Excessive carbon on 7mm case? Update.
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Brass was clean,chamber was fouled up,but not with oul.
Powder was purchased last month from higgenson.
And this is the first time happening.
The brass started at 2.495 and ended at 2.470, after 6 firings,Fl sized.
Powder was purchased last month from higgenson.
And this is the first time happening.
The brass started at 2.495 and ended at 2.470, after 6 firings,Fl sized.
When you FL size, how much are you bumping the shoulder back? What do you set your neck tension at? Sorry for the questions, I have never seen a case that dirty, even my 9mm are less dirty buy a long shot. Also your brass is short before sizing, and after firing? ever needs trimming? What is your neck tension? .284 bullets used?
Ditch the brass and try different stuff.
Ditch the brass and try different stuff.
Your chronograph numbers will give you a good indication of how the load is performing.
You said it doesn't feel very "stout", and it's not acting that way either from a sealing point of view.
If your chronograph numbers are quite low, adding more powder is not the answer.
Vihtavuori's suggestion for N 160 with the 140 gr A-Frame tops out at 62.2 gr of powder. You're already nearly 4 grains over that.
A little bit of variation between bullets of similar construction isn't unusual, depending on the individual bullets' bearing surface.
Having said that, if you get low velocity and carbon tracking on the case at 4 gr over recommended max load, there's something wrong, regardless of the bullet you're using.
I'm assuming you've weighed and measured the bullets to be sure they're as advertised?
If yes, it might be a bad container of powder. That'd be very unusual, but not impossible.
You're using the right primers? I'm guessing they should be large rifle magnum primers? Any chance they're not? Cold weather and weak primers wouldn't help the situation.
You may simply have a situation that can't be easily resolved. My 243 load using IMR4831 was like that. It went from fine to filthy with not much, if any, in between.
You said it doesn't feel very "stout", and it's not acting that way either from a sealing point of view.
If your chronograph numbers are quite low, adding more powder is not the answer.
Vihtavuori's suggestion for N 160 with the 140 gr A-Frame tops out at 62.2 gr of powder. You're already nearly 4 grains over that.
A little bit of variation between bullets of similar construction isn't unusual, depending on the individual bullets' bearing surface.
Having said that, if you get low velocity and carbon tracking on the case at 4 gr over recommended max load, there's something wrong, regardless of the bullet you're using.
I'm assuming you've weighed and measured the bullets to be sure they're as advertised?
If yes, it might be a bad container of powder. That'd be very unusual, but not impossible.
You're using the right primers? I'm guessing they should be large rifle magnum primers? Any chance they're not? Cold weather and weak primers wouldn't help the situation.
You may simply have a situation that can't be easily resolved. My 243 load using IMR4831 was like that. It went from fine to filthy with not much, if any, in between.
I just got back from the range.
This brass is once fired, FL sized and trimmed at 2.485.
V160 63 g to 66g
Berger 140 vld hunting.
Federal gold metal Large Rifle magnum primers.
My chronograph, which I just purchased off the EE,wasn't working properly.
But I'm pretty sure the speed was correct ,because at one grain over max (67 g) the primers were flattening out.
I thoroughly cleaned the chamber and I ditched the short brass.
The fouling has disappeared, for the most part. There was a bit around the neck mostly, but hardly any on the rest of the case.
So,I think it's a powder issue and nothing to do with the brass.
As you can see from the pics, theres still a bit of carbon on the brass,but not nearly as much,from the shortened,6 time fired brass and the dirty chamber.
I just got a headspace comparator kit,a 7mm neck die and a 7mm collet neck sizing dies.
Now that this once fired,FL sized brass ,has now been fire formed to my chamber, I'm going to learn how to use those tools.
View attachment 473973
This brass is once fired, FL sized and trimmed at 2.485.
V160 63 g to 66g
Berger 140 vld hunting.
Federal gold metal Large Rifle magnum primers.
My chronograph, which I just purchased off the EE,wasn't working properly.
But I'm pretty sure the speed was correct ,because at one grain over max (67 g) the primers were flattening out.
I thoroughly cleaned the chamber and I ditched the short brass.
The fouling has disappeared, for the most part. There was a bit around the neck mostly, but hardly any on the rest of the case.
So,I think it's a powder issue and nothing to do with the brass.
As you can see from the pics, theres still a bit of carbon on the brass,but not nearly as much,from the shortened,6 time fired brass and the dirty chamber.
I just got a headspace comparator kit,a 7mm neck die and a 7mm collet neck sizing dies.
