Too clean or not clean enough? (copper fouling)

Welcome to the forum.

A barrel can't be too clean. From the get go, every time you send a bullet down the barrel it leaves a layer of copper followed by a layer of carbon. The microscopic pores in the barrel fill in, the valleys left from the machining slowly get filled in and the hills get their tops knocked off with every shot.

I alternate copper and carbon cleaner. I found out that if I use a bronze brush, or a brass/bronze jag with the copper solvent on the patch that the jag will leave copper residue on the patch and I think it's in the barrel. I have switched to using nylon brushes and nickel plated jags to eliminate that problem. If the brush has black bristles, sometimes they will leave some black in the barrel.

Black residue on the patch is carbon, blue is copper.

I gave my nephew a Mossberg .270 rifle NIB. During the break in procedure, we went from having to pound the cleaning rod/jag/patch down the barrel to using 2 fingers to push it down (from starting to break in to finishing breaking in the barrel).

I will use an aerosol product called Wipe Out but before I use it I give the barrel a swab with the accelerator. If I don't use the Wipe Out, I use Montana Extreme Copper Killer for the copper and Hoppes Elite Carbon, Lead and Copper Remover (which I think they don't make any more). I don't use the Hoppes Elite for lead or copper, just for carbon, the Montana Extreme is much better for removing copper.

When breaking in my nephews gun, we shot 40 bullets and went through at least 300, if not 400+ patches.

The patches have to come out clean. Once the barrel is clean, then you can figure out just how dirty the barrel likes to be to shoot good. Yes, it is a PITA, but that's the only way to find out what the gun likes. Some like a squeaky clean barrel. Others won't keep good accuracy until they have 5-10 shots down the tube, then stay accurate for 30-40 or more shots.

I run a wet patch down the tube, wait a few minutes then run a dry patch. Keep repeating the process until the dry patch after the wet one is clean.

After Montana Copper Killer, and the Wipe-Out, I like Shooters Choice Copper Remover.

I have a 30-06 that I haven't shot for a VERY long time. Think late 1980's..... I only used Hoppes #9 to clean it back then, and one of these days I will put the copper cleaner to it. I expect to see indigo blue patches.

I was wrong. Actually Have Mcmillan

From: Gale McMillan <" gale"@mcmfamily.com>
Newsgroups: rec.guns
Subject: Re: Barrel break-in necessary?
Date: 7 Jan 1997 20:40:25 -0500

Mike Sumner wrote:
> ...

As a barrel maker I have looked in thousands of new and used barrels
with a bore scope and I will tell you that if every one followed the
prescribed break in method A very large number would do more harm than
help. The reason you hear of the help in accuracy is because if you
chamber barrel with a reamer that has a dull throater instead of cutting
clean sharp rifling it smears a burr up on the down wind side of the
rifling. It takes from 1 to 2 hundred rounds to burn this bur out and
the rifle to settle down and shoot its best. Any one who chambers rifle
barrels has tolerances on how dull to let the reamer get and factories
let them go longer than any competent smithe would. Another tidbit to
consider, Take a 300Win Mag. that has a life expectancy of 1000 rounds.
Use 10% of it up with your break in procedure for ever 10 barrels the
barrel maker makes he has to make one more just to take care of the
break in. no wonder barrel makers like to see this. Now when you flame
me on this please include what you think is happening to the inside of
your barrel during the break in that is helping you.

