I am having trouble with my 6 creed. After 600 rounds on the barrel I am starting to get extremely dirty cases. Does anyone have an idea of what could cause this? It also is starting to show an ejector mark and heavy bolt lift. 40.2 gr h4350 2xf lapua brass annealed with my amp 108 Berger bt.
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Dirty brass in bolt gun
- Thread starter FatBatman
- Start date
Moisture or carbon ring. I had a carbon ring going that gave me some funky cases too. Was really tough to get gone too.
How did you clean it? If you got it clean every 100 rounds it isn't a carbon ring. Moisture, even a little can spike pressure a bunch though
I only ask because I thought I was cleaning well enough and I wasn't. I don't do Bronze brushes though so you might be doing better than I was at the time. You can see a carbon ring with a bore scope if you have one. Was there any moisture that could have gotten on your ammo or in your chamber?
That's what I had to do to get it. I have recently ordered some chamber plugs from possum hollow in hopes that I can plug my barrel from the chamber end and soak the chamber with boretech or clr (for 30-45min only) and not have to mess with pluging the muzzle end and all that goes with filling the chamber for a soak and plugging the muzzle end
Just some clr wet patches being allowed to sit and dampen it for 10 minutes should do to sufficiently loosen it to be wipe cleanable.
What are you using for case lube, and how are you removing it? Looks like you can see finger prints in the dirt.
I see similar marks on the brass when it’s been fired wet, (I.e. rain snow). What were the conditions when fired?
As a side note what action, barrel, and speed?
I see similar marks on the brass when it’s been fired wet, (I.e. rain snow). What were the conditions when fired?
As a side note what action, barrel, and speed?
Yes that will work if I keep it reasonably clean. It wouldn't work for the carbon ring that one time so I plugged the barrel with a foam earplug and let it soak for about 30 or 45 min and then scrubbed it with a nylon brush. That worked pretty well and got it. Now I do exactly what you're talking about in that area but I'm always sort of second guessing if the wet patch is sitting in the right place so I figured with the chamber plug, I can just drop a little down the barrel and let the chamber soak then clean as normal and it will just be easier. Also, it's a real PITA to plug the muzzle end of a barrel with a qd break on it.
Firing this thread back up. I am having the same issue.
6mmCM
Lapua Brass
40.1 4350
105 Berger HT
Dirty cases when I seated .010” Jump, but clean cases when I seated .080” jump.
Maybe the long seated bullets were in a carbon ring? I’m gonna clean it and see what happens!
6mmCM
Lapua Brass
40.1 4350
105 Berger HT
Dirty cases when I seated .010” Jump, but clean cases when I seated .080” jump.
Maybe the long seated bullets were in a carbon ring? I’m gonna clean it and see what happens!
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Do you use a bore guide when cleaning your barrel? Do you swab out your chamber after cleaning? I would think its a dirty chamber before anything else.
Yes and yes. Here is brass fired in the same sitting, but seated to .080 jump.
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I needed to seat my bullets deeper in the case for the problem to go away. My theory is the increased seating depth allowed a higher case pressure before the bullet leave the mouth. Allowing it to seal to the chamber.
I was thinking the same thing before, so I went from .002 to .004 neck tension. But It still happens. But it still makes sense, the deeper seated bullet has more “tension” just because there’s more surface area being engaged.
Was it a factory rifle or custom? I guess I should specify that it’s a custom rifle. I was skeptical about the chamber being too large.
It is a custom. I would also check your case base to shoulder on the clean vs dirty. My issue didn't show up intil 3 firings on the brass. I had my die set to bump the 1 xf brass that was actually giving me more bump than I wanted.
So when I sized this time, I backed my die off and used the method of incrementally sizing until the bolt closes with no effort. And that’s where I stopped. My brass is incredibly inconsistent in shoulder bump, to the point that most fired pieces didn’t even need any bump for the bolt to close.
You should definitely invest in a head space comparator. If fired brass doesn't need bumped to fit back in the rifle smoothly its likely not fully fireformed.
I have the regular ole Hornady comparator, but like I said, the numbers are often inconsistent that I decided to just use this method described above this time.
The brass has been fired 2 or 3 times now. And it’s Lapua brass. I’m considering selling it and trying another brand. I have 360 pieces that I have weight sorted and divided into 2 individual lots. So I have a lot of time invested in this brass and don’t want to start over haha.
Measure the clean brass and compare it to the dirty brass with the comparator just to see if there is a difference. Bump inconsistency could also be a cause lube issue.
That's definitely not going to be a thing. Also, the shoulder does most of the sealing. Unless your chamber is quite a bit larger than the case, a little more bearing surface in the neck isn't going to be enough matter.
Case in point, virgin brass shoulders move .005 or more the first firing and there's no issues unless something is wrong in the chamber. First time firings fit the "loosest" in chamber and would see more issues than fired brass bumped a littler further back as virgin brass would take the most increase in size to seal a chamber.
You could check this theory by loading the bullet into the lands. As that will assure that pressure goes up.
Did you remove the firing pin assembly as well as the ejector? If not, you're going to have shoulders bumped a little too far back because of the ejector.
If the bolt is stripped and you sized down until bolt falls free with gravity, then you're fine. Comparator won't change much. But it will assure you that you're bing consistent with your sizing.
So I just measured 2 dirty cases and got 1.5535 and 1.5525. The 2 clean cases measured 1.556 and 1.5575. See picture, the longest or most expanded cases sealed at the neck. The second longest sealed at the shoulder and the other 2 didn’t seal. Both on the left were seated to .010 jump and the ones on the right were seated .080 jump I’m pretty sure.
All cases fired 2 days ago and were annealed with AMP and sized with the same Hornady die in the same session. Lubed with Hornady one shot.
