What is causing the fouling on case neck and shoulder?

[RedRyder]

This is the 3 re-load for these 264 Win Mag cases. However, I've been seeing a lot of fouling on almost all of the cases from this rifle no matter if they're virgin brass or not. It seems to have gotten worse lately though. Sometimes the entire neck and shoulder are fouled 360 degrees. Can anyone give me a reason or reasons this may be happening? I full-length re-size btw.

I tried to take the best photos I could for illustration.

TIA for your suggestions.

 

[Evintos]

This is the 3 re-load for these 264 Win Mag cases. However, I've been seeing a lot of fouling on almost all of the cases from this rifle no matter if they're virgin brass or not. It seems to have gotten worse lately though. Sometimes the entire neck and shoulder are fouled 360 degrees. Can anyone give me a reason or reasons this may be happening? I full-length re-size btw.

I tried to take the best photos I could for illustration.

TIA for your suggestions.

My guess: work hardened brass/case necks not allowing the brass to expand to seal the neck/throat. Requires annealing.

 

[lash]

First off, it is common and appropriate for there to be some fouling on the outside of the neck, though ideally it should not extend down onto the shoulders. There are some factors that can affect this.

As already mentioned, annealing your brass can allow the neck to flow better when fired. In addition, it’s likely that the load you are using is a bit light. Did you do a load pressure test during load development? With the fouling on the shoulders, I’ll ask how much you are bumping back the headspace and did you measure for proper headspace up front?

 

[Deleted member 113831]

First off, it is common and appropriate for there to be some fouling on the outside of the neck, though ideally it should not extend down onto the shoulders. There are some factors that can affect this.

As already mentioned, annealing your brass can allow the neck to flow better when fired. In addition, it’s likely that the load you are using is a bit light. Did you do a load pressure test during load development? With the fouling on the shoulders, I’ll ask how much you are bumping back the headspace and did you measure for proper headspace up front?

^^^This.

 

[FLIGHT762]

First off, it is common and appropriate for there to be some fouling on the outside of the neck, though ideally it should not extend down onto the shoulders. There are some factors that can affect this.

As already mentioned, annealing your brass can allow the neck to flow better when fired. In addition, it’s likely that the load you are using is a bit light. Did you do a load pressure test during load development? With the fouling on the shoulders, I’ll ask how much you are bumping back the headspace and did you measure for proper headspace up front?

^^^^^^^^^And this again^^^^^^^^^^.

Try annealing, but as long as you're not getting fouling below the case shoulder and getting good velocities and accuracy, I wouldn't worry about it.

 

[RedRyder]

I'm using Retumbo at 67.0 and 67.5 grains. According to "modern" reloading manuals I'm tempting certain global catastrophe with loads that "hot." Yeah, they're hot all right. NOT. I'd say they're mid-weight loads.

 

[Milo 2.5]

The neck dia in your chamber may be to large also. I'd put more powder in, and run tight bump.

 

[Milo 2.5]

It has not been brought up, but once you gas a case, your chamber has some carbon in it also, and the more you keep firing, the worse it gets as now it cannot seal off.
A few of us took to shooting RL16, and controlling the speed can get difficult, so you do not pour the powder to it. We end up gassing chambers more than anything I've seen, it helps to have a cleaning rod and some solvent at the range, do a quick swab.

 

[secondofangle2]

Retumbo is classically known to cause that

 

[RedRyder]

I think I'll try cleaning it.

I didn't know Retumbo was known to cause that. Learn something new every day.

Thanks all.

 

[jsthntn247]

Try only sizing as much of the neck as you have bullet in it. That will help the neck seal off in the chamber. This can only be done with fl bushing dies.