Gale McMillan
NBSRA IBS,FCSA and NRA Life Member

From: Gale McMillan <mcmillan@getnet.com>
Newsgroups: rec.guns
Subject: Re: Good barrels for Rem 700 in .308?
Date: 10 Feb 1996 12:50:53 -0500

Consider this, every round shot in breaking in a barrel is one round off
the life of said rifle barrel. No one has ever told me the physical
reason of what happens during break in firing. In other words to the
number of pounds of powder shot at any given pressure, is the life of the
barrel. No one has ever explained what is being accomplished by
shooting and cleaning in any prescribed method. Start your barrel off
with 5 rounds and clean it thoroughly and do it again. Nev Maden a
friend down under that my brother taught to make barrels was the one who
come up with the break in method. He may think he has come upon
something, or he has come up with another way to sell barrels. I feel
that the first shot out of a barrel is its best and every one after that
deteriorates until the barrel is gone. If some one can explain what
physically takes place during break in to modify the barrel then I may
change my mind. As the physical properties of a barrel doesn't change
because of the break in procedures it means it's all hog wash. I am open
to any suggestions that can be documented otherwise if it is just
someone's opinion forget it.

Gale McMillan
From: Gale McMillan <" gale"@mcmfamily.com>
Newsgroups: rec.guns
Subject: Re: Remington 700 break in
Date: 8 Aug 1997 00:01:07 -0400

Arthur Sprague wrote:

# On 29 Jul 1997 22:50:26 -0400, whit@cs.utexas.edu (John W. Engel)
# wrote:
#
# #This is how (some) benchrester break in barrels, and it does work.
# #The mechanism is that the bore has pores in it (microns in size).
# #If you simply shoot a box or two through it without cleaning, the
# #pores fill up with gilding metal, and stay that way. If you
# #follow the above procedure (and they mean *clean* between shots!),
# #the pores are "smoothed over" with each successive shot. A barrel
# #correctly broken in is MUCH easier to clean than one that is
# #not. If it is a good quality tube, it will also be more accurate.
# #Regards,
# #whit
#
# Well, the range hours here are quite limited. On my first trip I
# managed to fire a whole fourteen rounds, with a thorough cleaning
# after each round. It couldn't hurt! Fun gun! Difficult to think of
# .223 as a battle round after experience with .30-06 and .45ACP, but it
# surely going to be a pleasure to shoot.
# Thanks to all for their advice.

This is total hogwash! It all got started when a barrel maker that I
know started putting break in instructions in the box with each barrel
he shipped a few years ago. I asked him how he figured it would help
and his reply was If they shoot 100 rounds breaking in this barrel
that's total life is 3000 rounds and I make 1000 barrels a year just
figure how many more barrels I will get to make. He had a point it
defiantly will shorten the barrel life. I have been a barrel maker a
fair amount of time and my barrels have set and reset bench rest world
records so many times I quit keeping track (at one time they held 7 at
one time) along with HighPower,Silloett,smallbore national and world
records and my instructions were to clean as often as posable preferably
every 10 rounds. I inspect every barrel taken off and every new barrel
before it is shipped with a bore scope and I will tell you all that I
see far more barrels ruined by cleaning rods than I see worn out from
normal wear and tear.I am even reading about people recommending
breaking in pistols. As if it will help their shooting ability or the
guns.
Gale Mc.

Tend to agree. I'd check scope, mount and base as a starting point

I went through this with my long range rifle. Scope base loosened up....

Check scope base, scope rings to base and make sure scope didnt' move in the rings. Check torque values of the action to stock screws too.

If it was an abrupt change then it's something mechanical. If it was a gradual change, I'd look at the barrel.

Using factory ammo, switching ammo could do it too. Dinging the crown of the barrel could do it too.

Lots of things to work out, I hope the OP gets back to us and tells us what he has checked and what he found.

Shooting for too long of a time and getting the barrel really hot will change group size too.

As for Gale McMillan saying that breaking in the barrel isn't necessary, I agree with him on custom hand lapped barrels. BUT for a factory gun? It should be done. How many here have a custom aftermarket barrel on their guns? I'll bet it's less than 10 members.

Thanks to everyone for your feedback. I had my first chance to get to the range today after giving my barrel a thorough cleaning (>100 pads and alternating between regular and copper solvents which was much more effective..something I hadn't considered until esshup said that's what he did). I shot 4 groups of 5. The first 2 groups weren't looking any better than before (3.5"). However, the last 2 tightened up considerably (1.5") so it looks like this might have been the culprit and that my barrel requires about 10 fouling shots before it's optimal (good to know).

