I haven't built the Sig Hog Bipe yet, it's still in the box. However, if they are the nylon push rods that are in the Sig Something Extra, I used the outer sleeve and ran 2-56 steel rods through them. I have had nylon rods on my Sig 4*60 and always had problems with the temperature changes. I was always re-trimming. I also removed the nylon inner rod on the 4* and used replacement steel.