Home Forums Hunting & Shooting Ask The Gunwriters Copper fouling in my 375h&h m70

Back in 89 or so my wife gave me a win mod 70 in 375h&h for Christmas. I’ve used it to take moose, caribou, elk, a mulie, a whitetail and even killed a few woodchucks with in to prep for some of this trips.

I may take it for moose in Newfoundland in ‘24 as a backup for my nephew.

The first rounds I ever loaded was back when were original Barnes X bullets. I could never get them to fly as well as the Nosler part 260’s I’ve shot ever since.

I STILL can’t get the smears of copper out of that dang thing from those x’s all those years ago!

Just spent more than an hour with some old Montana extreme, then wire brush then patches. You can still see the smears of copper at the muzzle.

I love the modern x’s I think they are awesome bullets. Those old ones sure left their mark!

A little copper wash affects nothing.

It can take a bit to remove but will come out, and then easily build up again. I rely on chemical removal - BoreTech Eliminator on many patches. My big bores copper foul badly.

I went through this with a .338 Win. Mag. I even had a friend put it on an Outers Foul Out. I worked forever breaking it in. After 5 shots it still fouls.

I may be wrong, but this is my best advice: Clean it really good one time. Then shoot it forever and don't worry about it. If it gets wet in the rain, clean and oil the the bore with a patch.

I've had good success with Sweets 7.62 copper solvant for removing all traces of copper prior to doing a Dyna-tek bore coat treatment. After Dyna-tek bore coat the few copper streaks that develop are inconsequential.

Wipe Out

Oh, don’t get me wrong, all those critters I’ve killed with it were AFTER the bore got “copper plated” courtesy of those old x’s.

Those 260’s still land right under the cross hairs at 200 and the point of the heavy duplex is my aim point for 300 and she’ll ring the gong every time.

I just irks me to see the copper gleaming up at me in the muzzle. I’ll get over it. (Maybe by killing a few whitetails in NC this fall and watching my nephew kill a moose with her next year!)

I’m really just venting.

Sweets is all I have used for many years.

The modern non-ammonia alternatives are just as good, and without the risk of etching the bore. I used to use Sweets for years too but switched a little while back.

There are three reasons to remove copper-fouling in rifle barrels:

1) It results in a significant difference in accuracy (larger groups). This can only be determined by totally eliminating copper fouling, then shooting comparative groups as more shots are fired without cleaning.

This may happen--but have also encountered quite a few barrels that grouped BETTER after more shots were fired. Have also encountered many that shot lousy after cleaning, but did far better after anywhere from 5-15 "fouling shots" fired.

2) If it results in bore corrosion due to moisture retention under the copper. This can be a problem in more humid climates.

3) It bugs you, due to being visible inside the muzzle. It may or may not occur further inside the bore.

You don't mention either of the first two. If the last one bugs you I would suggest Dyna-Bore Coat.

If you want far more details, I would suggest reading Chapter 10 in The Big Book of Gun Gack III, "Cleaning and Break-in of Barrels," available from www.riflesandrecipes.com.

I have never had an issue with Sweets so see no reason to change.

Fair enough, I never really had a problem with it either.

Thanks for all the tips and advice guys, I appreciate it.

Dyna Bore Coat changed my Sako 338 copper mine immediately! She’s a sweet little pussycat now and cleanup is a snap. One thing to remember: After the Bore Coat treatment do not use a brush to clean the rifle! Use something like Wipe Out so you don’t inadvertently remove the Bore Coat.

Copper fouling is a over rated issue. THat is until all the copper solvents started coming out of the woodwork and now we can't POSSIBLY live without them. I use Wipeout

If you want to get all the copper out and start from scratch, JB will do the job for you.

Once it's out, you'll be better able to evaluate any copper wash that gets laid down. You may find that it copper washes with the bullets you're now using and that's what you're really seeing.

Good shootin' -Al

Yep, if you're really peeved @ the streaks, JB, Iosso, or Flitz.

Could you include JB’s shipping address? I’m gonna send him several. Knew he “retired” & I’m looking forward to loading John up on fouled rifles...

Iosso is a bit more aggressive than JB, haven’t used Flitz. If using Iosso get one of their nylon brushes as it’s made to work with the bore cleaner and really breaks things up. After you get the copper out try using Lock Ease.
Been using it on a rifle that does foul, before last cleaning I looked at it with a Teslong and the fouling was there but pushed right out using wipe out accelerator and cleaner.
My only peave was that the Lock Ease left a stain in the bore where it never looked bright and shiny. Normal solvents CR10, Butch’s bore shine and Kroil wouldn’t remove it, solution was a little Lock Ease on a patch then push a clean patch through before the solvent dries. Presto bright shiny bore.

Use a powder with a copper eraser like CFE 223 or Stabal 6.5 or IMR 4166. It really helps.