Now that this once fired,FL sized brass ,has now been fire formed to my chamber, I'm going to learn how to use those tools.
View attachment 473973
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OP, how much are you resizing your brass? If you stated this already, I missed it.
The condition you are getting can come from a couple of conditions that you likely won't have any control over.
Chambers with lots of Freebore and large neck diameters will show this issue.
I had one of the early Griffon&Howe commercial Mausers, chambered for the 300 H&H magnum. Lovely rifle that went to a collector of fine rifles.
This rifle was a purpose built sporting Mauser built in the mid 1930s, for hunting in Africa.
The fired cases would come out all covered in black soot fouling, even with stout loads. New brass was OK, with only the neck covered in residues. The reloads on brass afterwards had the residue right down to the belt, as shown in your pics.
When I re annealed the cases, after three firings, the first shot would leave residue on the neck but the subsequent shots were always covered.
Like you mention, pressures were high enough to flatten primers so that wasn't the problem.
A mentor of mine, told me to check the throat diameter and the chamber diameter at the neck, as well as the freebore to the leade. He knew his stuff and I believe he was bang on.
I don't remember the dimensions. Suffice to say, the neck was on the large side of mean and it had close to 3/4 in of freebore in front of a 220 grain, round nose bullet, seated as far out as the magazine would allow for proper feeding.
He explained that pressures weren't high enough to seal the brass against the chamber to inhibit the gasses carrying the residues, until the bullet actually entered the bore.
There was enough freebore that the bullet had exited the case before entering the bore enough to create a seal, that allowed the pressure to build up enough to allow the case to seal against the gasses.
The condition you are getting can come from a couple of conditions that you likely won't have any control over.
Chambers with lots of Freebore and large neck diameters will show this issue.
I had one of the early Griffon&Howe commercial Mausers, chambered for the 300 H&H magnum. Lovely rifle that went to a collector of fine rifles.
This rifle was a purpose built sporting Mauser built in the mid 1930s, for hunting in Africa.
The fired cases would come out all covered in black soot fouling, even with stout loads. New brass was OK, with only the neck covered in residues. The reloads on brass afterwards had the residue right down to the belt, as shown in your pics.
When I re annealed the cases, after three firings, the first shot would leave residue on the neck but the subsequent shots were always covered.
Like you mention, pressures were high enough to flatten primers so that wasn't the problem.
A mentor of mine, told me to check the throat diameter and the chamber diameter at the neck, as well as the freebore to the leade. He knew his stuff and I believe he was bang on.
I don't remember the dimensions. Suffice to say, the neck was on the large side of mean and it had close to 3/4 in of freebore in front of a 220 grain, round nose bullet, seated as far out as the magazine would allow for proper feeding.
He explained that pressures weren't high enough to seal the brass against the chamber to inhibit the gasses carrying the residues, until the bullet actually entered the bore.
There was enough freebore that the bullet had exited the case before entering the bore enough to create a seal, that allowed the pressure to build up enough to allow the case to seal against the gasses.
Update
Yesterday,with gun thoroughly cleaned, I put 60 rnds of the problematic reloads down range.
Short brass 6 times fired.
140 vld over 66 g 160.
The brass was fouled, but not nearly as bad as before the cleaning. Still unacceptable though.
Today, I put 15 rnds down range, uncleaned gun.
Short brass
150 Nosler ballistic tips over 66g Vithatori 560.
3150 fps
No fouling on the brass.
So with the only change being powder and bullets
,itsnot the gun...whew ..lol
It's got to be the powder.
Yesterday,with gun thoroughly cleaned, I put 60 rnds of the problematic reloads down range.
Short brass 6 times fired.
140 vld over 66 g 160.
The brass was fouled, but not nearly as bad as before the cleaning. Still unacceptable though.
Today, I put 15 rnds down range, uncleaned gun.
Short brass
150 Nosler ballistic tips over 66g Vithatori 560.
3150 fps
No fouling on the brass.
So with the only change being powder and bullets
,itsnot the gun...whew ..lol
It's got to be the powder.
Looks good.
Your right.
I'll do up 5 rnds of min and 5 of max.
Same bullet,same powder,same brass.
Run them over the chrony.
I'll also load 10 rnds,same powder,same brass, different bullet.Just to eliminate if the vld has anything to do with it.
Just a side note.
The 150 Nosler ballistic tips and 66 g vithatori 560 was reading 3150 fps.
And out of the 15 I fired, I got a sticky bolt on 4 of them.
Maybe a bit hot??
