AR reliability. Riddle me this.

[lysander]

i'd say the modern M4's and M16's would fare a lot better than the original ones that didnt have a chrome lined chamber or barrel... if you look at all the videos on youtube of people running their AR's for thousands of rounds without cleaning them or doing the bare essentials like wiping off the bolt or doing a quick clean of the chamber and barrel.. and then running it for another couple thousand rounds.. or the BCM filthy 14... now the only thing you cant recreate or simulate is the environment of Vietnam, with the humidity, rain, mud.. and having a M4 in that environment everyday...

First off - "The M16/AR-15 fails unless it is cleaned" is a myth, period.

The early M16 issued in Vietnam suffered reliability problems due to a number of problems, often blamed on the lack of cleaning tools, but that was just a convenient scapegoat.

1) Ammunition: Poor case hardness - because the specification for the .223 (later 5.56mm, M193) did not properly defined what it should be. Reports were that the case would stick in the chamber and could only be removed by knocking it out with a cleaning rod. When a case sticks like that in the chamber, it is not because it has a little dirt on it of the chamber is pitted, it is because the case has expanded during firing and not relaxed. Having a dirty or pitted chamber exacerbates this problem, but if a case relaxes properly after firing, normal extraction should be possible. Also, certain lots of ammunition loaded with WC846 would have fouling accumulate in the gas tube.

2) High cyclic rates: There are two causes for this - 1) Poor "Action Spring Guide" design, the original "buffer" used by Stoner was a very poor design which relies on a uniform amount of friction to work properly, Lubrication, or lack thereof, on the Edgewater-type spring changes the spring rate, and if enough dirt, or corrosion gets into the thing it ceases to be a spring and becomes just a solid block of aluminum. 2) Higher port pressure from all of the alternate propellants.

3) Intergranular exfoliation causing premature failure of the receivers.

[5.56 Bonded SP]

FYI motor oil works as a gun lube but its bad for your health. There's a reason mechanics wear rubber gloves when changing engine oil.

I can't imagine motor oil being any more unhealthy than clp, rem oil, or hoppes. I do feel like I am burning brain cells every time I use gun solvents, but that smell of hoppes does have a nostalgia to it.. Reminds me of cleaning my 22 with pops as a 10 year old

[AndyLate]

FYI motor oil works as a gun lube but its bad for your health. There's a reason mechanics wear rubber gloves when changing engine oil.

I'm not saying new motor oil is healthy, but the used oil the mechanics change is loaded with heavy metals and other toxins.

Andy

[5.56 Bonded SP]

I'm not saying new motor oil is healthy, but the used oil the mechanics change is loaded with heavy metals and other toxins.

Andy

I don't think any of us are using used motor oil.

I bought a new quart of synthetic motor oil for 5 bucks and it will last years for my guns. I don't see why people would want to use used motor oil when a quart of new motor oil costs a a couple bucks, less than a small fraction of what gun oil costs.


32 oz in a quart
quart of motor oil ~5$
Quart of gun oil ( 1 oz is usually ~ 5$ ) 5x32= 160$
So gun oil is roughly 32x as expensive as motor oil, yet motor oil has to meet industry highly regulated API standards, where as gun oil needs to meet no regulated standards.
Can't imagine why anyone would want to try and save money by using used motor oil smiley_freak.gif

[MegademiC]

Gasoline engine oils are carcinogenic when used. The polycyclic aromatic hydrocarbon concentration is higher in used gasoline engine oil. Diesel engine oil does not show the same rise in PAH, and the carcinogenic properties of used diesel are less defined.

I would t bet on used motor oil in an AR being safe, but it’s not defined as a known carcinogen at this time... at least from what I’ve seen.

They ChemE in me suspects the oils will break down and be carcinogenic, at least to a degree.

Edit- he was saying why mechanics wear gloves(I think). That said, the motor oil becomes “used” after the first shot, the question is what organics does motor oil used in a gun contain? It’s all acedemic. Wear gloves when cleaning a dirty gun- it’s cheap insurance and your wife/girlfriend will let you touch her more.

[5.56 Bonded SP]

I agree wearing rubber gloves is good. I do when I reload( make my own ) ammo too, but for other reasons.

Gun cleaning can cause lead exposure from what I understand, that is regardless of what lube you use.

[AndyLate]

I was indeed referring to mechanics wearing gloves due to the toxins (and now I know carcinogens) in used motor oil (as in used in a car). I use Mobil 1 in all my firearms. It's cheap and it works.

Andy

[Dr. Bullseye]

I was indeed referring to mechanics wearing gloves due to the toxins (and now I know carcinogens) in used motor oil (as in used in a car). I use Mobil 1 in all my firearms. It's cheap and it works.

Andy

I saw 15w-50 Mobil One in Walmart yesterday. Is this weight the hot ticket?

[AndyLate]

I saw 15w-50 Mobil One in Walmart yesterday. Is this weight the hot ticket?

I have been using Mobile One 15-50, but have no idea what the best viscosity would be.

Andy

[5.56 Bonded SP]

I saw 15w-50 Mobil One in Walmart yesterday. Is this weight the hot ticket?

I've used 0w20, 5w20, 10w30, and probably some other weights as well. They all worked just fine. Never had any problems. In fact, I find that motor oils keep my AR bolts wetter longer, leaving less hard carbon, and making them easier to clean after a few hundred rounds as well

Viscosity is probably area dependent but unless you live in the arctic circle it probably doesn't matter. Most motor oils are rated for below freezing weather, but that is where synthetic would shine... But unless you are operating on the north or south pole.. It probably wont matter.

Reference, it gets below freezing for months out of the year where I live.. never had a problem with my guns or my truck running 10w30 dino.