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whm1974 · Veteran Member

OK after searching on more info on airguns, I ran across "Dieseling", where flameable oil or lube will combust shooting a pellet much faster then otherwise.

If I brought a spring-piston airgun I don't want to be doing this. It would dangerous and most likely damage the gun. So how do I prevent it?

radar · Silver Status Member

Regarding dieseling in spring-piston air guns: Most of time if you buy a new spring piston type airgun, especially Chinese made, which covers most of the off-the shelf guns out there, it is oiled excessively inside to prevent rust in storage and shipping. They will normally diesel for a while, at least the first several shots. Typically, it doesn't go on long enough to really hurt them or else everyone's rifle would fail in warranty.

The biggest issue with it is that is dirties the barrel with soot pretty soon and accuracy falls off during break-in until it is wiped out of the bore with Goo Gone or something. (Good to clean the new barrel before ever shooting it, too.)

After a while, you'll probably notice just a little oil smoke hanging in the barrel after shooting. This part is probably just normal and ongoing combustion of the thin oil film inside the compression chamber, and is not really destructive like the true detonation of dieseling.

The only thing you can do to prevent a new gun, or an over-lubed spring gun, from dieseling is to disassemble and clean it. This requires some knowlege and a spring compressor to do safely. The outside the compression chamber area are lubed with a very small amount of 60% "moly paste" or some people use a little white lithium grease or something. No oil can be in the area in front of the piston or in the chamber area, or on the pellets.

If you do any of this, be sure to look up "lube tuning" to get some tips.

robert w · Senior Member

never put oil in the chamber unless its an older gun with leather seal on the piston. it you get 1 of those ,no oil will kill it fast but radar is very correct on newer springer guns

whm1974 · Veteran Member

Thanks guys. I'm reading that some people do this on propose by adding a drop of diesel fuel or oil in the base of a pellet to make it go faster.

Isn't this a dangerous thing to do?

radar · Silver Status Member

The oil in the pellet in front of, instead of inside of the compression chamber is probably not as harmful to the gun itself, but I'm just guessing.

Is it dangerous? It almost certainly is, and even in all sorts of ways I haven't even thought of yet. Don't do it.

Accurate? Not if the pellet breaks the sound barrier and tumbles wildly.
...No reason to abuse the gun like that anyway.

whm1974 · Veteran Member

Don't worry I wouldn't do something that stupied.
The gun might fly apart on me.

Of course this assuming I'll be getting a spring-piston rifle to begin with. I may just stick to CO2 and pumps.

But thanks