Fine Corn Cob Media too fine causing stuck cases in full length sizing die?

harbl_the_cat

harbl_the_cat

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I recently transitioned to using 3080 grit corn cob media to tumble my brass that I bought from a sand blasting shop. This stuff is VERY fine, almost like very fine sawdust. It leaves a nice, beautiful finish (compared to Walnut). Compared to my Lyman red walnut media, a single kernel is probably 1/10th in size.

It also kicks up a LOT of very fine dust - much more than with Walnut - and even a dryer sheet doesn't help.

Previously, I had resized about 50 cases of .308 no problem and probably 1000 .223 cases using a liberal coating of Lyman Quik Spray - but it's only been since I transitioned to the fine corn cob media that I've had this problem.


I started full length sizing .308 and .223 brass - and the results have not been very good. I have mangled several pieces of .308 brass, my mostly new .308 die, and last night my first .223 case in a Lee full length sizing die that has seen roughly 1000 cases.

My theory is the media is so fine that some grains and/or media dust are staying in the casing, gumming up the sizing die.

I'm going to retumble all my rifle brass in Walnut and see what happens - but anyone else had this problem?
 
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I switched to a fine walnut mix and found that, while I was getting less stuck in the flash hole, I was getting more cases with a semicompacted wad inside. It turned out to be not that much of a problem, however. When I'm taking the cleaned cases out of the basket, I just hold them up to the light. If there's light inside, they're empty. If not, just tapping them upside down seems to clear the clog quite well.

I can see that any kind of grit on the outside of a case might cause binding in a sizing die. If the grit (just a little, not packed, ie) is on the inside however, I can't see it making that much difference. I normally lube my necks using lead shot and graphite, so any dust left over from cleaning is knocked off inside the neck, where the sizing ball might get stuck.
 
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seriously consider an ultrasonic cleaner of eBay. a bit of dish soap and lemmi shine and they are great, including the primer pockets. If you really want to do it right, consider stainlesssteelmedia.com Walnut and corncob just make them look pretty
 
I have used media that leaves a fine dust. Inside the case should not affect the die (maybe the expander ball) because it is in the case not on the case and shouldn't touch the die. As far as being on the outside of the case I use an old towel to wipe off the dust by rolling them all around in the towel before lubing. I would try a different lube like Redding Imperial Sizing Die Wax or RCBS Case Lube II on a lube pad instead of the spray on lubes.
 
hk33ka1 said:
I have used media that leaves a fine dust. Inside the case should not affect the die (maybe the expander ball) because it is in the case not on the case and shouldn't touch the die. As far as being on the outside of the case I use an old towel to wipe off the dust by rolling them all around in the towel before lubing. I would try a different lube like Redding Imperial Sizing Die Wax or RCBS Case Lube II on a lube pad instead of the spray on lubes.
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+1 on that. Great stuff.
 
joe-nwt said:
Which is all you really need.
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When used for hunting and fun, I couldn't agree more, and I have varmint brass that has never seen the inside of a tumbler. for precision long range shooting (TR, BR, F-Class) it is important to standardize primer seating pressured and internal case capacity/pressure. Hell, its important to standardize everthing for long range precision.
 
hk33ka1 said:
I have used media that leaves a fine dust. Inside the case should not affect the die (maybe the expander ball) because it is in the case not on the case and shouldn't touch the die. As far as being on the outside of the case I use an old towel to wipe off the dust by rolling them all around in the towel before lubing. I would try a different lube like Redding Imperial Sizing Die Wax or RCBS Case Lube II on a lube pad instead of the spray on lubes.
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Thing is, I've loaded probably 2 - 3k .223, 7.62x39, and a .308 using Lyman Quik N-EZ no problem.

It's only been since I've switched to this fine corn cob media that I've had problems. The thing about the media though, is that the grains are so small, it's even hard to see them. I've poured out a handful of casings that I THOUGHT I had emptied, and a few flakes of the media have come out.

This is what it looks like:

8_21.jpg


Alternatively, this same company sells Walnut:

19_35.jpg


I'm retumbling everything with walnut and will give an update when I get sizing again.
 
Suputin said:
Keep in mind that fine dust will contain lead contamination. You prob don't want to breathe that or track it through your home.
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I reload in my detached garage, wear a P100 when I empty and fill my tumblers, do so at the entrance of the door (with the door open). When reloading I generally wear coveralls, an apron or an outer shirt that doesn't come into the house and almost always wear rubber mechanics gloves. I always wash my hands or shower using D-lead after an intense bought of reloading. I also wash all my reloading/shooting clothes in a separate load from my families normal laundry, using D-lead detergent.
 
I retumbled all my .223 and .308 brass with walnut and tried resizing in a completely new .308 and .223 die.

No problem - there were a few sticky cases, but no stuck ones.

I'll keep tumbling with walnut and resizing with the same dies. I think there might be another variable - the temperature. I resize in a semi-heated shop in my garage, and it was starting to get a bit chilly out. In the room, I think it was 14-15oC - which itself doesn't seem too cold, but could be a possible factor. Right now though, after bricking two dies, I'd rather not take the chance with the fine media.

I'll keep posting as more developments come up.
 
Cool. Might I suggest that you just take HK33kA1's advice and just toss the tumbled cases in a towel before sizing? (I use the sleeve from an old flannel shirt.) That should take off the grit. If on the other hand you are happy with crushed walnut, fill yer boots, byes.

I doubt that a 5° change in temperature (room temp being a nominal 20°) would change the characteristics of brass (melting point exceeding 900°C) very much. Possible, but I would suggest the dust is the primary issue.

Good luck - interesting to watch your experiements.
 
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