it has to do with some properties that you can change in nifskope, I've had this problem before. I cant currently open nifskope but it has to do with the unknown properties. not sure what each of them are but there should be a rollout menu for "unknown" either under the trishape or the material. there should be like 8 spaces and yours probably all say 0 when they should say like 2, .25, .75 ... open up the baseball helmet in another instance of nifskope and just copy the same values it has.