Only when you need aiming. Which is mostly never. Roe deer hunting in Scandinavia or Turkey hunting in the US might be examples of exceptions.
Assuming you mean a Mauser 24/47, use the sight as you would any open rifle sight. The slider on the rear sight adjusts for range- marked in meters.
it is shotgun because the size of rifle is different than shotgun.
You sight it to a specific range , e.g. 100 meters. Clamp the rifle to a solid object, or use a benchrest. Shoot at a target and adjust the sight accordingly, until the holes in the target zero in to the sight.
To sight in a rifle without shooting, you can use a bore sighting tool or a laser boresighter. These tools help align the rifle's sights with the barrel, ensuring accuracy when you do eventually shoot.
In this order; centerfire rifle, shotgun, handguns.
Assuming that the question should read "what sniper rifle did the Germans use in world war 2" the answer is as follows: Most commonly the K98 Mauser was used, with an optical sight. Secondly the G41 semi-automatic rifle was used, designed by Walther. Also fitted with an optical sight.
You are not supposed to have a sight on a shotgun because you don't aim when shooting. You can however use a bead, black or with some color to help you. If you however look AT the bead you will be too slow. or you can use a holographic sight like the Redring sight where you don't look at the sight but keep focus on the target and still have a ring letting you see where the burst spread pattern is.
line up the target on the top of the front sight while sighting the front sight through the rear peep sight.
The only way to know is to try.
To sight in a rifle scope without shooting, you can use a bore sighting tool or a laser boresighter. These tools help align the scope with the rifle's bore, allowing you to adjust the scope's reticle without firing any shots.
any high power rifle will do the job some have there favorites to use but any rifle will work, you could use a shotgun or bow also but most people use rifles
There isn't just one good gun in mw3. There are multiple guns that you can do good with. Here are ten that you should use: 10. ACR- assault rifle 9. AS50- sniper 8. M4A1- assault rifle 7. MP7- submachine gun 6. G36C- assault rifle 5. spas-12- shotgun 4. striker- shotgun 3. MSR- sniper rifle 2. AK47- assault rifle 1. UMP- submachine gun