I use my LR for air rifles too. A micro phone set up is needed for air guns and works fantastic. I'd bet the tech from LR would recommend using one for you guys using cans.
The fact it will only register to 3900 fps is almost a deal breaker.
I wouldn't screw around with battery's, this thing eats up power. I bought their external battery from their website, or like someone else said, rechargeable batteries would work too. the external is easy and fast to set up.
Their orange zippered storage bag is pretty handy to have too.
It can be fussy finding that sweet spot as to were to have it in relationship to the muzzle brake, I had a hard time finding that spot with a JP recoil eliminator, aka JP Tank. But once i did it was dead on.
Not having it in the correct position in relationship to the muzzle, muzzle blast will cause the unit to shake and will not pick up the bullet, it will show an error message and you'll have a wasted shot.