How the airgun calibers of today came to be

by Tom Gaylord, The Godfather of Airguns™
Writing as B.B. Pelletier

This report covers:

• The 4 modern smallbore calibers
• The point I’m making
• But how did the calibers we have today come into being?
• Airguns are being developed, too
• Zimmerstutzen
• Birmingham, England, 1905

This question was asked by blog reader, Joe, many weeks ago. He wondered why the airgun calibers we have today are the sizes they are. This is an open-ended question that will never be fully answered, but maybe I can put a small part of it into perspective for you today.

The 4 modern smallbore calibers
We’ll begin by listing the 4 calibers that are currently on the market in the smallbore category. They are .177 (4.5mm), .20 (5mm), .22 (5.5mm) and .25 (6.35mm). These are the 4 we have today. But as recently as 1948, Crosman offered their CG gallery guns in .21 caliber — shooting a proprietary round lead ball. Before that, up into the 1930s, the Quackenbush company offered pellet guns that were smoothbores in 20-1/2 caliber. read more