Well I can't find something similiar on Gamebanana and Killerfist what's your problem from Converting from GTA SA? If you don't know how you can ask Edsir because he converted a lot of weapons from GTA SA.
My PC Specs:
Intel(R) Core (TM) i5-2400 CPU @ 3.10GHz 3.40GHz
RAM: 8 GB
GFX: Nvidia GT 440
OS: Windows 7 32 bit