When we started making our covers we made them to the exact length of the can.
After the cover "broke in" and the inner liner compacted over time it would allow the front to extend past the muzzle of the can and get frayed from muzzle blast. We addressed this by making the covers 1/4" shorter than the can so that when the cover is used over time it will come to within about 1/8" from the muzzle. Since we did this the reports of frayed muzzles has dropped way off.
Also, in some instances on some models of our covers that have the inner material somewhat exposed on the ends, the material is simply worn away from abrasion in packs, bags, etc and can expose the white fibers on the inside of the black inner material. This has happened to mine at times and I simply trim it off with scissors and drive on. If yours is doing this, like I've said many times, we have a lifetime warranty on our products, and you determine the life of the product, even if you destroy it through your own negligence or misuse. If you feel like you haven't gotten your moneys worth we'll do what we have to do to make you a happy customer.
When talking about TAB GEAR and AG, we were here first.