Mobil 1 synthetic makes a fantastic gun oil. (Caution: Geek Stuff.)

[benEzra]

Most gun oils are just regular machine/motor oils with off-the-shelf additive packs (just like those oils), packaged in tiny quantities with the word "gun" on the bottle and a 500% markup. After trying a bunch of specialty gun oils for years (mostly Rem Oil and Hoppes Elite), I've found something that lubricates better, fights corrosion just as well, doesn't evaporate as easily, and is way cheaper.

Turns out that Mobil 1 synthetic motor oil (full synthetic, not dinosaur derived) actually has superior properties compared to most gun oils--less volatility, better lubrication and wear resistance, higher shear strength, and better temperature stability.

All the info below (in gray) is from the user Gun Slinger from the High Road, and is posted here with his permission. He recommends M1 synthetic 20W50 for most uses, but AR's might be happier with 10W30 due to the tight clearances and relatively low-energy bolt carrier. But even 10W30 is way superior to most gun oils. I don't have any 20W50 yet, but I had some extra Mobil 1 10W30 that I had bought for my car, and recently started using it on my civvie AK and my S&W Ladysmith 9mm, using a Q-tip as an applicator to the bearing surfaces. Results have been excellent; the guns work more smoothly, and the oil doesn't dry up/evaporate as quickly as the oils marketed as gun oils.

Note that this info probably applies to most synthetic (polyalphaolefin based) motor oils, but is NOT necessarily applicable to non-synthetic oils (i.e., regular motor oil).

Comparison to a traditional gun oil:

RemOil usually hovers around the 25 cSt (give or take) level at 100 F and really thins quickly as it is subjected to heating. The (Mobil 1 synthetic) 10W30 starts at 62.0 cSt at 100 F and thins to 10.0 cSt at 212 F and if memory serves it also has a higher VI than RemOil and that is why it seems to stick around longer than the RemOil.

So Mobil 1 appears to kick Rem Oil's butt. It also appears to kick Militec-1's butt, though by a smaller margin (the stats for Militec-1 are the last entry in the table). And that is a very highly regarded gun oil.

The only caveat would be, if you take the gun in a very corrosive environment (salt spray, or two weeks of camping/hiking in a humid area, or whatever), a corrosion protectant/lubricant like CLP might be slightly better at preventing rust (M1 has oxidation inhibitors, but it is optimized as a lubricant). Still, in those conditions, a dedicated corrosion protectant like Boeshield T-9 or Corrosion-X sprayed everywhere on the gun, with Mobil 1 just on the bearing surfaces, might be even better than CLP all around (corrosion protection and lubrication wise). Something to think about, anyway.

Since Mobil 1 is subjected to such extreme conditions (in terms of thermal stress, oxidation and pressure) inside of an internal combustion engine, it appears that it should possess both adequate film and barrier strength to serve as a small arms lubricant.

The criteria that these lubricants were evaluated by are:

1. Pour Point (P/P): The lowest temperature (in degrees F) at which the lubricant will flow within a specified timeframe.
Minimum requirement: -50 F

2. Flash Point (F/P): The lowest temperature (in degrees F) at which the lubricant will produce vapors that, if subjected to an ignition source, will ignite and combust.
Minimum requirement: +450 F

3. Viscosity at 100 F (V/100): The viscosity (in centistokes) of the lubricant at 100 F.
Minimum requirement: 40.00 cSt

4. Viscosity at 212 F (V/212): The viscosity of the lubricant (in centistokes) at 212 F.
Minimum requirement: 8.00 cSt

As a point of reference, the kinematic viscosity of pure water at:
68 F (room temperature) is 1.004 cSt
100 F is 0.658 cSt
212 F is 0.294 cSt

5. Transient Operating Range (TOR): The sum of the absolute values of the Pour Point (P/P) and the Flash Point (F/P).
Minimum requirement: 500 F

6. Viscosity Index (VI): An arbitrary numerical value assigned to a lubricant indicating its ability to retain its viscosity across a specified temperature range.
Minimum requirement: 110 (Very High)

Low VI: 35 or lower
Medium VI: 35-80
High VI: 80-110
Very High VI: 110 or higher

Data for Mobil 1 Synthetic Lubricants:

