Excessive carbon on 7mm case? Update.
- Thread starter 45C
- Start date
I would respectfully suggest you stop and reconsider. There are several unexplained issues.
1- The original problem was never figured out, a load of N-160 that should have been fine gave very strange carbon deposits. Also the cases "shrinking" again very strange with a belted magnum that is being fully resized.
2- Now a sticky bolt and velocities that are too high for the powder charge of N-560.
3- Why is the N-160 a big problem and 560 just fine ? They are single base vs double base but very similar in burning rate so why the huge difference.
4- In your original post #1 of this thread it looks like this case has a partial case head separation, this is very common in belted magnums and almost always happens at reload 5
5-If Ganderite is telling you your pressure is too high stop and listen.
Not trying to pee on your parade but something is very wrong with this gun and these reloads.
1- The original problem was never figured out, a load of N-160 that should have been fine gave very strange carbon deposits. Also the cases "shrinking" again very strange with a belted magnum that is being fully resized.
2- Now a sticky bolt and velocities that are too high for the powder charge of N-560.
3- Why is the N-160 a big problem and 560 just fine ? They are single base vs double base but very similar in burning rate so why the huge difference.
4- In your original post #1 of this thread it looks like this case has a partial case head separation, this is very common in belted magnums and almost always happens at reload 5
5-If Ganderite is telling you your pressure is too high stop and listen.
Not trying to pee on your parade but something is very wrong with this gun and these reloads.
I've had a few case head separation, I dont see the ring around case yet.
I could only find one recipe for the 140 g bullet and n560.
That was off Vithatori website.
It listed a 140 g scirocco with a max load of 67.3 g n560.
With an MV of 3169.
So,I got basically the same speed with 1.3 grain less powder.
The bolt stuck on 4 four of the 15 cases.
The rest were smooth as butter.
Also I've had the bolt stuck a lot worse than that.
I'm now only going to chrony the 140 Berger over the min load of 63 g of n160,as per Bergers recommended min load.
I also had a friend take a look at the brass,hes been reloading for decades.
Hes also of the opinion that its powder related.
But who knows and in any event, its not the end of the world.
45c, it's been my experience as well as that of others, to find the most rifles chambered for magnum cartridges, bordering on or are actually overbore capacity, that the best performance is very close to maximum loadings.
Some folks scoff that the 7mm Rem Mag isn't overbore capacity. Yes, it is. Same argument with other cartridges, such as the 25-06, but not so much.
If you can get your 7rem mag to shoot well at lower pressures, without issues, go for it.
I gave up on magnum cartridges over two decades back. They seldom could be depended on to give me the accuracy I like and they beat the hell out of me while trying. They did everything they claimed to do on impact with soft/bony tissue.
Trying to load them down to tolerable for me recoil was a waste of my time and powder.
Your pics don't show excessive case expansion. I don't remember how much you resize your cases or how often you re anneal your cases. By the time they've been fired six times, that brass is HARD and just might not be able to expand enough to seal around the case.
If you don't want to be bothered with re annealing, then IMHO it's definitely time for new cases. You're not gaining any knowledge beating a dead horse, which those 6X cases are.
Some folks scoff that the 7mm Rem Mag isn't overbore capacity. Yes, it is. Same argument with other cartridges, such as the 25-06, but not so much.
If you can get your 7rem mag to shoot well at lower pressures, without issues, go for it.
I gave up on magnum cartridges over two decades back. They seldom could be depended on to give me the accuracy I like and they beat the hell out of me while trying. They did everything they claimed to do on impact with soft/bony tissue.
Trying to load them down to tolerable for me recoil was a waste of my time and powder.
Your pics don't show excessive case expansion. I don't remember how much you resize your cases or how often you re anneal your cases. By the time they've been fired six times, that brass is HARD and just might not be able to expand enough to seal around the case.
If you don't want to be bothered with re annealing, then IMHO it's definitely time for new cases. You're not gaining any knowledge beating a dead horse, which those 6X cases are.
Yes,I've tossed those cases and got a couple hundred once fired.
I've also started annealing and will annealing the new cases once they are fire formed.
I want to test the load data for mv,Berger gave me min and max loads,but no other info.
So ,that's the only thing left.
The only reason I bought the Berger was because I couldn't find any Nosler ballistic tips.
I also picked up a neck die, and a comparitor set.
Hey guys
I'm only doing this out of boredom.
I own a small exterior renovation company and this is the first winter I've had off ,in 15 years.
