Spring cleaning several of the scoped uppers (they get a little more attention in the bore than the full ones for the M16A1 - which are clean but maybe missing some of the rifling with age and a dozen cases of ammo  ;-) and again can not get over how much "black residue" (assume carbon but have not checked yet) comes out of a barrel that was "clean" using Hoppies or Shooters Choice (use new brush and patches with either until clean for three days in a row and then leave the Hopplies #9 wet in the barrel over night each day to remove a little more copper).

Using a clean brush, rod, bore guide and brushing with Kroil three sets of ten passes, the cleaning patch comes out black.  Repeat a couple times and then back to Hoppies or Shooters Choice to get the next layer of copper.  Using MPro 7 I get a similar but not quite as good result.

Being in aviation maintenance I have the opportunity to work with Kroil. I have experimented with it and used it as a bore cleaner and must admit that it does literally get your bore squeaky clean as far as carbon goes. But from my results it does nothing to remove copper deposits.

I would't recomend leaving Hoppes or Shooters Choice inthe bore over night.  The amonia in it will corrode the bore.  There is a local gunsmith and barrel maker that swears by Kroil as a cleaner.  He claims that it penetrates under the copper fouling and allows it to be swept out.  I beleive he coats the bore with Kroil and leaves it over night.  The Kroil has no amonia and will not corrode the steel of the barrel.

Hoppes #9 over night in a barrel will not hurt a thing.

ETA: I’ve recently switched to Break-Free Foaming Bore Cleaner and have had excellent results. So much that I am phasing out Hoppes #9.

I've soaked parts in hoppes No. 9 for months with no problems at all.  Hell I used to use hoppes no 9. as a rust prevent in the bore  Still watting on any form of pitting or etching to show.

Quoted: I've soaked parts in hoppes No. 9 for months with no problems at all.

I forgot about the little test I ran with Hoppes #9 and a bare aluminum section of cut carry handle.

After someone here claimed that washing out my rifles with a mixture of Hoppes and turpentine would corrode the aluminum receivers of my rifles, I dropped a section of cut carry handle into a container of pure Hoppes.



I forgot how long that piece sat submerged in the Hoppes but it was months. Maybe 6 months or more.



I pulled the piece out one day after having set the whole thing in the corner of my shop and completely forgot about it. Guess what? No damage at all to the exposed bare aluminum.

Don't leave Hoppes Elite Gun Cleaner in your bore unless you like rust.  

I use Kroil and patch until clean and dry.  Then I run JB on a patch and that seems to pick up any "loosened" residue.  I run patches after that until they're clean.  Then I run a lubed patch down the bore and put it to bed.

I tend to only leave the old classic Hoppies #9 in the bore over night.

Hoppes Elite Gun Cleaner, I have been told (and it looks similar) is the same as MPro 7 that I buy by the gallon for cleaning in the winter (no solvent fumes as is water based) and general bolt cleaning during the summer also.

The third Hoppies Bore cleaner I have used (for bolt guns) is their bench rest cleaner.  This can be used (per directions) to soak for a short period (hours not days) and has a higher ammonia content than classic Hoppies #9 but still a lot less than Sweets (?) or Barnes Bullets bore cleaners (which work well but have a much narrower window than the Hoppies bore cleaners).

When I am all done, tend to wipe the bore clean, run a few patches of classic Hoppies #9 through the bore as a solvent if using anything stronger and then the next day clean the bore again with #9 and dry.  At which point I run a few patches of Break Free CLP in the ARs  (chrome and stainless) just to have a oil film for storage (may not be required but does not hurt as long as you are not excess and/or remove before shooting).

Well back from da creek - time to unload the truck and then check the last two uppers and see if they are clean .......

 

Quoted: Don't leave Hoppes Elite Gun Cleaner in your bore unless you like rust.

That's because it's soap.

Quoted: Quoted: Don't leave Hoppes Elite Gun Cleaner in your bore unless you like rust.   That's because it's soap.

Tha'ts because it is water based.  The active chemical (soap) will dissolve any oil/protectant on the metal surface, which leaves the metal susceptible to rust from the water.  A short exposure is no problem.

Elite says do not leave for more than an hour.  I clean everything with it.  Then a Hoppes or Shooters Choice bore cleaner.  You can see the green on the patch with a couple of swipes.  Then Militec16 until the barrel feels warm.  Finally one pass of EEZOX.
But, I use Tetra products also and often Breakfree that my son brings home from Drill.
Hell I've got 10 different products and they all work.