Copper fouling on my new M70

[brushmore]

I understand that big bores tend to foul faster than the smaller calibers. However, I've noticed that my somewhat new Winchester M70 375 H&H seems to have some serious copper left behind every time I shoot it. If I look down the muzzle the lands look they are made of copper! After each session I've spent hours cleaning it with Remmington 40x. Every thing else doesn't seem to make a dent in the copper I've only shot it 3 times for about 40 rounds total, so I am still thinking it needs broken in still? The Hornady ammo was way worse than the Norma Oryx.

Does this sound normal for a 375 H&H? How much of the copper do I really need to get out anyway? Do I only need to worry about it once the accuracy suffers?

 

[BRICKBURN]

I personally worry about dirt/copper build up when accuracy declines.

Then wipe-out into the barrel and start over again.

I have noticed no difference in caliber with build up. I only use Barnes copper though.

 

[Royal27]

I personally worry about dirt/copper build up when accuracy declines.

This.

I also use Bore Tech for copper removal. Seems quicker to a clean patch than anything else I've ever tried.

 

[Buckdog]

Brushmore, that sounds like alot of copper fouling to me. Do you have a bore scope or access to one to take a look in the barrel? Factory barrels can be quite rough and will foul faster in general than a custom barrel which tend to be much smoother. Also I dont like hornady ammo as I feel it does put more copper off in the barrels. I have a bore scope so before everyone pounces on me defending hornady i promise you scope a bore after shooting hornady stuff and you will see what I mean. Noslers seem to be a harder copper jacket dont copper coat as quick. Swift A frames tend to lay down some copper too in the big bores. How have you broke in the barrel? there are lots of schools of thought on that but basically only shoot a few no more than 5 and clean for like first 50 rds. I think rem40x is an abrasive cleaner?? I wouldnt personally use an abrasive cleaner to remover copper as there are specific copper solvents and most are a ammonia base gel reacts with copper to dissolve it. comes out blue on a patch. will get the copper out much faster for you with less elbow grease. good luck to you PM me if you want specific chemicals I use, but you can look at the custom barrel makers site and everyone has there own recipe but most will use a specific copper solvent aka ammonia stuff instead of an abrasive.

 

[brushmore]

@Buckdog, I haven't broken in the barrel. I have shot maybe 10 rounds at a time in 3 sessions. Think it's too late? I have used Hoppes Bench rest but even after soaking overnight the patches are blue but still plenty of copper. I'll try a gel based one next time.

I'll look into getting a bore scope, can always use an excuse to buy a new toy!

 

[Royal27]

. I have a bore scope so before everyone pounces on me defending hornady i promise you scope a bore after shooting hornady stuff and you will see what I mean.

Doubt you'll get too many folks defending Hornady around here.

I hadn't heard the extra fouling of Hornady, but it certainly doesn't surprise me.

 

[Red Leg]

One other bit of heresy that I might offer expands on Brickburn's point. In most production rifles, a bit of build up is not a bad thing. Modern production barrels can be quite "rough", and a bit of fouling tends to mitigate that roughness for quite a few rounds. My experience is that many rifles tend to have a "sweet spot" of build up after three or four rounds which remains surprisingly constant for as many as a hundred rounds or so. Therefore, I never worry about completely scouring a barrel, even after accuracy issues - rather, clean it enough to get back to its particular accuracy window. My rifles receive a few whipes of ballistoil after use (a miracle product), and I don't worry until a really accuracy issue actually arises. Which on virtually all non-competition rifles, is virtually never.

 

[Ed Hawkins]

I have a M70 in 416 and is has show a tendency to copper foul quickly with Nosler Partitions. However, it hasn't affected the accuracy in the least. I have used a copper solvent to clean the barrel out, but three rounds later and it's fouled again. I've got a couple hundred rounds through my M70 now and the fouling remains fairly consistent as does the accuracy. Unless it's affecting the accuracy in your rifle, I wouldn't worry about it.

 

[Mekaniks]

Is it a blued regular barrel or stainless barrel?

I wonder if the metal composition of the barrel likes (is attracted to). copper for some reason more than normal?

I have a stainless barrel .338wm that I have fired 500 Barnes TSX. I always just pull a boresnake with a brush on it after shoooting. Then a couple months ago I used some Hoppes foaming bore cleaner on it. The first time it came out blue indicating copper. So I gave it a second treatment right away and it was clean.

If you have a local experienced gunsmith maybe have him take a look down it and give you a second opinion also?

 

[matt85]

Winchester doesn't have the best barrels... great rifles but they need to improve their barrels. I had a Winchester M70 in 7x57 and ended up having to return the rifle because it would foul up so fast that it was only good for a handful of shots before accuracy was gone. I tried everything including lapping the barrel and nothing fixed it.

my two current Winchester rifles are much better, a 416 RM and a 338 WM. these rifles don't seem to have a major copper fouling problem despite my regular use of Barnes bullets.

I recommend foaming copper solvents. ive had great luck with them when dealing with the fouling from Barnes bullets.

