Which motor oil for AR?

[jkasch]

Quote:
If cost is not a factor, then why are you not using a dedicated firearm lube? Sure - they are more costly per oz. But you just said cost does not matter.


I meant cost of a motor oil is not a factor. FireClean is $17 for 2oz. That's pretty expensive. But some guys like Cujet above, find that Mobil 1 works way better than Rem Oil.

I have a few dedicated gun oils but just wanted to know if I did decide to give motor oil a try, which one is best. After all, if it's equal or better, a lifetime supply is $8.00.

 

[Robenstein]

Originally Posted By: Al
Originally Posted By: Robenstein
Coolant is often cut with 50% water and many use the same basestocks as oil (group II, III, etc.)

Whats your point? My point is that ATF doesn't mix with water like motor oils do. Therefore therefore oil will penetrate the barrier that oil puts down on the firearm. I will admit that motor oil has corrosion inhibitors...so maybe that makes it suitable..I don't know.


my point is that ATF will emulsify with water...because 50% of the coolant in your car is water. I have seen it. Just like water in oil looks like chocolate milk, water and atf sort of look like pepto bismol.

 

[Al]

Originally Posted By: Robenstein
my point is that ATF will emulsify with water...because 50% of the coolant in your car is water. I have seen it. Just like water in oil looks like chocolate milk, water and atf sort of look like pepto bismol.

Again (as I said), mix ATF with water and you will see that it does not emulsify in water.

 

[Robenstein]

Agitate it and it will....just like motor oil. Let it sit and oil will float on water. I have seen it with racecars that only had water in the rad. Now if you are using a PAO based ATF it wont, but mineral oil bases will.

 

[dnewton3]

Originally Posted By: jkasch
Quote:
If cost is not a factor, then why are you not using a dedicated firearm lube? Sure - they are more costly per oz. But you just said cost does not matter.


I meant cost of a motor oil is not a factor. FireClean is $17 for 2oz. That's pretty expensive. But some guys like Cujet above, find that Mobil 1 works way better than Rem Oil.

I have a few dedicated gun oils but just wanted to know if I did decide to give motor oil a try, which one is best. After all, if it's equal or better, a lifetime supply is $8.00.


OK, I can accept your clarifcation.

I honestly don't think you're going to find any real difference in the syns.

But why not try a few on different guns and then report back! Let us know how it works, please.

 

[j4life]

i use a 50/50 mix of atf and 5w30 for my guns

 

[2cool]

I have found Rand CLP to be an excellent cleaner and lube; but only above freezing. It drops into the teens here at night, and the Rand won't "shake" in the bottle like my synthetic oils. If you're shooting an AR, I'd go with M1 0W-40 for all around all year use on the gas rings of the bolt. For any other use on a gun, you could consider Non-Detergent 30wt. engine oil available at many stores. Lubrication without the modern additive package.

 

[buck91]

I've asked similar questions, expect more geared towards use with my Glock and received rather unenthusiastic replies. To this day I've only ever used Break Free CLP with great results.

But on your topic, I'm not experienced with AR's but I have been using M1 20w50 motorcycle oil for osme general duties and it seems to work very well. Also have used M1 ATF and was very happy with the results. Lubricity-wise anyways.

Ya know, I didn't think about engine oil emulsifying water, though they usually do test low on corrosion tests. Makes me lean towards the M1 ATF as it may prevent corrosion better, its VERY slick, penetrates well and I suspect it should have pretty good thermal stablity- is it POA or...?

Anyways, I wouldn't doubt that any decent synthetic motor oil will lubricate for you well enough, if not excellent. What would draw my concern is the corrosion protection offered.

 

[Robenstein]

Most of the Mobil 1 auto products seem to be a mix of Group III synthetics which is just severely hydrocracked mineral oil and PAO basestocks. Mobil 1 used to be all PAO, but after the ruling that allowed Group III basestocks to be marketed as synthetic in the USA, many makers started reformulating products with Group III, Mobil included.

