What is "mesh size" for corncob media?

[maillemaker]

So I see I can get a 40 pound bag of corncob media from McMaster-Carr for about $25:

http://www.mcmaster.com/#corn-cob-abrasive-blasting-media/=adh9ze

But it comes in different "mesh sizes". I assume you'd want the smallest. But how do you interpret mesh sizes? Is bigger mesh size bigger or smaller particles?

Steve

 

[Unclenick]

I've seen all three sold for polishing. The coarse is too big and doesn't work well. Both the middle and fine grades will work. I prefer the fine to get more inside primer pockets, though I'm not sure it lasts as long as the 14-20. But that's a subjective impression and not measured in any way.

That stuff is sold for blasting paint off wood and other soft surfaces. You can often find it locally at a sand blasting supply outfit and save yourself the shipping.

 

[res45]

Media size pics http://www.greenproducts.com/corncob_products/ I've use the 1/8" size usually found in pet bedding,works great on 30 cal. and larger or straight wall pistol case and the 1014 as well for anything will smaller size necks like .223/5/56.

No matter which size you use your going to get some media stuck in the flash hole on occasion if you tumble with the primer out. I do a pre and post tumble on my brass before and after sizing,usually a few hundred cases at a time so it not a big deal to clean out a few pieces of media.

 

[maillemaker]

No matter which size you use your going to get some media stuck in the flash hole on occasion if you tumble with the primer out. I do a pre and post tumble on my brass before and after sizing,usually a few hundred cases at a time so it not a big deal to clean out a few pieces of media.

If I run all my brass through my progressive reloader, which attempts to deprime even if it is already deprimed, would that not knock out any obstruction?

Steve

 

[Unclenick]

Usually. That's another reason I didn't like the really big stuff. You can sometimes get a stuck kernel on the inside that is bigger than the flash hole, and which deflects the decapping pin to the side so it hits solid brass. Best to unbend a paperclip and poke those out manually from the primer pocket side. Doesn't take long and you need to inspect cases at some point anyway.

 

[demigod]

No matter which size you use your going to get some media stuck in the flash hole on occasion if you tumble with the primer out.

The last batch of lizard walnut I got doesn't stick in the primer pockets. It's a much finer grit of media.

And media still gets stuck in the flash hole even if the primer is in the case. It just gets punched out when you decap.

 

[jepp2]

If you get the 20-40, they rarely catch in the flash hole, and never plug it. The 14-20 will catch more often and can fill the hole.

You can get a better price on the same bag from DrillSpot:

http://www.drillspot.com/products/521055/econoline_526040g-40_40_lbs_blast_media

 

[maillemaker]

Thanks for the link!

Steve