soot and burn marks on case necks

ffwd

ffwd

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Let loose with 60 handloads this morning at the range. Loads were based off of data gathered at last weekend, and yesterdays shooting session.

7mm Weatherby Mag in a Mark V. Once fired Norma brass, 69.5 gr. H4831, 168 gr. Berger VLDs and 160 gr. Sierra GKs
at 100m the bergers grouped 1.25" with both 69 and 70 gr.

40 of 60 rounds fired today at 200m hit the 11" by 11" target boards. The magnum primers were consistently printing 2" higher than the CCI BR-2 primers.

I was aware of the rounds that missed due to flinching, which would account for, well, most of the misses.

All case necks are showing soot and burn marks right down to the shoulder.

Why?
 
first, I am not an expert. I may be wrong on this.

But the rifle cases that I reload & shoot have soot & burns marks. I have always been of the opinion that as long as it goes no further down the case then it is a part of the process of firing the cartridge. Unless the neck & shoulder are a press fit to the chamber, it happens.


I have A Makarov 9mm pistol that has a somewhat loose chamber for reliable feeding & the whole case comes out smokey. The Maks are known for that.
 
My .270 reloads have sooty necks. Same with my .303 and 7.5X55 reloads. I think as long as it doesn't pass the shoulder, it's a-ok.
 
ffwd said:
Let loose with 60 handloads this morning at the range. Loads were based off of data gathered at last weekend, and yesterdays shooting session.

7mm Weatherby Mag in a Mark V. Once fired Norma brass, 69.5 gr. H4831, 168 gr. Berger VLDs and 160 gr. Sierra GKs
at 100m the bergers grouped 1.25" with both 69 and 70 gr.

40 of 60 rounds fired today at 200m hit the 11" by 11" target boards. The magnum primers were consistently printing 2" higher than the CCI BR-2 primers.

I was aware of the rounds that missed due to flinching, which would account for, well, most of the misses.

All case necks are showing soot and burn marks right down to the shoulder.

Why?
Click to expand...

If you are getting carbon fouling (soot) further down the casing than just the neck, you are having a problem. To foul the neck only is normal.
Try a faster burning powder and this will be resolved.
You necks are springing back from the chamber before you bullet has left the barrel, allowing hot gas and carbon fouling back past the neck.
Seating your bullets out further will also help, this will be hard given Wbys massive freebore, having the bullet closer to the lands slightly increased the pressure spike, forcing the powder to burn inside the casing more before the bullet leaves the casing.
Slightly more neck tension will also help solve this, but I would assume you are not using bushing dies.
 
Carbon fouling on the necks only. But WAY more than the guy beside me with the 300 win mag factory cartridges.

Faster burning? I was going to try H1000
I've got data for IMR4831

COL was 3.45" for the good groups. I seated a bullet backwards out as far as I could with hopes of hitting lands, to no avail.

Those rounds were neck sized with a Hornady 7mm neck-sizing die. No bushing dies, no way to measure neck tension except for how many hits it takes to get the projectile out with the kinetic bullet puller.
 
All case necks are showing soot and burn marks right down to the shoulder.
Click to expand...
This is normal to a variable degree depending on several parameters such as neck tension, crimp degree, powder type & burn rate, etc.
All loads, handgun and rifle exibit this gas discoloration to some degree, nothing to worry about if it does not go past the shoulder area.
You necks are springing back from the chamber before you bullet has left the barrel
Click to expand...
This gas enchroachment in the neck area would be occuring as the bullet unseats from the case neck, before the pressure has risen to a sufficient level to yield the brass and seal the neck tight against the chamber wall........this gas sealing process in guns upon firing is called obturation.
 
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