Not a chamber sighter, but I got two different bore sighters off Ebay for $12-15. They are better than the old Bushnell one I was using. The Bushnell could not be adjusted, and was off. These ebay ones you can align the laser if it ever needs it.
I have sighted in 3 guns with it so far. All have been about 1/2" off @ 25m, some minor adjustments and I'm bang on in about 3 shots or less.
There are many vendors. Seems like two versions, one is .22-.50, the other .17-.78. I say spend the extra $2-3 and get the .17-.78
Photos from Ebay.