What viscocity motor oil is best as gun lube ?

heres how you pick a good oil for your gun.

1) go to the oil isle
2) close your eyes
3) spin around 3 times
4) point your finger out
5) open your eyes and buy the oil you are pointing at

honestly.....it doesnt make any difference.....

For internal lubrication I prefer to use white lithium grease. for external lube/rust prevent, I just use what I use on my vehicles- 10-30 or 5-20.I would stay away from really heavy oils, like the straight 50 I use in my old HD shovelhead. Whatever you were to use as far as motor oil on a gun, I can't see how it would make that much of a difference- its a comparatively simple machine compared to a vehicle motor, and a gun only "runs" when you are shooting it- unlike a motor in a car or bike, that runs continuously at high temps for hours at a time, for years.

If I am using an oil as I reassemble the gun I use a heavy oil so it will stay where I put it. Once it is together, I use a light (no heavier that 20 weight) oil so it will wick into the areas that need lubrication. All of my shooting anymore is at indoor ranges or outdoor ranges during the summer so temperature variations are fairly minimal compared to some.

MIL-DOT said:

I do realize that a warmer or colder climate is a factor, but I was hoping to hear folks' personal preferences and recommendations, and the rationale for them.

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Automotive motor oils are designed for purposes that don't have a lot in common with firearms. The characteristics they do share are lubrication to prevent metal to metal contact and that's pretty much it. For that reason almost anything will do.

You could use water, if not for the fact it would evaporate quickly. You could use transmission oil. You could use hypoid gear oil. You could use vegetable oil. You could use corn oil (after a few rounds it will smell like popcorn). You could use wax. You could use grease. Depending on its type, it will liquefy at higher temperatures and essentially become oil and you're back to the beginning. Some lubricants might burn and leave residue and filth that could be difficult to clean.

Engines are a lot more demanding and require detergent properties as well as lubrication over two separate temperature ranges: starting, which occurs at one range; and running, which occurs at a different range. That's the reason for multiviscocity oils. They have to maintain their lubrication qualities for long periods of time even after becoming contaminated.

Guns just don't have to do that, so you can use almost anything.

Honestly, I don't understand the point of this question. Use what the firearm manufacturer recommends. Anything else and you're a test pilot. But motor oil, any type, grade, or viscosity is probably OK.

In my never ending quest to find the latest and greatest lube for gun care, I've used a bunch of different stuff. Lately, I've been going old-school with Ballistol. Seems to work really well on everything. I've also tried:

M1 5w20 synthetic
Honda ATF
50% Honda ATF/50% M1 5w20
CLP
Weapon Shield
Lucas somethingoranother
RemOil
Gunslick
Gun Butter
Militec-1
Eezox

My unscientific conclusion....Doesn't make one bit of difference what you use.

Singer Sewing Machine Oil

Never could understand all the dark magic and voodoo involved with these home concoctions brewed up at midnight on the winter solstice.
$20 bucks will get you more solvent and oil than you can use in a decade.
Guns don't require constant cleaning and oiling.

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Well, they kind of do if you use them a lot. Some of us actually use them a lot. In 40 years of playing with guns all I have ever used is Breakfree CLP. Because it works.

On the vintage and delicate weapons, I use USP Mineral Oil----the kind you can ingest as a laxative. I also use this on fine edged weapons.

On the 'hardware' I go with Mobil 1 5w-20 as it's the flavor two of our vehicles use.

The M-1's get lubriplate and mineral oil.

MIL-DOT said:

(We can consider this Part II in my thread-series on "automotive lubricants in firearm applications" )
But seriously, I understand that a large number of people are fans of stuff like Mobil 1 synthetic, and I've read a wide range of preferences in viscocity, from very thin to very thick, (even up to using grease on semi-auto rails, as me and some others often do).
I do realize that a warmer or colder climate is a factor, but I was hoping to hear folks' personal preferences and recommendations, and the rationale for them.

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Although I prefer to use BreakFree LP, if forced to improvise, Mobil1 5w30EP is probably what I'd go with. It is what is in the garage right now and it works in IC engines that do more in a few minutes than what most guns will do in a lifetime.

IIRC, Armalite even had a Technical Note once upon a long time ago, that recommended Mobil1 as an acceptable substitute weapons lubricant.

Found this: http://www.stoppingpower.net/forum/topic.asp?TOPIC_ID=16727

For the last year or so I have been using Mobil 1 5w30.
For a long long time I used Breakfree LP. After a while
I would check my carry gun and it would be dry.
The Mobil 1 seems to stay wet on the rails quite a bit longer.

It's also seems to stay wet longer on my AR's. They are much
easier to clean when when the crud is not baked on the bolt.

I've always heard that automatic transmission fluid works better than anything. I have a sneaking suspicion that Break Free IS automatic transmission fluid It sure looks like it!

