extreme powder fouling becomes extreme copper fouling

A

AMMASHOOTA

Gary Gruber
I have been slowly working up a load for the my new .308. it has a Krieger barrel that stopped copper fouling after 18 rounds. I followed Krieger's recommended break in procedure.

i purposely started with minimum loads in the beginning to get comfortable with the rifle. i have been primarily a handgun shooter and this marks my first return to rifle shooting in over 3 years. the first 80 or so rounds had almost no copper fouling present, but quite a bit of powder fouling.

i think i can attribute that to the light loads.

now that i have my loads over 2600 fps, the carbon fouling has disappeared entirely but has been replaced by severe copper fouling. i am shooting 150g Sierra HPBT over about 45.5g of VV 150.

any ideas?
 
my opinion is that powder 'LIKES" to burn at some design pressure band. below that you get powder fouling/unburnt powder. once you get up in the band the powder burns and operates efficently.

as far as the copper fouling, who did the chamber ?

i believe the two are independent....

mike in co
 
mike in co said:
my opinion is that powder 'LIKES" to burn at some design pressure band. below that you get powder fouling/unburnt powder. once you get up in the band the powder burns and operates efficently.

as far as the copper fouling, who did the chamber ?

i believe the two are independent....

mike in co
Click to expand...

i did the chamber. PTG reamer. very accurate rifle.
 
Copper fouling

I see more copper fouling as velocity increases. - nhk
 
borrow a bore scope and look at the throat.....

how much over 2600....like 600 fps over ?? should be good to 2800 easy

mike in co
 
The idea that light loads are good, is pretty much false. The powder does not burn, and turns into an abrasive for the next shot. Completely burnt powder leaves a clean barrel with enough graphite precipitated from the burnt gas, to lubricate for the next round. If need be, go to a powder with higher graphite content for break in. Accurate, VV or Alliant.
 
If you read Krieger's explanation of what is taking place when you break in one of their barrels, it is all about smoothing out reamer marks in the throat, since the rest of the barrel has been lapped twice, once after reaming, a second time after rifling, hence Mike's suggestion. It is not so much about what reamer was used, but the way that it was used, and if every thing is lined up well, you can have a very accurate rifle with a copper fouling problem. Did the gunsmith use a system where the cutting fluid was fed under pressure, down the bore and past the reamer? I believe that it is the general consensus that this is the most fool proof method for producing a good chamber (including throat) finisih.

From their break in instructions:

Because the lay of the finish is in the direction of the bullet travel, very little is done to the bore during break-in, but the throat is another story. When your barrel is chambered, by necessity there are reamer marks left in the throat that are across the lands, i.e. across the direction of the bullet travel. In a new barrel they are very distinct; much like the teeth on a very fine file. When the bullet is forced into the throat, copper dust is removed from the jacket material and released into the gas which at this temperature and pressure is actually a plasma. The copper dust is vaporized in this plasma and is carried down the barrel. As the gas expands and cools, the copper comes out of suspension and is deposited in the bore. This makes it appear as if the source of the fouling is the bore when it is actually for the most part the new throat. If this copper is allowed to stay in the bore, and subsequent bullets and deposits are fired over it, copper which adheres well to itself, will build up quickly and may be difficult to remove later. So when we break in a barrel, our goal is to get the throat “polished” without allowing copper to build up in the bore. This is the reasoning for the "fire-one-shot-and-clean" procedure.
 
Boyd Allen said:
If you read Krieger's explanation of what is taking place when you break in one of their barrels, it is all about smoothing out reamer marks in the throat, since the rest of the barrel has been lapped twice, once after reaming, a second time after rifling, hence Mike's suggestion. It is not so much about what reamer was used, but the way that it was used, and if every thing is lined up well, you can have a very accurate rifle with a copper fouling problem. Did the gunsmith use a system where the cutting fluid was fed under pressure, down the bore and past the reamer? I believe that it is the general consensus that this is the most fool proof method for producing a good chamber (including throat) finisih.

