A burr on your release calipers does not have to be very large at all to cause loops to wear quickly.

One means to check them is to take a Q-tip and fluff up the end so the cotton is nice and loose. Open the jaws of the caliper and rub the cotton over them. Anywhere the cotton snags, you have a burr.

For removing the burr, I have heard of people taking a piece of loop material and rubbing some fine lapping compound into it then running the release up and down to smooth out any burrs.