How about an M1 Carbine for what....$500? 30 Cal ammo expensive? Just tossing another idea out there. I don't shoot 3 gun...too much time and too expensive.
I haven't seen a M1 Carbine for $500 in well over 10 years. The cost of ammo to feed it will quickly intersect and surpass the ownership cost of an AR.
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