Not sure why people who don't know what they're talking about feel the need to comment their opinion on stuff, but here are some facts.
1. They put PM2's on semi auto Barrett 50 cals that have WAAAAY more mass slapping back and forth than a scar and they hold up fine.
2. The 5-25 model specifically is a very popular choice on air guns because of the focus distance and people wouldn't run them if they didn't hold up to the reverse recoil.
It will be absolutely fine on a Scar 7.62, huge as can be but it will hold up. A 5-20 or 3-20 US would personally be my pick for that rifle to keep it more proportionate.
There's a certain irony to criticizing 'people who don't know what they're talking about' and then laying down facts, without evidence, that don't really get at the issue here.
Both facts implicitly assume that the determining factor in scope failure is peak recoil impulse. But, plausibly, it could be the frequency of recoil, too. Even if the SCAR has a lower recoil than the Barrett, it could induce scope failure through a higher rate of recoil impacts on the internal optical components.
That, by the way, is another reason the Crane NSWC results for the MK17 might not easily transfer over to the SCAR. If the failures occurred in whole or in part due to full auto testing, then that kind of frequency of stress might be unrealistic to assume for the civilian semi-only model.
I don't really know. But more importantly,
even if this were perfectly known, I'm not sure it does the OP any good.
Any kind of comfort in this world comes from the law of large numbers. And nobody that I know of has done batch testing on S&Bs vs Vortex vs etc. to see not only which holds up best on the SCAR but also how significant that advantage is.
In the absence of this knowledge, then, it's really about prioritizing among:
* Optical feature set
* Optical quality
* Price
* Warranty/Support
If OP likes the S&B because it has better optical quality than a similarly priced Vortex, for example, then he needs to decide whether that quality difference is enough to outweigh the warranty difference (best for Vortex).
That's a choice that only he can make. For me, I usually err on the side of the best warranty support not only because I like to use my gear a lot, but because I'm clumsy, sometimes careless, and these purchases are significant expenditures that I want lasting support for many years down the line.