Case fouling on shoulder/neck

[Namibia]

Good evening Gents,

Can someone maybe assist me with the following problem. A friend of mine reloads for a .300Win Mag. using Sierra GK 180gr, and Prvi Partizan Brass. He assured me that the charge is well below max according to the manual. (I don't have the exact charge and type of powder though)

After firing his loads, there's quite a bit of powder fouling on the shoulder area of the case (on the outside of the case, off course), as well as on the neck area. Seems like some of the gas is leaking "back" past the neck during firing resulting in a "burnt power residue". This doesn't occur further down the case past the shoulder egde.

He shoots a Ruger M77 Hawkeye, and the rifle is brand new.

Your imputs will be much appreciated.

Thanx

Pieter

 

[jeffro]

Quote - He assured me that the charge is well below max according to the manual.

This will sometimes cause this as the case is not sealing with the low preasures that are produced at low charges.

 

[Broz]

I started to see this before after about 4 firings as the brass was work hardening and not sealing good. This was when I started annealing necks and it curred the problem. So depending on your times fired it could be it.

Jeff

 

[jeffro]

I started to see this before after about 4 firings as the brass was work hardening and not sealing good. This was when I started annealing necks and it curred the problem. So depending on your times fired it could be it.

Jeff

That will cause it as well. Good point.

 

[Tucker943]

My Hawkeye 7 mag did the same thing when i was running some hardened brass though it. Fresh or annealed brass will almost certainly solve the issue.

 

[J E Custom]

Good evening Gents,

Can someone maybe assist me with the following problem. A friend of mine reloads for a .300Win Mag. using Sierra GK 180gr, and Prvi Partizan Brass. He assured me that the charge is well below max according to the manual. (I don't have the exact charge and type of powder though)

After firing his loads, there's quite a bit of powder fouling on the shoulder area of the case (on the outside of the case, off course), as well as on the neck area. Seems like some of the gas is leaking "back" past the neck during firing resulting in a "burnt power residue". This doesn't occur further down the case past the shoulder egde.

He shoots a Ruger M77 Hawkeye, and the rifle is brand new.

Your imputs will be much appreciated.

Thanks


Hardened case necks,slow burning powder and lower/slower powder charges can all contribute
to this condition.

J E CUSTOM

 

[trueblue]

You were given good answers. All of the above.