BZ,
Yep.
I missed this when first posted.
I would suggest you look at some links posted in this section and read a good bit about matchlocks, before deciding.
Saying matchlock is a bit like saying "car'.
They came over their times-pan, from short and small, to heavy and short, to long and huge and everywhere in between!
Here is a link to an early one. If you search the site in this link, you will be up to your eyeballs in matchlocks of all sorts!
http://www.vikingsword.com/vb/showthread.php?t=7542&highlight=tinderlock
Good luck and keep us posted!
Flint,
Your post appeared whilst I was replying!
I would just say though that some of the early harquebuse' had bores of about 14mm, or about .55 calibre.
This was very common on guns from the first half of the 16th century.
The short guns were at this early date not cavalry weapons, but those of the Landsknechts, who fought on foot.
The "short" was just a fashion, and appeared in many things, from candle sticks to chimney pots!
Best,
Richard.