0W20
P/P: -70.6 F
F/P: +449.6 F
V/100: 43.0 cSt
V/212: 8.4 cSt
TOR: 520.2 F
VI: 176

0W30
P/P: -65.2 F
F/P: +456.8 F
V/100: 63.1 cSt
V/212: 11.0 cSt
TOR: 522.0 F
VI: 169

0W40
P/P: -65.2 F
F/P: +456.8 F
V/100: 80.0 cSt
V/212: 14.3 cSt
TOR: 522.0 F
VI:188

5W20
P/P: -52.6 F
F/P: +442.4 F
V/100: 48.3 cSt
V/212: 8.8 cSt
TOR: 495.0 F
VI: 164

5W30
P/P: -65.2 F
F/P: +446.0 F
V/100: 64.8 cSt
V/212: 11.3 cSt
TOR: 511.2 F
VI: 171

5W40
P/P: -49.0 F
F/P: +438.8 F
V/100: 102.0 cSt
V/212: 14.8 cSt
TOR: 487.8 F
VI: 152

5W50
P/P: -65.2 F
F/P: +456.8 F
V/100: 104.9 cSt
V/212: 17.5 cSt
TOR: 522.0 F
VI: 184

10W30
P/P: -49.0 F
F/P: +453.2 F
V/100: 62.0 cSt
V/212: 10.0 cSt
TOR: 484.2 F
VI: 148

10W40 (MX4T)
P/P: -65.2 F
F/P: +487.4 F
V/100: 86.0 cSt
V/212: 13.8 cSt
TOR: 552.6 F
VI: 166

15W50
P/P: -49.0 F
F/P: +446.0 F
V/100: 125.0 cSt
V/212: 17.4 cSt
TOR: 495.0 F
VI: 153

20W50 (VTWIN)
P/P: -59.8 F
F/P: +518.0 F
V/100: 130.0 cSt
V/212: 17.7 cSt
TOR: 577.8 F
VI: 151

75W90
P/P: -50.8 F
F/P: +347.0 F
V/100: 106.0 cSt
V/212: 15.2 cSt
TOR: 397.8 F
VI: 151

75W140
P/P: -59.8 F
F/P: +429.8 F
V/100: 179.0 cSt
V/212: 25.3 cSt
TOR: 489.6 F
VI: 175

SYNTHETIC ATF
P/P: -65.2 F
F/P: +456.8 F
V/100: 34.0 cSt
V/212: 7.6 cSt
TOR: 522.0 F
VI: 203

JET OIL II
P/P: -74.2 F
F/P: +518.0 F
V/100: 27.6 cSt
V/212: 5.1 cSt
TOR: 592.2 F
VI: 113

JET OIL 254
P/P: -79.6 F
F/P: +489.0 F
V/100: 26.4 cSt
V/212: 5.3 cSt
TOR: 568.6 F
VI: 137

JET OIL 284
P/P: -70.6 F
F/P: +442.4 F
V/100: 17.6 cSt
V/212: 4.0 cSt
TOR: 513.0 F
VI: 128

MILITEC-1 (for comparison purposes only)
P/P: -45.0 F
F/P: +455.0 F
V/100: 43.41 cSt
V/212: 5.63 cSt
TOR: 500.0 F
VI: 63


Top 5 Criteria Compliant Grades:

1. 20W50 (VTWIN)
2. 10W40 (MX4T)
3. 5W50
4. 0W40
5. 0w30

Mobil 1 and Redline are both composed of synthesized PAO's and the nomenclature that the two companies use are just different ways of refering to PAO's (polyalphaolefins and polyol esters) both of which are esters formed from alkenes (also called alpha-olefins) which are compounds (possessing a double bonded carbon to carbon and no other functional group within the molecule) that are polymerized in order to form PAO's. The alkenes that are polymerized for use as lubricant basestocks are most commonly low molecular weight alkenes such as ethene and hexene.

Esters are simply a general class of chemical compounds and functional groups and are not indicative of lubricants only in that they also exist as flavor/scents, types of cleaning agents, plastics and plasticizers, personal care products like hand moisturizers etc, etc, etc.

The PAO's (PE, PAO, poly-ol esters, polyalpha olefins, what have you) that compose Mobil1 and Redline and Amsoil and any other brand names that I have missed are all the same thing as they all possess the same naturally high affinity for metal surfaces and tend to exhibit multigrade viscosity characteristics and do not require the addition of modifying agents to obtain these properties which is why they are so widely used in the lubricant industry.

Everything you ever wanted to know about the chemistry and properties of lubricating oils and greases:

http://www.bobistheoilguy.com

[krispos42]

1. Wow, that's good to know

What about Castrol Syntec? I have that stuff around because I use it in my car.


Now all I have to do it get it in a squeeze bottle! :-)

[benEzra]

2. Castrol Syntec would probably have similar properties to Mobil 1

for any given grade rating. Like M1, Syntec is a PAO-based full synthetic, not a blend.

If you dig around www.bobistheoilguy.com, you can undoubtedly find the specs on whatever variety of Syntec you currently use.

[SteveM]

3. Thanks for the tip. I'm paying more attention to my gun lubes...

I have been using for some time automotive wheel bearing grease for the hinge on my old Stevens 311D double-barrel .12 gauge; I mean, why use a thing oil on a door hinge? I do clean it out regularly in case grit gets in the area after a day of field use. I also use the same grease where my coil main spring strut fits into the hammer recess on my Ruger Police Service Six .357. Same reason: lots of friction, but no quick delicate actions. I think the action is smoother. I wonder if the Mobile will work well for the more "passive" works in my Ruger. I use Hoppes here because it isn't gummy and does cling. Same for pump shotguns and a lever action.

By the way, though it sounds counter intuitive, I freed up the bearings in a couple of old seized up floor fans with Rem Oil -- and they have been spinning merrily ever since. (I used to lube with used motor oil as there was some urban legend that lubricity for household use was superior when compared with fresh oil. But they got hot & stinky & seized up again.)

