I have owned most of these rifles and my advice would be to avoid the XCR, Robinsons customer service is terrible. The FN 2000 is more of a tacticool arm and nearly impossible to find parts.
I have a SCAR17, the parts for it are ridiculously expensive although it is my favorite carbine. If you decide to go the SIG 556 route consider the 551 instead. While it uses more expensive magazines it is much closer to the unadulterated and proven SIG 550 and doesn't have the cheap furniture, aluminum receiver, or other issues that came with the 556.
Personally, for your intended purpose, I would suggest an AR and buy one of these other firearms as range toys.
Hk USP 45 Expert, USP 40, USP 9, SIG P226, S&W M&P9, Hk 4, Makarov, Desert Eagle 40, Beretta FS92 Centurion, Kimber TLEII 1911A1, Glock 22, SIG P225, 1943 Rem Rand 1911A1, S&W mod 64, Walther PPQ, SIG P229, Browning BDA 45 (SIG P220), Hk45, SIG P230