Wet tumbling with stainless pins are causing a burr on insidevof my case mouth.

[Tall]

Do you wet tumble with stainless media? I have noticed that when I wet tumble my cases form a burr on the inside of my brass case in the mouth. If the burr isn't removed it will cause over pressure and could cause primer pockets to blow or pierce primer. I am curious if anybody else experienced this. Have you seen this with dry stumbling?

 

[victor3ranger]

I have heard of this before, need to debur inside and outside of the case mouth before loading

 

[Tall]

I have heard of this before, need to debur inside and outside of the case mouth before loading

I chamfer and de burr each time, it just seems like allot. Wondering if dry tumbling in dry media might be better.

 

[MagnumManiac]

Please explain or show evidence of a case burr causing excessive pressure.
I have a Pressure Trace, heavier and heavier crimping caused a SLIGHT rise in start pressure and an overall rise in Max Pressure in the order of no more than 8,000psi, no matter how hard I crimped.
What loads are you running to have blown primers with a case mouth burr?
I don't know anyone that de-burrs their cases every time they reload, after trimming, yes, but why after every reload??

Cheers.

 

[victor3ranger]

I chamfer and de burr each time, it just seems like allot. Wondering if dry tumbling in dry media might be better.

I really like how clean the pin tumblers do but even with dry tumblers I still chamfer inside and out

 

[PddPdd]

Do you wet tumble with stainless media? I have noticed that when I wet tumble my cases form a burr on the inside of my brass case in the mouth. If the burr isn't removed it will cause over pressure and could cause primer pockets to blow or pierce primer. I am curious if anybody else experienced this. Have you seen this with dry stumbling?

How long are you wet tumbling your brass?

 

[Pdyson]

I have noticed that wet tumbling beats up the case mouth, especially with long tumbling sessions over an hour or two. I always chamfer and debur, so I never noticed a difference in pressure or velocity. I didn't like the case mouth damage so I limit my cleaning to 45 minutes. It's not as shiny but still squeaky clean except for the primer pockets. Further, only a light chamfer and debur cleans them up. My testing tells me clean primer pockets are insignificant for accuracy or precision.

 

[FireFlyFishing]

I deprime my brass, and then run it through wet tumbling. How long depends on how many cases I need to wash. Next, I resize and trim if needed. I inspect the case mouth and pretty much always chamfer and debur. I never have any of the issues you describe.

 

[Laelkhunter]

Might be tumbling too long?

 

[Eric H]

I chamfer and debur every single piece of brass before loading. I did that even when i dry tumbled. Who doesn't?

 

[Varmint Hunter]

I've owned a Rebel STM tumbling kit for quite some time. I only wet tumble cases occasionally. One thing that I learned about SS pin tumbling is that "less is more". You can tumble for 2 hours and get brass that literally looks better than new. However, it will remove all the carbon from the inside of the necks and ding up the case mouths. Or .... you can tumble for 20-30 min and get clean cases that still have the carbon in the necks and case mouths that look much better. A really quick chamfer to touch-up the inside of the neck is a good precaution that may, or may not, be needed.

 

[lyle2231]

I've owned a Rebel STM tumbling kit for quite some time. I only wet tumble cases occasionally. One thing that I learned about SS pin tumbling is that "less is more". You can tumble for 2 hours and get brass that literally looks better than new. However, it will remove all the carbon from the inside of the necks and ding up the case mouths. Or .... you can tumble for 20-30 min and get clean cases that still have the carbon in the necks and case mouths that look much better. A really quick chamfer to touch-up the inside of the neck is a good precaution that may, or may not, be needed.

The RCBS wet tumbler I use says to limit time to 30 - 45 minutes. I've not experienced any neck mouth damage.

 

[338 dude]

I went tumble not every time, but I do it. You need to tumble less and wet tumbling is known for peening case mouths.

 

[Tall]

Please explain or show evidence of a case burr causing excessive pressure.
I have a Pressure Trace, heavier and heavier crimping caused a SLIGHT rise in start pressure and an overall rise in Max Pressure in the order of no more than 8,000psi, no matter how hard I crimped.
What loads are you running to have blown primers with a case mouth burr?
I don't know anyone that de-burrs their cases every time they reload, after trimming, yes, but why after every reload??

Cheers.

I had some new brass that was trimmed and chamfered on a v3 case trimmer. While it looked like it was properly chamfered I was getting primer pockets blowing out. Trying to figure out why I had pressure, I noticed the burr when inspecting the brass. Taking any small tool or knife point when I run it up the case mouth on the inside it was catching and hanging up. After removing the burrs and re testing, all my problems went away. I started inspecting brass right after tumbling and found the burr came back. That is why I'm chamfering every time. To make a long explanation shorter that was my conclusion that the wet tumbler and stainless pins caused the problem.