I don’t know if anyone that grinded the freedom fighter event and has made it to the F-5A(G) is dealing with the same issue but the aim9L that is given stock are while on the stat card, exactly the same to the american aim9Ls, in practice they appear more sluggish, more flare sensitive and in general performing similarly to the japanese aim9p-4s (the all aspect aim-9p), i do not know if this is a airframe issue (i could see how it could be since its a slowish aircraft, although the A-10As aim9ls perform wonderfully, but i digress) a import issue or a recent nerf to the aim9Ls in general
Even so, i believe that the BR for the F-5A(G) should be reduced to 10.3-10.7 in air realistic battles at least