From their break in instructions:

Because the lay of the finish is in the direction of the bullet travel, very little is done to the bore during break-in, but the throat is another story. When your barrel is chambered, by necessity there are reamer marks left in the throat that are across the lands, i.e. across the direction of the bullet travel. In a new barrel they are very distinct; much like the teeth on a very fine file. When the bullet is forced into the throat, copper dust is removed from the jacket material and released into the gas which at this temperature and pressure is actually a plasma. The copper dust is vaporized in this plasma and is carried down the barrel. As the gas expands and cools, the copper comes out of suspension and is deposited in the bore. This makes it appear as if the source of the fouling is the bore when it is actually for the most part the new throat. If this copper is allowed to stay in the bore, and subsequent bullets and deposits are fired over it, copper which adheres well to itself, will build up quickly and may be difficult to remove later. So when we break in a barrel, our goal is to get the throat “polished” without allowing copper to build up in the bore. This is the reasoning for the "fire-one-shot-and-clean" procedure.
Click to expand...

it's quite possible that my loads were too light during break in. i did do the one shot and clean for the first 18, at which point the copper was barely visible.

i think i will clean a bit more frequently for the next 20 or so shots and see if that makes a difference.

while i did not use a positive flush system to lubricate the reamer, i made very small incremental cuts, around .200 before extracting the reamer, flushing, etc. the finished chamber was quite clean and shiny and took only light polishing with some 400 grit. the final throat area was done in 20 thou passes for the last 100-150 thou.

i suspect that a borescope is the only way to know for sure what it looks like. hmmm, Christmas is coming up and my wife always asks me what i want and i usually tell her that i have everything i need. maybe i can change that story this year and see what happens.
 
Amma, question--after you clean your barrel completely do you run a patch of Kroil, WD-40 or some other light lube through the barrel before firing? ie a naked barrel vs a lightly lubed barrel.
Centerfire
 
Centerfire said:
Amma, question--after you clean your barrel completely do you run a patch of Kroil, WD-40 or some other light lube through the barrel before firing? ie a naked barrel vs a lightly lubed barrel.
Centerfire
Click to expand...

yes, my barrel is lightly lubed following cleaning.
 
It could very well be that you're not cleaning often enough. Benchrest shooters clean after every match with very few exceptions. Seldom will they shoot 20 rounds without cleaning. If, however, you're at war then more shots between cleaning is expected but try cleaning more often.

Here is an easy method to get rid of copper but most people get faint when they hear it. Run two wet patches through the bore then take a brush and wrap a few wisps of 0000 steel wool around the brush starting at the handle end of the brush and wrapping toward the tip. Load the brush and steel wool with J-B Bore Paste and make ten complete passes followed by two wet patches then two dry patches.

I promise you that in almost all cases the copper will be gone and it will NOT harm the bore. Lest you think that it will ask yourself how often have you cleaned case necks with steel wool and how many case necks have you ruined by doing it. Is brass harder than barrel steel?
 
MColeman said:
It could very well be that you're not cleaning often enough. Benchrest shooters clean after every match with very few exceptions. Seldom will they shoot 20 rounds without cleaning. If, however, you're at war then more shots between cleaning is expected but try cleaning more often.

Here is an easy method to get rid of copper but most people get faint when they hear it. Run two wet patches through the bore then take a brush and wrap a few wisps of 0000 steel wool around the brush starting at the handle end of the brush and wrapping toward the tip. Load the brush and steel wool with J-B Bore Paste and make ten complete passes followed by two wet patches then two dry patches.

I promise you that in almost all cases the copper will be gone and it will NOT harm the bore. Lest you think that it will ask yourself how often have you cleaned case necks with steel wool and how many case necks have you ruined by doing it. Is brass harder than barrel steel?
Click to expand...

i will give that a try. i clean every 20 rounds.
 
It's a trick that was shown to me by one of the largest custom barrel makers in the world. It works.

PS: Before I had my barrel flushing system I would never run the reamer in over .040-.050 before backing out and cleaning all chips and residue off the reamer. You should be especially careful about getting a chip under the reamer up near the shoulder and scoring the chamber wall. You can just about kiss that barrel ($300) goodbye.
 
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MColeman said:
It's a trick that was shown to me by one of the largest custom barrel makers in the world. It works.

PS: Before I had my barrel flushing system I would never run the reamer in over .040-.050 before backing out and cleaning all chips and residue off the reamer. You should be especially careful about getting a chip under the reamer up near the shoulder and scoring the chamber wall. You can just about kiss that barrel ($300) goodbye.
Click to expand...

Mickey,

I started off as a handgunner, way back in my youth. I shot a Model 29 with lead bullets because Elmer By-God Keith shot them in his 29's. And they leaded up my barrel sumpin' furious. The lead scoffed at my cleaning attempts with a brass brush. Then I found this steel wool type stuff that was marketed as a de-leader...don't even remember where I got it...but it was a WHOLE lot coarser than 0000 wool. Wrapped around a brass brush, that stuff worked like a charm. You could see the chunks of lead stuck to it when you pushed it out the barrel. Didn't seem to hurt the 29. Of course, I didn't have a borescope back then (now that I do, maybe I'll take a look). Then, of course, I read somewheres that doing that to a barrel was a mortal sin, and I had ruined my gun and was going straight to hell. So I quit doing it. Worked like a charm, though.

