Originally posted by The Toyman
urathane orings are the milky looking ones you use on your tank. I have never seen a urathane oring that was not as stiff as a tank oring. They would not work on any moving parts in any gun because the oring does not have enough give. By the time you got a urathane oring to seal the bolt would be so stiff you couldnt move it. Has anybody else seen a black urathane oring. They are probably Viton orings rather than urathane.
Correct me if I am wrong.
I have seen plenty of 'spongy' urethane o-rings. I have also seen the stiff kind.
They do have urethane O-ring kits for the Matrix and they are around 25 bucks I believe.
Viton orings are in the gun from the factory. Buna are the replacement ones that Aardvark sells along with the urethane ones. One set is cheaper than the other.