 1/2 times ($275) of a normal chronogragh. I am not sure if attaching something to the barrels as it requires won't change the handling and shooting somewhat. It does seem to elieminate the I shot my chronograph issue for idiots like myself.