In one of the ranges I frequent, we primarily use diesel as our cleaning solvent. It is very very effective. My question is, can regular use of diesel potentially cause damage to our firearms?
No. [obligatory extra characters to keep the software happy]
Diesel works OK, as well as automatic transmission fluid for cleaning.
Clean, new motor oil works as a satisfactory lube.
several years back my unit was down in honduras training the honduran marines and they used motor oil to clean their weapons. I was shocked, and couldnt possibly see how it could work sufficiently but it did. It seemed to do the job, i am just not that brave. I use dilluted simple green to clean my weapons, and then oil it up afterwards.
But it could cause damage to your skin. If you are going to use diesel, wear rubber gloves.
Good point… It definitely is some pretty nasty stuff.
Standard off the shelf Simple Green is bad for aluminum. There is a special aircraft version that is OK. There are better cleaners for guns.
100% synthetic motor oil is a good solvent for most gun fouling. Some of the new chelation cleaners like Bore Tech Eliminator seem to do a pretty good job even on copper without harming the parts.
To answer the OP’s question - diesel will work well as a solvent but there are additives in the fuel that are not very friendly to people. It shouldn’t harm the guns. It will remove all the oil.
I have used Simple Green mixed with HOT water for cleaning a variety of weapons and had no issues. That includes aluminum parts (rails) as well. We used a compressor to displace any moisture and made sure everything was dried afterwards.
I use WD40 and kerosene. I spray the bore/chamber, BCG, and upper receiver with WD40. Let it sit a bit and clean with the usual tools. I then “rinse” with kerosene, wipe off what I can, let dry and lube.
I also occasionally de-grease the BCG with alcohol before lubricating.
I use Hoppes #9 and brake cleaner, with Mobil1 to lube. I am going to change that though and try out a mixture/method by member name QUIB over on TOS. He uses Odorless Mineral Spirits and BreakFree CLP mix to clean parts in a bath / soak method. I may even try a batch of Ed’s Red (minus the acetone) for cleaning if I don’t like the OMS/CLP potion.
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Ed’s Red is mostly all I use on rifles.
1/3 Acetone
1/3 ATF Dextron 3
1/3 Kerosene. The true Ed’s Red formula had Lanolin and more in it, but I’ve found those 3 mixed together do a WONDERFUL job. Just keep it off Plastic unless you like the Salvidor Dali look.
All my handguns get stripped and dropped into my Ultrasonic cleaner.
The version of Ed’s Red that I use is equal parts of kerosene, Dexron ATF, Acetone and mineral spirits. I mix up a quart at a time and store it in a mason jar. I pour a small amount into a smaller jam jar for cleaning.
In my opinion it does a better job of cutting carbon than anything else. I soak the tail end of the bolt while I clean the rest of the rifle and the carbon mostly whipes right off with a rag.
Ed’s Red has an unpleasant smell so in the winter when I have to clean indoors I switch to Hoppes.
I bet the wives love the smell of that diesel fuel in the family room.
Save yourselves a lot of trouble and get some Slip 2000 carbon killer.
Iraqgunz:
A few years ago I spoke with the chemist at Simple Green to see if it was OK for aluminum. The info I am relating here is what she said.
Simple Green had to change their formulation and offer it in an “aircraft” version to be certified for use on aluminum aircraft parts. A quick cleaning may be OK. The problem comes if it gets into any cracks or crevices or under fastener heads etc and doesn’t get rinsed out completely. Over time it will remove anodizing and corrode the aluminum.
How’s that OMS/CLP working out? Give it a try yet?
to the OP,
I use it regularly and never had a single problem in many years.
of course I use “real” gun cleaning solvent as well.
I still like Kleenbore #10 as a cleaner - also does WONDERS for taking duct tape residue off mags that have been in the sandboxes (I like to pick those up on the cheap at gun shows, clean 'em up, add a Magpul follower, and then have a nice range mag for the effort!). I then use Slick50 Lube to oil 'em - rifle and mags. 
It works, but I’d be concerned with working with it long term, health wise. As someone else mentioned, I saw the hondurans cleaning with motor oil and other folks using diesel. I use WD-40 to hose down and clean the upper and lower. After your done, it’s already lubed. Just lube the BCG with a more durable lube(what ever your favorite is) and your GTG.
Speaking of lube, I’ve been experimenting with a couple of motor oils, 10W Mobil 1/Militec 1 and 20W Royal Purple(being completely synthetic)/Militec 1 (2/3,1/3 mix). The royal purple mix is as thick and durable as Slip EWL.
Better than gas but still contains Benzene which is a proven carcenogen. Think of your liver.
Wear good thick butyl gloves if you insist on using it. Disposable rubber gloves don’t cut it.
Brake cleaner-non chlorine seems to work well for me.