Mobil 1 0w40.

heres how you pick a good oil for your gun.

1) go to the oil isle
2) close your eyes
3) spin around 3 times
4) point your finger out
5) open your eyes and buy the oil you are pointing at

honestly.....it doesnt make any difference.....

Click to expand...

Bingo!!!
But if you really want to get crazy you can buy......wait for it..........gun oil.

Is ATF really that good a lubricant? Seems to me it's main purpose is a stable high pressure fluid. Aside from lubricating o rings in valve bodies and some bearings its primary function is energy transfer in the torque converter. Maybe the Readers Digest edition but there is little metal on metal like you'd find in cylinders or the action of a gun.

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X-Rap said:

Is ATF really that good a lubricant? Seems to me it's main purpose is a stable high pressure fluid. Aside from lubricating o rings in valve bodies and some bearings its primary function is energy transfer in the torque converter. Maybe the Readers Digest edition but there is little metal on metal like you'd find in cylinders or the action of a gun.

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Click to expand...

if it is mildly lubricious, it will function just fine for a firearm......hell, you could lube your gun with butter if you wanted to..

a firearm is no a highly demanding system.......low temperature, low cyclic rate and low duty cycle.......literally ANY oil or oil like substance is more than enough to lube a firearm...........hell, there are people who never lube their guns, and the guns run just fine..... lube isnt as critical as most people make it out to be.

so yes, ATF is just fine

I started using full synthetic Mobil 1 5W-30 after an extensive amount of research. After years of use, I have been very pleased.

Those who scoff at motor oil, do you really think that a petroleum company refining tens of millions of barrels of product has a special run for the infinitesimally small niche market for a particular gun oil? No, they may use different additives but there only so many base refined oils out there.

I made the same points in a previous oil thread but ATF continues to be the primary ingredient of the secret sauce promoted so often. Just pointing out that ATF is probably not that great of a lubricant. 3in1 likely exceeds its abilities.

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Q: Why doesn't everyone use generic motor oil in their cars?




A: Because the additives make the base oil better.

Semi-auto pistols have momentary high pressure loads on the rails. Most gun oils contain a high pressure additive package and that's one of the things that makes them different from motor oils.

In automobiles, high pressure additives are normally found where gears mesh because the momentary loads on the gears between the teeth create momentary high pressures especially when the vehicle is starting to move from a dead stop.

This is what you have to understand about guns - although the cycle rate they run at is far lower than an automobile, there are some things going on with the pressure points like the rails on a semi-auto.

Smoothly finished surfaces are really rough and irregular at a microscopic level. When the two surfaces are brought in contact with each other the asperities (high points) between the two surfaces are in contact with each other rather than the entire bearing surface.

If there is no lubrication, under loading (recoil), the asperities are touching along the surface and deform until the real surface needed to support the load is created. Under such conditions, small irregularities on the sliding surfaces cause localized flashes of high temperature (570F - 1850 F), without significant increase of the average surface temperature.

If relative motion is introduced adhesive wearing (galling) may occur through shearing of the interface oxides protective to the base metals followed by asperity contact and welding of the base metals by pressure with the weaker metal yielding under pressure; or, welding of the base metals from pressure with a weld junction forming that is stronger than either of the base metals causing wear to take place on both surfaces that are in sliding contact.

Galling is defined as the "wear by transference of material from one surface to another during relative motion, due to a process of solid-phase welding."

(Solid-phase welding is welding done through friction or pressure and without the use of a filler material.)

At high stresses, the surfaces may seize and freeze-up after only a few cycles of movement between the mating surfaces.

So what you're trying to prevent in your gun is contact between the asperities and high temperature flashes that may result in galling.

There are some other features that gun oils should have such as resistance to oxidation as guns are often lubricated and then stored.

Most motor oils will provide the boundary lubrication needed to prevent galling but they aren't very good about resisting oxidation. If you use motor oil, and you've stored your gun for 2-3 weeks without use, put a couple of drops of fresh oil on the rails before you shoot it to ensure there is enough oil on the rails to create the boundary layer between the metal surfaces.

^^^^^This^^^^ is what I like about THR.


When you change the oil in your vehicles...drain that last little bit out of the containers your oil came in. More than enough for your gun use until your next oil change.

Most motor oils will provide the boundary lubrication needed to prevent galling but they aren't very good about resisting oxidation. If you use motor oil, and you've stored your gun for 2-3 weeks without use, put a couple of drops of fresh oil on the rails before you shoot it to ensure there is enough oil on the rails.

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I agree with the first sentence, though even the worst of oils will protect guns from oxidation if kept in reasonable conditions. For long term storage, there are better options. As to adding oil after two or three weeks, I've purposely stored and not used a gun for six months. The rails were still lubed and the gun operated fine.