Better yet would be a whole gearbox replacement.
A SystemA M130 might do the trick. YOU WILL NOT BE ABLE TO RUN A HOT GUN ON ANY FIELD.
1) Snipers usually have to pass a "sniper course" (which chances are you don't have)
2) They usually have to have lots of experience (something you also don't have)
3) You must have your gun pinned to single shot or bolt action (your gun is capable of full auto)
4) That's not a "sniper rifle" by any means at all it's an assault rifle. If it were an SPR then yeah I could see that but it's not.