HELP !! weapon hack m14ebr lagynies

I hope your reading this because i need your help. I was using a wonderful hack the one got patch or detected.The hack was awesome and the hack included a weapon hack.(m16 to m14ebr)
The m16 change to the m14. Well here is my problem i have 2 pernament m14ebr (the real one) everytime i play with it lower my fps. I have no idea why it does that.i remember playing with it with no lag. Please help me . i try to fix it but it wont work.i unstall the game twice still doesnt fix. please help! I remember playing m14ebr without the lag but now i lag with m14ebr........ -_-