1. Using a sandbag, set up your rifle so that it doesn't move around much.
2. Aim the air rifle at a target using the iron sights.
3. Adjust the windage and elevation of the scope until it is pointing at the target while the iron sights are pointing at the same target.
4. Try it out, see what happens. Fire three shot groups and adjust based on the center of this group.
Only if the scope is designed for an air rifle. Because of the recoil being different on an air rifle than a firearms rifle. Air rifle scopes are made differently than firearms scopes. A firearms scope can break it's glass mounts if it is used on an air rifle.
Almost any air rifle scope will fit a Daisy. Check Walmart or a sporting goods store for a Daisy scope. But any air rifle scope should fit the dovetail mount that is on the rifle.
Some scopes can cost more than the Air Rifle. Leapers makes some excellent scopes for around $250. Whatever scope you purchase make sure it is designed for air rifles. Air rifles, because of their forward / reverse kick, can break a regular hunting scope not designed for this type of rifle.
Yes it has an 11mm Dovetail scope mount
If it has a scope rail or grooves for a scope mount then yes it will support a scope but you may need a scope stop to keep it from moving.
Only if the scope is designed for air rifles. Regular firearm scopes are made different than air rifle scopes and many will break if used on an air rifle because the recoil is different than a firearm.
A scope for an air rifle can be bought at many different places. You can buy one in a gun shop, in a sporting goods store, or even in a pawn shop. You might be find one for sale in your newspaper.
One that was designed for air rifles. Best will be determined by your intended use and how much you spend.
A rail interface system or a mount on the top
I am not familiar with this particular model (427) but I am familiar with Benjamin air rifle. If your problem is that there is on Scope rail to mount your scope then I know how to fix it. Crosman airguns owns Benjamin air guns. Crosman offers a special Benjamin barrel clamp that lets you mount a scope to it. See the link below
Could it fit? Yes. Good idea? No. Air rifles need a scope with a different internal design, since the recoil is different, and can be in a different direction. Scopes made for firearms may fail when attached to an air rifle.
It depends completly on which scope and which airsoft gun. Some may work well and others may just be for show.