As an aside I just received one of these (large for 21) in the mail yesterday, I intend to replace the synthetic grip-cap on my model 21...they shrink over time.

I purchased 1000, 2500, and 3000 grit emery today so that I can get in to the job when we get back from Queensland.

Link.
[Linked Image from usedguns.com.au]

These are my opinions, feel free to disagree.