It makes sense though that it would more likely be a mechanical issue since it was a sudden change. I did previously index scope/rings with a fine-point silver sharpie. Unfortunately though, the lines have smudged enough that I can't tell whether they've shifted. I lent my torque screwdriver out but will recheck tomorrow when I get it back (and maybe look for something less likely to smudge to mark it again).

Now however, I'm not sure if I should clean out barrel again and if so...to same degree? There seem to be 2 schools of thought - one says not to clean until accuracy starts to diminish and the other says to clean after every shooting session regardless (or maybe these are just the extremes and there's an ideal middle-ground). On the one hand, I see the wisdom of "if its not broke, don't fix it" but on the other hand, I'm not anxious to make 100+ pad cleaning sessions (which took all night) a regular thing even if only every 2 months.

Well, first thing's first...I should confirm that scope isn't loose (just didn't want to delay providing feedback).

Other info:
- I'm using same ammo. Initially, I've tried as much of a variety that I can get my hands on, which isn't much these days, but I have been using the same high quality cartridge before and after accuracy drop.
- Barrel heat might be a factor. With last bad session, I wasn't monitoring it and did notice that it was quite warm after I was packing up to leave. With this most recent session though I was careful to allow it to cool between shots.

If there's one thing that I can say with 100% confidence it is that there are A LOT of variables involved with good marksmanship (more than I initially realized as a beginner). As mentioned before, my ultimate goal is to hunt deer with this rifle so I just want to make sure that both I and my rifle are capable of reliably making an accurate and ethical shot.

^^^ What he said.

Unless you are going to let it sit for a long time I would leave it dirty until the accuracy starts to degrade.

If you are buying factory ammo, take a look on the box for a lot number. Different lots will also shoot differently too. Even us guys that reload, if we switch lots of powder, use different brass, and sometimes even if we just switch primers, the groups won't be the same.

I will shoot my guns before deer season, and not clean them until season is over, and that will be multiple months.

Barrel heat will be a factor. With a few of my rifles, 3 shots is about the most that I can shoot in a row without letting the gun cool down. If you cannot hold your hand on the barrel comfortably for 15-20 seconds right in front of the chamber or right in front of the scope, the barrel is too hot. Shooting a hot barrel will wear out the barrel faster i.e. erode the throat faster. That will cause your accuracy to change too.

After opting not to clean barrel since last session (a week ago) and re-checking scope mounts to ensure that they hadn’t loosened (they hadn’t), I went to range again and had tightest groups yet.

So, I’m pretty sure now that it *was* the thorough (but improper) cleaning that was the cause of my initial accuracy problems.

With a squeaky clean barrel, its accuracy is within 3.5 inches. After about 15 shots, it shrinks to about 1.5. And after another 5-10 shots, it shrinks to sub-MOA.

Aside from learning this important piece of info, the other valuable thing I’ve learned is that it’s necessary to alternate between cleaning carbon and copper which must be collecting in concentric layers.

Otherwise, if I try cleaning all of the carbon first followed by copper, it must be leaving an uneven surface in barrel resulting in a dramatic drop in accuracy (at least that’s my best theory).

So, when accuracy begins to drop again, I’ll either need to scrub it back to bare metal (another 100+ session of alternating carbon-copper patches) then not expect sub-MOA for 20 shots OR I might be able to do a partial (but still alternating) cleaning with hope that I can regain accuracy but without need for 20 fouling shots.

Thanks all for your help.

Here are last 2 groups I shot. First 3 (upper left) are 0.542 MOA. Last 2 (after slightly adjusting scope windage and elevation) are 0.338 MOA! Seize-fire called out before I could manage a 3rd but I’m still happy with results!

imgur.com/a/zlsPmLx