Am I right in saying that these were the most commonly used firearms in England/Western Europe in the 1570's?

Matchlock, Wheellock (more rare) and Snaphaunce Muskets, Arquebus and Caliver

Wheellock and Snaphaunce Pistols

Does that pretty much cover it?

And can anyone give me a semi-informed guestimate about the ranges of these? Everything I've found on the Net is contradictory!

I would say you are right in regards to types.

I have used both flintlock and matchlock. I doubt there was little difference in regard to the range of these guns. Accurate range 50-80 yards for hunting. I generally get a lot closer, more like 25 yards or less. Range depending on trajectory for warfare I would guesstimate at 100-200 yards. Dropping a pumpkin sized round ball into a collection of people at 200 yards would still do a lot of damage.

As a note, Matchlocks, Wheellocks, and Snaphaunces are all firing mechanisms, not necessarily actual types of firearms. So a caliver or musket, for example, might (and probably would) have a matchlock mechanism. If you're dealing with the English, the longbow was still very much in use too and there was a lot of debate in the period as to whether guns or bows were supreme. Each had their advantages. Though not firearms, ranged weapons like bows continued to be a major player in their military and so demand consideration.

The Irish also continued to use a shortbow and the English & Scots near their border on occasion used a small crossbow called a latch.

I've done a good amount of reading into the ranges of 16th century blackpowder firearms, and I've found that the range for a musket or caliver was usually somewhere between 40 and 100 yards. This can vary depending on the amount of powder used, its quality, the fit of the ball, conditions and so on. I've read that pistols might range from 5-20 yards.

I hope this helps.

-Dan

I would recommend Gordon Frye's featured article "from lance to pistol", which gives a good introduction to the development of firearm use on horseback, and it's effects.

The typical firearm of the early 1500's was a arquebus, a medium length, matchlock piece. These fired large bore projectiles, and where used as close support for the pikemen, firing at very close range.
As their efficiency was proven, the number of guns increased. Engagement ranges, not surprisingly, increased in proportion.

As the century progressed, and armour was upgraded to deal with the new threat, the Musket appeared on the scene. The 16th-17th c musket was in effect a antitank gun, with a longer barrel and more punch, in order to take down charging heavy cavalry. Some pistols of the period also have this "high velocity" long barrel design.

Excellent!! Thank you all so much!