Down the rabbit hole

 Saw you saying that have a Gamo magnum.

It doesnt brake the glass, it shakes the internal parts loose like the cross hairs and the focus and will not hold on zero. you should check if the scope is air gun rated or not. the recoil from the piston is very hard on scopes and even more so on the low end quality guns. You get what you pay for.

Probly not a silly idea. A spare scope is always handy in case one fails.
I kept my gamo scope, and are using on 1322 till I can afford another one, after the gamo killed the $300 gun City air rifle rated one I put on it.

Do you spend any time researching stuff?
A rifle scope has moving parts in it.
Those moving parts are made to take recoil (you know the unbelievable recoil of your umerex)
In a powder rifle they are made to take a backwards recoil, because that is all a powder rifle has, backwards recoil into your shoulder.
In a spring or gas ram air rifle there are two types of recoil, a forward one as the piston hits the end of the cylinder and the backwards one like a powder rifle has.
As a powder rifle scope is only made to take the backwards recoil and not the forwards recoil, this means if you put a powder rifle scope on on a spring or gas piston rifle everytime you shoot it, it will get a jolt forward as the piston hits the end of the cylinder, which the scope has not been made to take. This will eventually shake the moving bits inside and they will come loose. When this happens the the cross hairs will move and won't be where you set them too. You won't hit where you are aiming because they have moved.
In an air rifle rated scope they know that there is a forward and backward shock to the scope, so they make the moving bits in the scope to be able to take the forwards and backwards jolt that happens in a spring or gas piston air rifle. This means that the moving bits in the scope don't shake loose and the scope stays on target.
Thats a very basic description.
Get on the Internet and look it up.
Guns like the gamo magnums have a very heavy recoil and are known to break (shake the moving bits loose) scopes that arnt well made even if they are for air rifles .
Before you ask, an air rifle rated scope can be used on a powder rifle.
It is not a good idea to use powder rifle scope on an air rifle.
Pcp and pump up air rifles do not have to use a air rifle rated scope as they do not have a big heavy piston crashing into the end the cylinder when firing a shot. So that don't have the a big forward jolt like a spring or gas piston.