-matt

 

[Ray B]

According to a barrelmaker friend of mine- the worst bullets for copper fouling were those made from pure copper and the solid Barnes X bullets, before they reduced the friction by cutting rings in the body. At the time, the Cop-Out system of reverse plating the copper from the barrel with electricity was in vogue and he said that that system caused more damage than any amount of fouling.

 

[colorado]

The 570g A-Frames leave a lot less copper in my 500 Jeffery barrel than the 570g Barnes TSX's do. I've switched over to A-Frames for a couple of reasons, that being one of them.

 

[Gemsbok Gangsta]

Try using Wipe-Out sharpshooter.com
Combine with JB compound if needed.

 

[Shootist43]

Most copper removers leave a lot to be desired. However, there are two that work very well. KG -12 and Bore Tech Cu +2. Follow the instructions and it is almost like magic, the copper is gone without any damage to your barrel. I like the Bore Tech product because the used patches turn blue indicating the presence of copper. When the patches come out the same color as when they went in you are done. You will need to use a cleaning rod and jag that do not contain any copper.

 

[matt85]

im currently using:
https://www.midwayusa.com/product/272019/break-free-foaming-bore-cleaning-solvent-3-oz-aerosol
with this attachment (it fits):
https://www.midwayusa.com/product/237658/sharp-shoot-r-wipe-out-applicator-spout

I clean the barrel with Hoppes first then fill it with this foam and let it sit for a few hours. after waiting you just run a patch down the barrel (scrub it a little) and it will come out dark blue with little to no copper left in the barrel.

-matt

 

[sestoppelman]

Never heard that large bores copper foul quicker than small bores, I always figured it was more about velocity than anything else. I use Barnes CR-10 to get whatever copper that plain old Hoppes No.9 wont get out and it gets most of it, given time of course. I clean, with Hoppes and a brush, clean the crud out, wet down with 9 and let sit overnight and run a patch thru every day for a week, which works out because I shoot every week. But I get lots of green patches with old No.9.

 

[matt85]

Never heard that large bores copper foul quicker than small bores, I always figured it was more about velocity than anything else.

+1

-matt

 

[375 Ruger Fan]

This is the new barrel break end procedure I use. This came from a gun manufacturer. I now use Windex and my primary gun cleaner. It works and it's inexpensive. I've talked to many serious shooters and they have moved away from the petroleum based cleaners.

NEW RIFLE RECOMMENDED BREAK-IN PROCEDURE

For the first ten shots we recommend using jacketed bullets with a nitro powder load (Most Factory Ammo). Clean the oil out of the barrel before each shot using a simple window cleaner (like Windex®) which will soak the oil out of the pores. After firing each cartridge, use a good copper cleaner (one with ammonia) to remove the copper fouling from the barrel. We do not recommend anything with an abrasive in it since you are trying to seal the barrel, not keep it agitated.

After cleaning with bore cleaner, clean again with window cleaner after each shot. Use window cleaner because many bore cleaners use a petroleum base which you want to remove before firing the next shot. This will keep the carbon from building up in the barrel (oil left in the pores, when burned, turns to carbon).

To keep the temperature cool in the barrel, wait at least 5 minutes between break-in shots. The barrel must remain cool during the break-in procedure. If the barrel is allowed to heat up during the break-in, it will destroy the steel's ability to develop a home registration point, or memory. It will have a tendency to make the barrel "walk" when it heats up in the future. We have all seen barrels that, as they heat up, start to shoot high and then "walk" to the right. This was caused by improperly breaking in the barrel (generally by sitting at a bench rest and shooting 20 rounds in 5 minutes or so). If you take a little time in the beginning and do it right, you will be much more pleased with the barrel in the future.

Look into the end of the barrel after firing a shot, and you will see a light copper-colored wash in the barrel. Remove this before firing the next shot. Somewhere during the procedure, around shot 6 or 7, it will be obvious that the copper color is no longer appearing in the barrel. Continue the window cleaner and bore cleaner applications through shot 10.

Following the initial ten shots, you then may shoot 2 rounds, cleaning between each pair of shots, for the next 10 shots. This is simply insuring that the burnishing process has been completed. In theory, you are closing the pores of the barrel metal that have been opened and exposed through the cutting and hand lapping procedures.

 

[Grumulkin]

I tried Remington's bore cleaner once; it's terrible stuff. Hoppes also isn't that good. I'm also skeptical about using products where the recommendation is to not leave it in the barrel too long. I've gone to using Wipe Out and rarely use a brush. You can leave Wipe Out in a barrel as long as you like with no harm done and it works well.

Some barrels are rough and tend to foul more but it has nothing to do with bore size. For the most part, recommendations on barrel break in are nonsense. My current routine now with a new barrel is to be sure it's really clean and then apply Microlon Gun Juice. I sight in and shoot 10 to 20 shots and clean again to bare metal and apply Microlon again. I do this for the first 100 rounds or so. I did this with my last acquisition, a new Tikka in 308 Winchester, and that barrel even after 100 rounds down it has no demonstrable copper fouling.

By the way, a lot of barrels are hammer forged or button rifled and not cut; those processes leave an interior barrel finish that isn't going to be improved by lapping, etc.

 

[brushmore]

Thanks everyone for the feedback. So far the accuracy has been pretty good. So I won't worry about it but I am going to use a different solvent and get a bore scope.