[benEzra]

4. The fans probably needed something with lower viscosity than motor oil...

fan bearings are very, very lightly loaded, and not much viscosity is needed to "float" them. A motor oil designed to float bearing surfaces under high loads was probably too thick for that application, given the low torque involved. Guns are more like engines in that regard, I think (high loads, large forces).

[JustABozoOnThisBus]

5. It's ok for semi-auto's with enclosed bolts

or for bolt-action. But for a semi-auto with an exposed bolt, like M1 Garand or M14 derivative, oil is annoying. It flies off the bolt or operating rod, and coats the safety glasses. So I use grease on those parts.

And the AR seems to work well, no matter the lubricant. I've used grease, oil, transmission fluid, I don't think it matters for the average target shooter. It might make a difference in a sandy/dusty environment.

[piedmont]

6. There might be one drawback...

According to the Wikipedia article on synthetic oils, the PAOs can cause or exacerbate stress cracking of some plastics, specifically Delrin. For most guns that's probably no problem at all. I don't know how common Delrin is for making firearms.

[benEzra]

7. I'm not familiar with any actual firearms using Delrin,

although Wikipedia says it is used in some paintball guns. If it's susceptible to PAO's, I'm not sure how well it would stand up to gun-cleaning solvents either.

[old mark]

8. benEzra, I have also been using Hi Temp

automotive grease to lube slides and wear points in auto pistols. Got a large tube at WalMart for about $3 several years ago, still have about 99% of it left. Works well as a rust inhibitor if you wipe it on then wipe it off the blue finish. It leaces a very thin film that keeps moisture out. Used it for years with great results.
FWIW,

Mark

[benEzra]

9. That makes a lot of sense as well.

Automotive greases are made for SEVERE duty...automotive wheel bearings probably see more action in a minute of driving as a firearm slide will see in a hundred years of shooting.

I had a tube of Outers Gun Grease years ago that would separate in the tube after only a couple of months, whereas I've never seen a tub of automotive grease separate at all.

The only thing about automotive grease you'd have to be careful of would be staining of clothes if you overdo it with some formulations, though that can be a problem with conventional gun greases as well.

[old mark]

10. I use it right out of the 2 pound tube,

apply it with Q-tips, rub most of it off. I use the purple High Temp variety. Never had any problems with it.
You don't need a lot, just apply it, wipe it off, leaving a very thin coatine you won't even see. Very slick, stays in position, inhibits rust, costs under $3 for a lifetime supply. Works very well on altu-loading rifles, shotguns, and any kind of lock or hinge that is used outdoors.

mark

[SteveM]

12. That outside coating sounds pretty good...

I think I'll follow your suggestion and use a little on the outside steel -- still blue and in good shape since 1955!

[Armadillo12]

11. I use Lubriplate

I wanted to add some info to this thread about using motor oil as a firearm lubricant. I see many people use it and also swear by it but there are many features of these oils that leave it far behind other choices.

Sure it will "work" and it is cheap to boot, but why go out and spend $500 to a thousand or more on your pistol or rifle and then cheap out on the one thing it needs to function properly.

Grant Cunningham's article "Lubrication 101" turned me on to Lubriplate as a firearm lubricant. He mentions motor oils...

Motor oils: Generally have good boundary lubrication (particularly the Havoline formulations), but very poor corrosion resistance and poor resistance to open-air oxidation. In addition, their pour-point additives often contain benzene compounds, which aren't a good thing to have next to your skin on a regular basis!"(AKA Toxic carcinogens). They also get thick at sub freezing temps.

Instead a twenty two dollar Magnum Lubri-Kit from www.lubrikit.com which is a 4oz bottle of Lubriplate FMO-AW oil and two 30cc syringes of Lubriplate SFL-0 grease will last you well over a year if using it, say once a week.

"If we were to spec out a "best in class" oil, it would be Lubriplate's FMO-AW oil, specifically the 350-AW weight. This is an oil designed with very high boundary protection and very high corrosion resistance - especially in the presence of acids, alkalis, and moisture. It is darned near tailor-made for our use!" - Cunningham

Lubriplate grease has been well known for many years to be a fantastic firearm lubricant.
Yes Grease is Good! If it turns oil it and if it slides grease it....

It was issued by the military for use on the M14 rifle (Civilian version is the M1A).
With tighter tolerances on newer weapons the SFL series, specifically SFL-0 is the best.

- Grant Cunningham writes "For such things as autoloader slides and rifle bolts,Lubriplate "SFL" NLGI #0 grease is my choice. In testing, it has proven itself superior as a general lubricant. It is white, aluminum-based, low odor, has superb boundary lubricants, and is designed specifically for use in environments that encounter a huge temperature range (-40F to 300F).
It's also resistant to water washout and acid/alkali environments, has great shear resistance, and doesn't oxidize like lithium greases will. As an all-around grease I've found nothing better." It is also nontoxic since it is used on food manufacturing machines.


Anyway those are my 2cents