I will say I use a .267 neck bushing with a .240 expander ball. I don’t like the idea of the expander ball on the up stroke, bc in my head I feels like it pulls the shoulder back up a little bit.
I will be swapping to a mandrel soon.
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Yes I removed extractor, but left the firing pin, but the brass was deprimed so the firing pin wasn’t touching anything. The firing pin was needed to retain a pin that held the bolt head in.
You have 3-5 thou more growth in the sealed cases so that means the case hasn't sealed in the chamber on the dirty brass. Take those 2 cases load them to .080 off fire and measure them. If they grow to .557. What coal are you loading to? I had to go shorter than what berger says to get it to seal up properly.
The dirty ones measure .108” of bullet shank into the neck, while the clean would be .178”
Okay I will do that as soon as I get some time. My lands measured 2.271 and I loaded CBTO 2.261. I don’t measure COAL.
Just FYI, if you're not already aware: The best way for another shooter to now how you're particular cartridge set up relates to their gun is to communicate what your COAL is (an average, of course). Because different chambers are of different lengths, CBTO doesn't say anything about the cartridge dimensions and how it might related to other chambers.
So I just measured the shoulder on some I had loaded to .010 Jump that I can see stains on from previous gas leaks on the last firing(the problem loads). It measured 1.5565 before firing and ¿SHRANK? to 1.5555 after! What the heck. So I grabbed another and seated it deeper and it GREW!
First 2 pictures over the bench are of the brass that shrank after firing and second 2 over the rifle are of the brass that grew.
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I assume that is the length of it loaded to .010 off. You may just need to seat the bullet deeper to resolve this issue like I did.
Have you verified that your calipers are reading correctly? I've had both a high end and a cheap digital over the years and both read incorrectly. I now only use a dial caliper.
Most people can't use measuring tools to save their life and even more think becuase it spits out a number( here is a hint.. calipers are not accurate to the 4th decimal place and most aren't repeatable to the 3rd). I always get a chuckle out of these threads when people rattle off these exact numbers and think they are reality.
Machinists spend 6 months In their first year learning how to use measuring devices and their limitations. If you did not get taught propperly by someone who knows what they are doing there is a high probability you are doing it wrong.
Hard to be a proficient reloader when you don't even know what your looking at.
Machinists spend 6 months In their first year learning how to use measuring devices and their limitations. If you did not get taught propperly by someone who knows what they are doing there is a high probability you are doing it wrong.
Hard to be a proficient reloader when you don't even know what your looking at.
Thanks for hopping in and talking trash we find It very helpful!
Yes calipers are reading correctly.
And while I am no means a machinist, I don’t think those skills are necessary when reloading to a certain extent. I can measure the same piece of bass 10 times and get the same exact number. That tells me the calipers are consistent. The number it reads is irrelevant in this situation. What matters is the different reading from one to another.
You don’t have to be a machinist to reload ammo. lol
If the necks of the cartridges loaded long have not expanded on firing, I had a similar problem when using Berger Hybrids in a relatively long freebore chamber. At 0.020" jump the precision was iffy and I could not drop a bullet down the neck of a fired case. Had to seat them 0.120" from the lands before the precision improved and the necks expanded on firing.
Just like FatBatman, I suspect that the chamber pressure does not get high enough to fully expand the case by the time the bullet shank leaves the neck. This then allows combution gasses escaping behind the bullet to fill the space around the case.
If I was in your position, I'd seat the bullets deeper. You'll probably find that your presicion will increase too. As some YouTube personality once said, chasing the lands is stupid.
Just like FatBatman, I suspect that the chamber pressure does not get high enough to fully expand the case by the time the bullet shank leaves the neck. This then allows combution gasses escaping behind the bullet to fill the space around the case.
If I was in your position, I'd seat the bullets deeper. You'll probably find that your presicion will increase too. As some YouTube personality once said, chasing the lands is stupid.
Okay I will try that! I don’t really chase the lands, i was just trying that depth to see what happens! I already know that seating deeper fixes the issue, so I’ll just do some development there.
Could there be an issue with the chamber or how it was chambered? (Now that’s a question for a machinist.)
My gunsmith is a machinist by trade. I know there are a lot of people out there that buy a lathe and call themselves smiths, but this guy is a machinist and I’ve always heard him to be good.
Consistancy and accuracy are different. Do you have gauge blocks to verify your caliper?
I've heard of wide chambers shortening brass but have never witnessed it personally.
You can get headspace gauges and check for yourself if you want. I assume your Smith would of checked that before handing it off to you. If the only problem you have is the brass not sealing and seating deeper fixes it likely your barrel is fine.
No, but I have a piece of brass that I measured and recorded the length, and I null it to that every time before I measure. I don’t care if the reading if the reading is accurate, I just care about consistency
Brass needs to be blown out to fill that chamber or it will never seal . You can jam a few hard with a semi-stout load , instead of building pressure in the brass and losing a lot of that with the long jump .
Good news update! Thanks to everyone for the help in guiding me in the right direction!
I loaded 3 each with .080, .100 and .120” jump, no dirty brass, and each fired case measures ~ +.002 larger.
The rounds loaded to .080 jump sealed around the shoulder and the other sealed around the neck. So I guess my rifle just has a little too much free bore.
Here are the 3 groups shot @250 yards.
Thanks again for the help!
I loaded 3 each with .080, .100 and .120” jump, no dirty brass, and each fired case measures ~ +.002 larger.
The rounds loaded to .080 jump sealed around the shoulder and the other sealed around the neck. So I guess my rifle just has a little too much free bore.
Here are the 3 groups shot @250 yards.
Thanks again for the help!
