[Sibil]

My gunsmith use a "thing" that is put in the barrel to align the scope, What is the name of that thing? Thanks for advance.

[rhyno13]

laser bore sighter. Don't forget you need to zero out the scope first.

[TCH2FLY]

An optical bore sight tool is called a collimator

[locutus]

Tch is correct. It's a collimator. Laser bore sighting devices are normally inserted in the chamber.

[Sibil]

Im trying to find one which is the best high quality (without considering the price) and what is the best medium quality (considering the price)?

[TCH2FLY]

Originally Posted by Sibil

Im trying to find one which is the best high quality (without considering the price) and what is the best medium quality (considering the price)?

There are those who feel the only "real" bore sighting is pulling the bolt and aligning the scope and target that way.
I use a cheap laser bore sight tool that slips in the barrel and serves me very well.
To mount a new scope I used a level, feeler gauges and a plumbob to place it level in the rings and level the reticle, then the laser to do a quick alignment for windage and elevation (based on the caliber) which puts me very close at 100yds (something I don't the "traditional" method does very well)

[Tenderribbs]

Just get a designated 223 bore laser put it in just like a Shell and allign your scope they are cheap accademy sports has one that I use for 25 bucks just get extra batteries they eat them up.

[JonM]

the reason smiths use collimeters is because its fast and easy to use in limited space like a gunroom.

i prefer traditional bore sighting. its free. i dont do a LOT of bore sighting so i see no reason to pay for something i can just do in a few minutes of work and lining up on something in the backyard or at the range.

[Halwg]

Just ask for one of those bore "thingies". Any gunsmith worth his salt will know what you mean.