Brass buildup in sizing die causing scratching.

[entoptics]

Wondering how many of you have seen this behavior, what might lead to it (and prevent it), and what you do to remove it. It's not from an obvious bur in the die itself. It's brass being deposited and building up.

It's scratching the crap out of the brass. I've had it happen a few other times, and can't figure out what's different that causes it. As mentioned, it happens in different places to different extents in different dies, so I don't think it's a badly machined die.

It's a real PITA. It slowly builds up, and scratches the brass worse and worse till I notice it. By that time, I have a bunch of scratched brass, and a gob of brass to remove. I've gotten rid of it with Sweets/Steel wool/elbow grease/sand paper/etc. Takes forever and halts my production. I also don't like "honing" my dies any more than necessary.

Driving me crazy, as I'm in a hurry to get some 270 loaded for my Xmas travels.

 

[venatic]

A shotgun brush with a patch smeared with JB Bore cleaner installed in a drill seems to do the trick quick.

 

[entoptics]

A shotgun brush with a patch smeared with JB Bore cleaner installed in a drill seems to do the trick quick.

Don't have any JB, but I just tried a nylon chamber brush with some Simichrome, and it came out like lightning. 15 seconds on high speed got most of it.

Thanks for the speedy solution!

Stills wondering why it happens in the first place. Seems kinda random.

 

[corsair4360]

I would suspect a small burr or imperfection in the die inner surface caused the buildup....

 

[entoptics]

I would suspect a small burr or imperfection in the die inner surface caused the buildup....

That was my initial theory, but it seems random and rare, and doesn't appear to happen in the same place. I think this is the first time it's happened in my 270 dies (not positive). I'm 99% sure it's happened a couple times in my 300 WM and 223, and again, from what I remember, it wasn't the same amount or place.

I'm planning to run a big batch of 556 soon, so I'll try the "simichrome on a stick" trick and see if the problem goes away.

 

[birdiemc]

I've had this problem because I dont polish my brass, but a little scotchbrite cleans it up real quick. I just have to remember to clean my dies out pretty regularly...in fact glad you brought this up, great reminder

 

[MagnumManiac]

I polish my dies inner surfaces, never get brass build-up because I clean mine with very hot water after each use.

I load for a buddy in HIS dies...They are what I would call FILTHY dirty...carbon build-up, brass build-up and lube inside that die is atrocious at best...he doesn't want them cleaned.
He thinks dirty is good for concentric brass...doesn't even polish expanders.

Cheers.

 

[entoptics]

I polish my dies inner surfaces, never get brass build-up because I clean mine with very hot water after each use...

What's your cleaning regime? The "very hot water" intrigues me.

I've cleaned mine in a variety of ways over the years, and each seems to have a few drawbacks. I'm now mostly "random oily substance, sprayed on a patch, on electric drill stick, then a garnish of carb cleaner! GET ER DUUNNN!".

 

[MagnumManiac]

I run kettle water through the die, letting it run into a bowl, for want of a better word, then let the die sit in that water for a minute or so.
Then, while still too hot to hold in bare hands, I run a 12 gauge cotton bore mop in a drill and spin it in the die.
This dries whatever water may be left, and the bore mop has some flitz polish left on it, which keeps the crud at bay.

I discovered a long time ago that dirty dies make bad cartridges...so I clean after every use, which may be 100-200 cases sized, either with wax or water based lube. EVERY part is pulled down and cleaned.
I mostly use RCBS & Foerster Comp dies, Redding Comp sweaters and a few Whidden dies for specialty cartridges I use.
They all get cleaned the same way and my dies look new even after thousands of sizings/seatings.

Cheers.

 

[corsair4360]

I run kettle water through the die, letting it run into a bowl, for want of a better word, then let the die sit in that water for a minute or so.
Then, while still too hot to hold in bare hands, I run a 12 gauge cotton bore mop in a drill and spin it in the die.
This dries whatever water may be left, and the bore mop has some flitz polish left on it, which keeps the crud at bay.

I discovered a long time ago that dirty dies make bad cartridges...so I clean after every use, which may be 100-200 cases sized, either with wax or water based lube. EVERY part is pulled down and cleaned.
I mostly use RCBS & Foerster Comp dies, Redding Comp sweaters and a few Whidden dies for specialty cartridges I use.
They all get cleaned the same way and my dies look new even after thousands of sizings/seatings.

Cheers.

Thanks for the suggestions (all of them), I need to start cleaning dies.... never thought about it until today, me bad, and I have a bunch of dies...while moving my shop

 

[rsmithsr]

clean brass BEFORE sizing

 

[corsair4360]

clean brass BEFORE sizing

I agree and do it now, have vacillated doing it before, thanks for motivating me to look

 

[entoptics]

clean brass BEFORE sizing

I always wet tumble for 20-30 min with dish soap, though often without the SS pins.

 

[bigedp51]

Stills wondering why it happens in the first place. Seems kinda random.

Any dirt, grit or carbon on the case can become embedded in the die, it then starts picking up brass.

This can be a big problem with any firearm that throws perfectly good brass away and makes you go look for it after it hits the ground. My AR15 brass would scratch my dies until I started wet tumbling and scrubbing the fired case clean.

To polish the die I use a snug fitting shotgun cleaning mop with J&B Bore paiste, automotive rubbing compound, Mothers Mag & Wheel polish, etc. If you are lazy you can just throw the die body in a vibratory tumbler with treated walnut media and let it tumble overnight.

Below a Redding bushing picking up brass from embedded grit or carbon.