29's and BR guns...apples and oranges? Sure...but just my experiences.

As to chambering, on a pre-drilled/bored chamber, I'll go .100 until the shoulder propper starts cutting. Then it's .050 or less from there. Haven't ringed one yet.

Justin
 
Justin,
I have not had reason to use Mickey's method for a long time, but I have in the past, with 0000, and plenty of lubrication, and it worked as he reported.
Boyd
 
Zebra13 said:
Mickey,

I started off as a handgunner, way back in my youth. I shot a Model 29 with lead bullets because Elmer By-God Keith shot them in his 29's. And they leaded up my barrel sumpin' furious. The lead scoffed at my cleaning attempts with a brass brush. Then I found this steel wool type stuff that was marketed as a de-leader...don't even remember where I got it...but it was a WHOLE lot coarser than 0000 wool. Wrapped around a brass brush, that stuff worked like a charm. You could see the chunks of lead stuck to it when you pushed it out the barrel. Didn't seem to hurt the 29. Of course, I didn't have a borescope back then (now that I do, maybe I'll take a look). Then, of course, I read somewheres that doing that to a barrel was a mortal sin, and I had ruined my gun and was going straight to hell. So I quit doing it. Worked like a charm, though.

29's and BR guns...apples and oranges? Sure...but just my experiences.

As to chambering, on a pre-drilled/bored chamber, I'll go .100 until the shoulder propper starts cutting. Then it's .050 or less from there. Haven't ringed one yet.

Justin
Click to expand...

Justin,
I've scored two barrels in such a manner and, oddly enough, they were both .270 Winchester. I thought that I was being extremely careful but a chip still got under the reamer and they both scored just below the shoulder. If you examine a .270 case there is not enough taper in the case to let you run the reamer in a little deeper. It just won't clean up. I kept the barrels but nobody has wanted a .270 Weatherby yet and it's been over ten years. :(
 
MColeman said:
Justin,
I've scored two barrels in such a manner and, oddly enough, they were both .270 Winchester. I thought that I was being extremely careful but a chip still got under the reamer and they both scored just below the shoulder. If you examine a .270 case there is not enough taper in the case to let you run the reamer in a little deeper. It just won't clean up. I kept the barrels but nobody has wanted a .270 Weatherby yet and it's been over ten years. :(
Click to expand...

Mickey,

I hope you didn't think my reply was in disagreement with you in re: chambering. If so, that was not my intention. I agree with you on the .040 to .050 per if chambering without a flush system, when the reamer shoulder was fully engaged. On the pre-bore, with it bored out to just under shoulder diameter, not much of the reamer shoulder is cutting, so I would go .100. I didn't note any problems with chips...they moved down the flutes, didn't have to chip them out, etc.

On the .270's you mentioned, were the chambers pre-bored and was the reamer shoulder fully engaged? And do you think .100 is too deep on a pre-bore as noted above, i.e., prior to the shoulder fully engaging?

Your comments on the problems you've had with the .270's strikes close to home as I just finished a .270. The chamber checked out fine with a borescope...and I just may have got real lucky.

Justin
 
Justin, my post was simply anecdotal and not in response to yours. Not a problem at all, my friend.

I have never prebored a chamber and that would, no doubt, minimize the risk of getting a chip under the flute of a reamer. I use a barrel flushing system now and still only go in about .050 at a time but it's just habit, I suppose.

Have a great day and take care.
Warmest regards,
Mickey
 
MColeman said:
It could very well be that you're not cleaning often enough. Benchrest shooters clean after every match with very few exceptions. Seldom will they shoot 20 rounds without cleaning. If, however, you're at war then more shots between cleaning is expected but try cleaning more often.

Here is an easy method to get rid of copper but most people get faint when they hear it. Run two wet patches through the bore then take a brush and wrap a few wisps of 0000 steel wool around the brush starting at the handle end of the brush and wrapping toward the tip. Load the brush and steel wool with J-B Bore Paste and make ten complete passes followed by two wet patches then two dry patches.

I promise you that in almost all cases the copper will be gone and it will NOT harm the bore. Lest you think that it will ask yourself how often have you cleaned case necks with steel wool and how many case necks have you ruined by doing it. Is brass harder than barrel steel?
Click to expand...

here's a followup. i was out shooting yesterday and the ambient temp was ~60 degrees -- about 25 degrees less than when i first made this post. my load was 1.5g hotter than the previous load (around 2860 fps), and i am back to powder fouling -- almost no copper found during cleaning.

i guess i would have to attribute this to the temp variation. i shoot about 25 rounds and then clean. i'm going to bump the load up a bit (0.5g) and try again next week. no pressure signs at all.
 
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