Airgun calibers and cleaning
by B.B. Pelletier
Reader JW asked for this post. Before I start, let me remind you that airguns usually do not need to be cleaned. They don't get dirty in the same way firearms do, so cleaning is reserved for when accuracy falls off.
Here's the question:
I was getting ready to clean the bore of my air rifle with J.B. Bore Compound but was having trouble finding a rigid cleaning rod for an air gun in .22 cal. (I'm not much on the flexible rods.) I was wondering if it would be safe to use a cleaning rod for a .22 rimfire?
What's different about airguns? Starting with .22.
Calibers! The .22 caliber airgun is 0.218" in diameter rather than 0.223". When makers of cleaning equipment make bore brushes, mops and patch holders, they make them for the large (and to them more common) firearms dimensions. Fortunately, the size difference is usually too small to matter, but with custom-made cleaning equipment there can be problems. Some makers of cleaning rods get anal about bore-fit, and I have seen .22 rods that were too large to fit in a .22 airgun bore. I've also encountered a FEW patch holders that were too large. The makers of these tools believe that there should be as little clearance as possible between their tools and the bore in order to prevent scraping one side of the bore with the rod through careless cleaning techniques. In effect, they're using the top of the rifling as a bore guide - but only in rimfire, as an airgun bore has far less space.
In .177 caliber, the situation is reversed. Seventeen caliber in a firearm is exactly that. Airguns are .177, which is close to .18 caliber, so they are LARGER than the firearm equivalents. This time, the problem isn't as serious. The firearm equipment is all smaller, so the brushes don't fit as tightly but that's the extent of the problems.
There are far fewer .20 caliber firearms, so most folks use .22 caliber equipment if it fits. If it doesn't, .177 can be used. Brushes can be a problem - not with finding them but with finding brushes that attach to the rod that fits the bore of your airgun.
There is LOTS of .25-caliber cleaning equipment available for firearms. And, for your information, the airgun caliber is NOT standardized. Modern .25-caliber airguns have smaller bores than vintage guns - especially those from BSA and Webley. By vintage, I'm talking about the 1950s and earlier, not the 1980s. The difference in bore size doesn't matter as far as cleaning equipment goes - just pellets, but it's useful to know.
I buy my cleaning rods to fit firearms and I haven't had a problem yet. Just be cautious when buying handmade benchrest cleaning equipment.