Budget of around $500 maybe a little more, to go on the Ruger SFAR .308 with intentions of 100-300 yards give or take. I know little to nothing about the subject.
optics can go from $100 to $10000, it all depends upon a use case.
specifically for the SFAR the viable options would be:
1) LPVO - those go from older 1-6x to modern 1-10x.
2) most common 4-16x scope
3) longer range 5-25x.
from my shooting of SFAR i did not find it to be sub-MOA accurate, so, a higher magnification optic would be rather pointless on it. i did set mine on 1-6x vortex pst2 and it is just fine with it, as i see that gun more of a tactical than a precision shoot.
a 6x scope central dot is 1MOA in size - it covers over the 1 inch red mark on the target at 100yds distance.
rifle shoots 2-2.5MOA spread, so, you do not need, at 100yds, to have more magnification to be able to aim better.
a 10x and more will only let you see the target better, but will not improve accuracy much. still, 1-10x is what most people buy now, as it is, well, modern.
an lpvo worth looking at right now is a 1-10x primary arms. i did not see it myself, but people say it is good, better than a swampfox arrowhead 1-10x i have.
DetailsThis Primary Arms rifle scope is part of the SLx optics line. SLx optics have built a reputation for innovation, reliability, and value. All SLx optics undergo rigorous field-testing during development to best serve you in any environment.The Primary Arms SLx 1-10x28 Rifle Scope takes...
www.primaryarms.com
other decent option right now - while on sale, and cheap, would be a new 4-16x44 arken, while it is still on sale. that fits into your budget and will be very nice in that segment.
www.arkenopticsusa.com
other proven option, but in my opinion worse than arken would be a primary arms slx 3-18x. i have it too and like arkens better.
DetailsThis Primary Arms rifle scope is part of the SLx optics line. SLx optics have built a reputation for innovation, reliability, and value. All SLx optics undergo rigorous field-testing during development to best serve you in any environment.The Primary Arms 3-18x50mm first focal plane...
www.primaryarms.com
what are you going to shoot with sfar and at what distance? off hand or from the bench? are you going to hunt with it and walk long enough distances with it?
sfar is a lightest ar10-style .308 gun, to put a heavy scope on it is to defy its purpose.