On top of that,the kids have been home,online schooling and the wifes mom passed away last week.
So I'm going bonkers ..lol
I'm not being unsafe , just experimenting, on the safe side.
Anyway,I'm almost done with this.
I just want to test the speed and try the the bullet/ powder combo ,using new brass.
That way ,I'll know if its brass or powder that's causing the carbon.
My friend says powder, but I'm with Bearhunter, that it's the brass.
It's been FL sized so much,that it's not sealing correctly.
Thanks to all who offered advice
I listen to it all,especially from Gander,Dave,Eagle,Bear,etc.
And their advice has helped me many times in the past.
I'm only doing this out of boredom.
I own a small exterior renovation company and this is the first winter I've had off ,in 15 years.
On top of that,the kids have been home,online schooling and the wifes mom passed away last week.
So I'm going bonkers ..lol
I'm not being unsafe , just experimenting, on the safe side.
Anyway,I'm almost done with this.
I just want to test the speed and try the the bullet/ powder combo ,using new brass.
That way ,I'll know if its brass or powder that's causing the carbon.
My friend says powder, but I'm with Bearhunter, that it's the brass.
It's been FL sized so much,that it's not sealing correctly.
Thanks to all who offered advice
I listen to it all,especially from Gander,Dave,Eagle,Bear,etc.
And their advice has helped me many times in the past.
Berger 140 VLD
63 g Vithatori ( min load)
7 times fired brass trimmed to 2.470.
FL sizedView attachment 475230
And they're actually 140 gr? It wouldn't be the first time the wrong bullet went in the box. Other than that, the extra 10 gr of the Noslers is maybe enough to make a difference. It'd be interesting to know what the difference in pressure is. The 150's probably have a longer bearing surface as well, so more friction.
The Bergers have comparatively short bearing surfaces, plus they are generally quite soft [thin jackets]
They do not build pressures as quickly as conventional hunting bullets do.
I do not feel that 3150 is excess velocity with the 150 NBT. One more factor that may be contributing is,
over the years, 7mm Rem Mag chamber dimensions have varied a considerable amount, allowing some 7mm
mags to accept larger charges of powder than others. VVN560 is in reality, somewhat slower burning than
is VVN160 [Closer to VVN165 in my experience]
My present 7mm Rem Mag, an older 700 [1970's] dotes on a 160 grain Accubond load. 67.0 grains of Norma
MRP, in a WW Super case, fired by a WLRM primer, with a .020" jump to the lands. No brass or primer pocket
issues in my rifle, and sub-moa right out to 500 meters. Dave.
They do not build pressures as quickly as conventional hunting bullets do.
I do not feel that 3150 is excess velocity with the 150 NBT. One more factor that may be contributing is,
over the years, 7mm Rem Mag chamber dimensions have varied a considerable amount, allowing some 7mm
mags to accept larger charges of powder than others. VVN560 is in reality, somewhat slower burning than
is VVN160 [Closer to VVN165 in my experience]
My present 7mm Rem Mag, an older 700 [1970's] dotes on a 160 grain Accubond load. 67.0 grains of Norma
MRP, in a WW Super case, fired by a WLRM primer, with a .020" jump to the lands. No brass or primer pocket
issues in my rifle, and sub-moa right out to 500 meters. Dave.
From everything we've talked about, it sounds like the 140 VLDs are not quite enough of a payload for either N160 or 560.
The extra 10 grains of bullet weight and longer bearing surface/thicker jacket of the Nosler may be just enough to clean it up and get better sealing in the chamber.
Kind of a perfect storm situation. Just enough of several different conditions coming together to cause a problem.
Some feedback to Berger about your experiences with this load might be a kind thing to do, if they're still in the development stages. I'm surprised they even suggested using it if they weren't finished with it.
The extra 10 grains of bullet weight and longer bearing surface/thicker jacket of the Nosler may be just enough to clean it up and get better sealing in the chamber.
Kind of a perfect storm situation. Just enough of several different conditions coming together to cause a problem.
Some feedback to Berger about your experiences with this load might be a kind thing to do, if they're still in the development stages. I'm surprised they even suggested using it if they weren't finished with it.
I tested the 140 vld with 560,same results.
Besides that,I only have 2 VLDs left and I'm not buying anymore. Lol
I loaded 15 rounds of 150 Nosler BT ,with the V160.
5 rounds per group ,consisting of 60,62,64 grains.
No fouling at all.
Here's a pic of the three groups.
The corners.
The 64 g looks promising?
