- Location
- Vancouver Island, BC
Does anyone know if tumbling primed brass will ruin the primers? Just pulled 200 9mm and I really don't want to re-prime them if I don't have to. It's purely a cosmetic thing but hey, I like shiny things.
Tumbling primed brass
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Well, every time I tumble brass, I wind up with c*** in the primer hole.
Maybe it would be knocked out of the way by the primer firing 99.99% of the time. You can go first.
Maybe it wouldn't interfere with ignition. Maybe.
My personal call is that if it's purely cosmetic, ignore it and remember next time.
Maybe it would be knocked out of the way by the primer firing 99.99% of the time. You can go first.
Maybe it wouldn't interfere with ignition. Maybe.
My personal call is that if it's purely cosmetic, ignore it and remember next time.
Ditto
First; depending on what you use for media it can and will get stuck in the hole and eventually this will cause a miss fire.
Second; if you add anything to the media (brasso/etc..) it could be absorbed into the primer (highly unlikely I think though-depends on how much and when it was put in).
Third: tumbling your loaded rounds not only makes them shiny but it also removes the sticky case lube.
Tumbling a loaded round, especially one where the powder doesn't fill the cartridge, can cause the powder to break down into a finer particle size. This can significantly increase the firing pressure, with obvious implications for safety/reliability.
^^ What he said. I tumble my brass to get them clean, resize, then throw them in the tumbler for 5 minutes to get all the lube off. Lee Case length gauge cleans the little bits out of the odd flash hole.
To the OP: suck it up buttercup
It'll be way easier in the long run to just shoot 200 less than pristine looking rounds. Besides, 200 rounds? You'll only have to suffer looking at their ugliness for about 10 minutes
To the OP: suck it up buttercup
It'll be way easier in the long run to just shoot 200 less than pristine looking rounds. Besides, 200 rounds? You'll only have to suffer looking at their ugliness for about 10 minutes 
stevesummit
CGN Regular
- Location
- spruce grove
Let him have his fun. Plus they shouldn't have been? Baggage handlers are the genteelest people I know man.
Exactly, I've heard the powder breakdown theory, but I've never found anyone who can prove it.
I have read where guys have tried it, tumbling for varying amount of times going into days and test firing with chronographs and not finding any differences in velocity.
The powder bounces against itself in the powder tin all across the country to your house, and then bounces against itself in the cartridge for however long before being used. Think about the miles military ammo puts on by the time it's warehoused and transferred around, shipped overseas etc.
That all said I don't tumble my loaded ammo for days at a time, but for half hour or better, and I've never seen any trouble.
I wouldn't tumble primed cases, way too much chance of gunk clogging the flashhole. I usually keep a nail handy while priming just to clear junk out of the flashholes that got stuck during tumbling. You should have tumbled them before you pulled them, if it was that important.
I've thought about tumbling my finished pistol rounds in order to clean off the light coating of dry (but still tacky) LLA the lead cast bullets were tumble-lubed with. I'm just wondering if that would ruin my corncob media or make it less effective for actual brass cleaning.
That's the primary reason I tumble loaded ammo. I use a little bit of mineral spirits on the media, and it works great. Corncob definately works better for that then walnut. 10 - 15 minutes is usually enough.
I use separate media for cleaning brass and cleaning loaded ammo.
I'm sure they've been shaken. I doubt they've been tossed in a mechanical vibrator for several hours.
I'm not particulary worried about a round going off if I drop it on a hard floor. Doesn't mean I think it's a good idea to drop it a few thousand times. And even if I did do that and nothing happened, I wouldn't automatically assume that it's perfectly safe and start recommending it to others.
The "powder breakdown theory" is rational and fits into our understanding about the physics of the materials. Unless you've got evidence that it's false (and "I tried it and my gun didn't blow up" isn't good evidence), then I think it's reasonable to obey the warnings on our tumblers which universally tell you not to tumble live rounds.
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- Location
- In the middle of gopher country
or have been under the seat of my truck for more than a few years. I'm thinking that adds up to way more shake time than several hours in a mechanical vibrator. As in multiple of tens times.
So where is all the universal evidence that tumbling causes powder to break down? Any chance the universal warning is a generic "cover-your-ass" warning?My advice to the OP is to load up the brass as is, don a pair of sunglasses so no one will recognize you shooting dull brass, and fire it off. Maybe go to the range late in the evening when there is less chance that someone will see you. THEN collect your brass and tumble to your heart's content. Less chance of a hang-fire/misfire due to a clogged flash hole. Really we're talking about $7.00 worth of primers here. Not that important in the grand scheme of things, right?
Very interesting. I actually have another tumbler here that's not doing anything. Perhaps I should dedicate it to the purpose and not worry about changing media. How many rounds do you tumble at once, and how much mineral spirits do you use per batch?
The mineral spirits don't bother the primers?
I'm sure it's more CYA than anything else -- but the fact that tumbler manufacturers care more about not being sued than whether you blow up your gun or not doesn't make the warning wrong. I do admit that the only "empirical" evidence I've run across for over-pressure due to powder break-down are the anecdotal "I know I guy who knows a guy who..." type that I tend to ignore.
However, I also know that smokeless powder granules will fracture under friction and that subjecting material like that to a lot of collisions (as is going to happen in tumbling) will cause it to break down somewhat. I also know that, other things being equal, powder in flake form will generate gas faster than in rod or ball form (fracture is much more likely in large particles, and they have more mass in collision), and that finer particles will generate gas more quickly due to more surface area. This supports the idea that tumbling powder could cause it to generate finer particles, and potentially more pressure. Now, obviously, this is going to have a lot of variables -- I expect it would be less of a concern for ball powder than rod, and even less for flake. It would also be less a concern in cartridges that are full or nearly full (so the mean path between collisions is very small), etc.
In general, when safety is a concern, you should assume worst case, so I don't tumble live rounds. And I won't until someone explains to me the flaw in the model described above.
