First things first, they have identical seekers, so in that regard, there should be no difference, they are equally affected by MP.
As for why there might appear to be a difference then my guesses would be:
R-77-1 have a larger warhead than AMRAAM, meaning that near hit explosions will do more damage, including those that impact the ground below if the target is flying very low, though they do also have a smaller prox fuse radius (10m vs the AMRAAMs 12m)
Much faster Time to target. R-77-1s are much faster, leaving less time for the target to react properly
Su-30SM has PESA radar, this provides far more updates to the missile than any M-Scan, meaning an Aim-120 guided by M-Scan has a lower chance to impact than an Aim-120 guided by AESA/PESA radar.
User error. There is many ways to mitigate MP, so if your AMRAAMs are failing to hit but their R-77-1s seem to be hitting you, then you might need to adjsut what you are doing.
Hmm… Neither aircraft you can truly max out the Aim-120 with, being slower platforms. Now Ive not played either, but Id sit around 10k ft and fire at around 15km with the A/B and 20km with the C5s (this is how I operate in the Tornado F3 Late) . Try and max out your speed as much as possible, if the target is flying low, firing the missile upwards slightly might help too. The key is to get the missile to come down at as steep of an angle as possible.
Yep and also should be a lot harder to chaff. The narrower beam means that the Missile is less likely to be able to see the chaff, perticularly at longer ranges
I mean, so. Yes they have the same seeker. But fun fact, they aren’t effected by multi-pathing in the same way.
So, something most people dont realize, multipathing is kind of aspect dependent. Not the same way it is irl, but basically since its projecting a lower position of the target, it moves where the missile is leading to. And in most front/side aspect shots, a lower proportional value makes it less severely impacted.
And the R-77-1 has a much lower proportional value to aim-120s, which does actually make it moderately more likely to splash targets. Especially combined with the larger warhead as you said.
Like its not a massive benefit, but it is actually better at hitting multi-pathing targets.
Soviet was a super power with an actual tank dev and building industry same goes for their Mili plane. China being closed to , surprisingly , both west and east for a good while leading them getting a lot of tech and with a large country and man power. They can easily develop their own tech.
And they export their arms so lol ?
Not to mention their tech tree actually get boosted by Taiwan since they get their tech from the west.
Same can be said for the US but the thing is NATO nation in game tend to have their own stuff along with some more from US themself.