by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Single-stroke pneumatics
- Multi-pump pneumatics
- Other pump gun lubrication
- Precharged pneumatics
- Other lubrication needs
- Lubing pellets
- Keep the barrel clean
- PCPs differ from spring-piston guns
- What lube for your pellets?
This is a continuation of our discussion about lubricating airguns. Part 1 is basic for spring-piston seals. We don’t need to cover that material again. Today I will look at some different lubrication applications for pneumatics.
Pneumatic airguns are those that use compressed air to propel a pellet or BB. They may compress the air as they are used, such as single-stroke and multi-pump pneumatics do, or they may be guns that use compressed air from a separate source — guns we refer to as pre-charged pneumatics or PCP. I will address all three types, starting with single-stroke pneumatics.
Single-strokes are airguns that use a single pump of air from an attached pump to compress the air for shooting. They cannot be pumped more than one time. If you try to pump them more than once, the pump head, which is also the inlet seal for the reservoir, will release the compressed air from the first pump. An example of this type of gun is the Beeman P17 pistol.
Single-strokes use their pump head to seal one end of the compression chamber. Because of this they need a pump head that stays flexible for a long time. They also should not be left with compressed air in them for very long, because the soft pump head cannot contain the pressure for long. The manuals recommend no longer than 5 minutes, but that is just a guideline. You want to pump them just before you intend shooting.
Lubrication is very important for these guns, because it helps seal the pump head. It also seals the exhaust valve at both the valve seat and the o-ring around the outside of the valve body.
The pressure inside a single stroke never gets very high, so I use Crosman Pellgunoil. Daisy recommends 10-30 weight motor oil for their single-strokes, and Pellgunoil is 20 weight, so it is ideal. Lube as often as needed, which is not less than every month, or when the velocity starts to fall. A gun brought from storage should be lubricated before firing as a matter of course.
Multi-pump pneumatics are guns that can accept more than one pump of air from a pump that is built into the gun. An example would be the Benjamin 397. Multi-pumps are similar to single-strokes, except they can be pumped more than one time and they do have a reservoir inlet valve. The pump head does not also serve this function. Multi-pumps build to higher pressure in their reservoirs, but it’s still not that high. Nearly all of them, except for a few exotic British guns, can have their pump heads safely lubricated with Pellgunoil, as well. Everything else is the same for both single-strokes and multi-pumps.
Other pump gun lubrication
The other principal need for lubrication for both single strokes and multi pumps is at the flexible connections of the pump mechanism, and on the tip of the bolt. The connections have moving parts that need lubrication the same as any other moving part where two or more pieces touch. Pellgunoil works great here, too.
The bolt tip of all of these airguns usually has a tiny o-ring to seal the air at the breech. But even if it doesn’t, it still needs a drop of lube. Pellgunoil works here, too.
I am recommending Pellgunoil for all these pneumatic applications but there is no need to get anal about it. Any household oil will work well, too.
Precharged pneumatics (PCP) operate similarly to single-strokes and multi-pumps, but the pressures are much higher and they don’t have a pump mechanism built in. They usually need 2,000 to 4,500 psi of air in their reservoirs to function. At this pressure you don’t want to introduce a lubricant that is petroleum-based, because it can explode. So we use silicone chamber oil that has a high flashpoint. Notice, I didn’t say just any silicone oil. The stuff you lube door hinges with may flash (ignite) at lower pressures and is not recommended for use in an airgun. Don’t write me and ask about this lubricant or that one. I will only recommend silicone chamber oil, because I know it’s safe to use.
The oil does the same things in a PCP that it does in the other pneumatics. It gets on valve seats and o-rings and helps them seal against compressed air leakage. You also need to lube the bolt of a PCP for the same reasons as every other pneumatic, and silicone chamber oil works well here, too.
The one thing silicone chamber oil does not do is lubricate metal-to-metal contact surfaces for moving parts. Its viscosity is too low for that. So use a proper oil for that. Just make sure you don’t introduce it into the air reservoir.
Other lubrication needs
I wanted to address lubing moving parts here, but that subject is too lengthy. It needs an entire blog. So I will finish today with the subject of lubricating pellets.
This is a subject I have found to be most confusing to airgunners — especially those who do not shoot firearms and make their own lead bullets or those who shoot muzzleloaders. The confusion lies in a lack of understanding of lead and how it works in an airgun.
Lead is self-lubricating. Pure lead is very good in this respect — especially at the lower velocities at which airguns operate. Some shooters think there is a lot of friction between a bullets/pellet and the bore of the gun, but in fact there is very little friction. In black powder arms and smokeless powder arms that shoot at reduced velocities, the bullets need a grease-type lubricant to help them, but in an airgun a bare bullet is the way to go. Lubricated bullets used in airguns only slow down the velocity and open up the groups!
The same is true of lubricated pellets. They travel slower than “dry” pellets. I put quotes around the word dry because pellets come from the factory with some kind of lubricant on them. Some airgunners will clean this lubricant off their pellets, then re-lubricate them afterwards, but here is an observation I have made over the years. Most world champions do not fool with their pellets this way. I temporize with the word most, because I suppose it is not impossible for someone to lubricate pellets and win a world title. I just haven’t seen it.
I do know that lubricating pellets slows them down because I’ve tested it. Not once — many times! That doesn’t mean that it’s wrong to lubricate pellets, but you ought to know why you are doing it, and getting additional velocity is not the reason.
Keep the barrel clean
You lube pellets to keep the barrel clean. Some airgun barrels lead up unless the pellets are lubed. barrels that are cleaned often tend to do this more than barrels that are left alone. That’s why Olympians seldom clean their barrels, if ever.
PCPs differ from spring-piston guns
PCPs have no lubricant being blown ito the barrel with every shot. Spring-piston guns have a tiny bit of oil that’s blown in. What I am about to discuss applies only to pneumatics and more specifically, to PCPs. Not to piston guns.
If you shoot pellets made from lead that’s been hardened with antimony, like Crosman Premiers, and they go out the muzzle at more than about 900 f.p.s., they will probably lead the bore. Leading means lead has been ironed into the walls of the bore so tightly that it cannot be removed with just a cleaning patch. If you look st the bore from the side at the muzzle and breech, you will see dull gray streaks.
What lube for your pellets?
Everything from FP10 to rhino sweat has been recommended for pellet lubrication. Here is what I know. If a product is recommended by a lot of shooters who are known to be good, it probably works. If a product is recommended on a You Tube channel with a lot of loud heavy metal music, it probably does not work. If a product is recommended by a manufacturer specifically for lubricating pellets, it almost certainly doesn’t work. That’s been my experience. I just told you about FP10 from Shooter’s Choice. That’s a product I used when I competed in field target, and I used it on pellets for both PCPs and spring guns, alike. It isn’t made for lubricating just pellets, but it does work.
That’s it for today. Next time I will address lubricating parts that have heavy friction like mainsprings, pistons, spring guides and linkages. I’ll also address lubricating triggers, and if space permits, I’ll address lubing CO2 guns.