Lubricating your spring gun: Part 1 - chambers & mainsprings
by B.B. Pelletier
I thought I would do something general that everyone needs, and this topic jumped out at me. Everyone wants to know how and where to lubricate a spring airgun. Before I begin, let me mention that this is a huge subject, so I had to break it into parts. Today, I'll do chambers and mainsprings.
We'll start with the chamber because a lot of shooters think it's the only place they need to lube. Of course, it isn't, but the chamber is perhaps the most controversial spot on an airgun.
There are a couple reasons we lube the chamber. For one thing, it lubricates the sides of the piston seal and reduces drag and friction. Friction can melt a synthetic piston very quickly. Leather piston seals are kept supple and therefore better able to compress air if they are kept lubricated.
G.V and G.M. Cardew proved that spring-piston guns burn their lubricant to produce power. That's spelled out in detail in their book, The Airgun From Trigger to Target. Anyone who has seen smoke roll out from a freshly lubed BB gun knows this is true. Of course, you want to avoid the more powerful explosion we call a detonation. Actually, a detonation is only different in how much fuel is burned in each explosion. When a spring-piston gun fires, a little of the lubricant flashes into oxidized gas, which can be called by many names such as an explosion, a diesel or a burn.
Here are the guidelines for lubing the chamber
Everything I say for rifles also applies to pistols but in smaller doses.
For guns with synthetic piston seals use a silicone lube with a high flashpoint. A good one is Crosman Silicone Chamber Oil. Use VERY LITTLE - perhaps one drop every 1,000 to 3,000 shots. Use the least with modern Diana/RWS guns such as the models 48, 52 and the 350 magnum.
For guns with leather piston seals, use silicone chamber lube in greater quantities, because it's constantly being wicked away and drying out. Perhaps, five drops every 500 shots is about right. Taploading guns with leather seals (older BSA and Hakim rifles) need even more lube than that. If you find an older airgun that has little or no compression, stand it on its butt and put 20 drops of silicone oil down the barrel. Wait several days, but periodically exercise the action by cocking and uncocking without firing, if the design permits. This often restores an older gun with leather seals.
For old BB guns, use petroleum oil and SOAK the leather seal over a period of days. If the gun has a shot tube, remove it and drop the oil down the large hole in the muzzle. It will seep through the compression chamber and into the leather seal. If the gun has an "Oil Here" hole, oil it 5-6 times with as much oil as you can get through the hole. Cock and uncock the action repeatedly to spread the oil. Be careful! Oil will run out of the gun and onto whatever it's standing on!
For Crosman M1 Carbines and model 350 and 3500 BB guns ONLY, drop the oil down the rear (the smaller) of the two holes on top of the receiver. You only need three or four drops because these guns have a synthetic poppet-type valve rather than a leather piston seal.
For more modern BB guns made from about 1955 and on, the amount of oil should be small because they all have synthetic seals. Almost all of these guns have marked oil holes.
Oil the mainspring only if the gun makes noise when it's cocked. The more expensive spring guns are lubed very well at the factory and probably don't need attention for many years. View every used gun with suspicion until you know its condition.
Spring lube is usually an oil, which is the easiest to apply. There are certain spring greases that have been available from time to time. The oils can be applied without disassembling the gun, but most of the greases require disassembly. A good oil to use is Gamo Air Gun Oil. Ten drops of oil is followed by cocking and uncocking (if possible) the gun in many positions to spread the oil as far as possible. Shooting will do the rest.
If you're going to make a mistake in the lubrication of a spring gun, it's best to err on the side of too little lube rather than too much. Guns can be ruined through over-lubrication, but almost everyone will recognize the signs of a dry gun that needs a little lubricant.
This posting will probably raise more questions than it answers. That's okay, because those questions are going unanswered right now. Ask away!