 

[lars11]

Right, the differencies in lubeability for different normal "weights" in this scenario is zero. And even if I suggest synthetic, dino will also do just fine.
And compared to an engine, there is no real wear that the oil should manage, say that you cycle 2000 rounds (a lot), compared to an engine that's only one minute run time.

You should have oil in there but the problem is really the dirt, not the exact oil viscosity or quality.

If you really are out hunting or shooting in like -35C, I would suggest running it completely dry och just a slight whiff of kerosene or wd40.

 

[dnewton3]

Allow me to mention this about using ATF as a rust preventative ...
It sucks.

I'll be specific and give you really good insight.

When I worked at the Ford Steering Systems plant in Indy (16 years) we did a LOT of precision machining on compoents for steering parts. Here, I'm going to specifically speak to the rack of "rack and pinion" units.

Once we ran these racks through the centerless grinders, we used a rust-preventative to store them before assembly. Generally this storage period would be anywhere from 1/2 hour to a few days. But occasionally, they would sit for a week or more due to production schedules, downtime, etc. Overall, that rust preventative would do a decent job.

At times, we'd run out of the rust preventative product (a liquid that was sprayed on with a typical hand-held garden sprayer). So some brilliant management person told folks to use the ATF we had by the bazillions of gallons. Being a steering systems production plant making both ball/nut and R&P steering systems, we used ATF by the rail-car load for testing and production fill.

Once the ATF was sprayed on the steering racks, it would only be about 24-48 hours (weather humidity dependent) until the racks started to rust. If you left ATF on a rack for more than a few days, not only would have have rust, you'd have a LOT of RUST! The ATF was very "thin" contrasted to the rust preventative used. The ATF would essentially roll off the rack and drip away, leaving a very thin film that was not capable of keeping the moisture from the steel. The ONLY way to get the ATF to work would be to re-oil the ATF onto the rack about every 12-18 hours. When they first tried this approach, they scrapped a LOT of racks after a long holiday weekend! ATF simply did not do what that moron thought it would, despite several of us warning him otherwise.

While ATF may not be bad in terms of lubricity; shooting a semi-auto with ATF would probably work. But using ATF as a rust preventative is NOT a good idea; there are far better products that can be used.

This is why I use gun oil for operation, and WD-40 for storage.

I do believe that a quality motor oil may be a good operational lube for a firearm, but when it comes to storage, you want something that will leave a barrier. Gun specific lubes do a great job at both. Or you can use motor oil for a lube, but then use WD-40 for storage.

My .02

 

[Al]

Originally Posted By: buck91

Ya know, I didn't think about engine oil emulsifying water, though they usually do test low on corrosion tests. Makes me lean towards the M1 ATF as it may prevent corrosion better, its VERY slick, penetrates well and I suspect it should have pretty good thermal stablity- is it POA or...?

Thats my thought. I won't argue with Robenstein any longer. Its useless. But for what its worth the "Conventional" AFT should perform equally well. Again it will NOT mix with water. Below is a shot of Advance Brand of ATF shaken vigorously and set over night.:

The interface is probably the resultof dispersants and not emulsifiers.
Acccording to Exxon/Mobil, https://www.exxonmobilchemical.com/Chem-...s_guide_en.aspx
ATF has a viscosity of cSt6.8. Additives are:
• rust inhibitor
• oxidation inhibitor
• corrosion passivator
• antiwear*
• extreme pressure friction modifier*
• dispersant polymer*
• defoamants
I use a 50/50 mix of ATF and Mobil 1 75W-90. The Mobil 1 also sheds water (like the ATF). That final mixture should give it a final viscosity of 11 (approx) or a 30 wt. oil.

I am sure the result would be a better lube than say FP-10. Not sure about the cleaning part of the CLP though. FP-10 is pretty thin so perhaps 75W-90 isn't necessary.

Probably silly to mix instead of using say FP-10, but its what I do and for AR's it might make sense.