Been doing it for years.

I will just leave this here.

http://www.americanhunter.org/blogs/tumbling-ammo-dangerous



Is Tumbling Loaded Ammo Dangerous?



By Keith Wood (RSS)

October 10, 2012







By Keith Wood

The Statement
Tumbling loaded ammo will cause the powder to physically degrade and result in dangerous pressure increases.

The Theory
This is one of those “truths” that’s been repeated over time to the point that it’s considered gospel and at first glance sounds reasonable—classic BullShooters territory. The theory is that the vibration of the case tumbler will break down the construction of the “kernels” of powder, causing different burn rates. The deterrent coating on the powder will also “rub off,” causing the powder to burn more quickly which will raise pressures. A quick Internet search will produce plenty of examples of this “truth."

The Flawed Reasoning
Loaded ammo travels around the country on trucks, powder spends weeks bouncing and rocking across oceans in barrels coming from places like Australia, and belts of linked ammo spend hours shaking violently across the sky in military helicopters, all of which would create similar vibratory forces as a case tumbler.

The Expert Deferral
Logic alone isn’t enough when it comes to harnessing propellant gases mere inches from a shooter’s face, so we asked experts at two of the World’s leading powder and ammunition makers. I spoke to the Chief Ballistic Scientist at Hornady Manufacturing and the Head Ballistician at Hodgdon Powder and asked for their professional opinions. Both agreed that this is a myth devoid of empirical data.

"Powder is hard, it doesn’t change shape from any reasonable amount of vibration,” said Hornady’s Dave Emary. “This notion that you can wear deterrent off of the surface of the powder is a myth, it is impregnated into the powder grains. You can’t knock this stuff off."

Both scientists felt that tumbling was a safe practice within the bounds of reason.

The Ruling
We are calling BullShooters on this one. While extended tumbling could, at some point theoretically cause a problem, a reasonable amount of tumbling to clean up loaded ammo is not dangerous.

I've been doing it for years as well, and even then I only do it if the ammunition is truly dirty or has lube on it.

I also post tumble ammo that I'm going to store in lizard litter and a Frankford vibe for a finish polish.

No problems to date!

How are you supposed to get the lube off after you are done reloading?

Perfectly safe.  If anyone can show me where loaded ammo blew up in their tumbler I would be very highly impressed.

tumbling loaded ammo is dangerous? bullshit in the extreme.

http://www.ar15.com/forums/t_1_5/989047_Tumble_live_ammo_Tumbler_Oandapos__thruth_EXTREME_edition__200hour_torture_test__UPDATE__fired_rounds_in_OP.html

next up, putting your thumb behind a glock slide will get your thumb broken.

Link made hot.  AeroE

Tumbled live ammo here for years also.

No bangs, booms, fires, explosions, end of the world events, etc.

Will continue to do so with confidence.

No problem here either after thousands of surplus rounds through the tumbler to clean em up...

I cut this specific pair of sentences out of the article for a reason.

During Hurricane Irene we took about 4' of storm surge in our walk out basement.  Out of all of the GI ammo cans I had stored there, one had a missing hinge pin and leaked, letting some moisture in the cans which was absorbed by the boxes in some of the factory boxed ammo and/or held agains the rounds in the a few that that had styrofoam liners.  It took several days to get around to inspecting that box and by that time there was a fair amount of general ick on three boxes of ammo in that can.  

They went into the tumbler and ended up being tumbled for about 48 hour total, removing the salt residue and verdigris, but not the staining itself.  A couple weeks later when I expended them on the range, it functioned fine and appeared to be normal for about 100 rounds until fired one round that resulted in gas exiting the pistol - enough to feel heat and pressure on my hand, but with no damage to the FN Hi Power I was shooting it in.   I recovered and examined the case and discovered this:



I stopped using ammo from those boxes, but when I policed my brass at the end of the session, I discovered 4 more cases that looked just like it.

This was factory ammo in new brass and the failures occurred in portions of the case that were not affected by any corrosion.  

What's left here for probable causes is the excessive tumbling done to clean the ammo up.  In this case, 48 hours of tumbling resulted in about 5% of the ammo having enough pressure to cause the case to fail at the unsupported section of the feed ramp.  I have no idea what powder was used in the ammo, but it apparently did not hold up well to that amount of tumbling.

Personally, I don't tumble live ammo anymore, based on my experience, rather than what I read on the internet.

If I were to tumble ammo for some reason in the future I'd limit it to just a couple hours at most.

I did tumble loaded ammo in rotary tumbler with walnut but now use Lyman vib with walnut. Never had a problem.

Same here. Tumbled 3 loads this week in my 18 pound HF tumbler. 3-500 rounds at a time. Never had an issue.

I tumble live ammo when I finish loading it, and when I have collected a sufficient amount of it from rolling around in my trunk.  Even then, an hour or less is typically required.

If you are considering tumbling loaded rounds, then do this little experiment.  

Prepare your vibratory tumbler and fill it with media.  Start the tumbler keeping the lid off so you can see the contents.

Drop a few rounds (or many) into the moving media.

Watch how the rounds move compared to how the media moves.



What you will see is the ammunition moving very, very slowly.  Rounds may touch each other but they are moving so slowly, having the rounds rub over each other is just not a problem.

The media moves over the surface of the relatively motionless ammo.  As it does so, it will be wiping the lube off the ammo.

I think most concerns were for rotary, dry media, tumblers where the FMJ tips might ignite a primer. I use to hand wipe rounds with paper towel to remove lube but it still left lube residue under the rim that would pull in any media dust and clog up shell plate on 550B after about 300 rounds (have since cut my lanolin-alcohol mix to 1:12).

I tumble loaded .223 loads to the case lube for about 15 minutes. Never had a problem. I have read that some factories and commercial reloaders tumble loaded rounds for the high shine finish.

Sir, yes normally I would not spend money on ammo that is damaged or tarnished enough to need tumbling.  However, a few years ago a friend passed away and the family was trying to sort out all of the things he left behind.  He had a stock of ammo, mostly GI/CMP issue including lot of carbine, .308 ball and M852.  His storage area was a shed behind his house and some of the 308 ball had suffered water damage.  Some cartridges were in loose piles and the brown cardboard boxes  appeared to have melted around them.  I paid the widow for most of it including the M852 which was in excellent condition.  I felt it was the right thing to do for her.  I spend a fair amount of time trying to clean up the water damaged cartridges in corn cob media.  Some cleaned up well but all retained the stain of verdigris.  I still have some of it and have never had a problem with any of it in my M1As.

That said, since most of the rifle cartridges I reload use Sierra MK bullets which as you know are hollow point boat tails, I've avoided ever tumbling them.  I've noticed the media gets jammed into the hollow cavity of the bullet tip and seems to have an adverse affect on the precision and POI.  For this reason I do not tumble my match cartridges.

I don't have any particular concern regarding the deterioration of powder subjected to tumbling and I agree that transportation in the back of my truck probably produces many of the same effects as tumbling.  Except for the instance I've noted above I've never felt there was a need to tumble loaded cartridges.  And yes I've spoken with Ed Emary of Hornady at the Natiional Matches a few times,  He's a wealth of info and a real nice person to boot!  If removal of case lube is a real concern, I suggest simply using carbide dies.  JMHO, 7zero1.

Thank you Gentleman for such a good report and answers. Every once in awhile I have dicovered a loaded round in my vibrator cleaner and wondered if it changed the properties of the powder. You have put my mind at ease and their is a little cup on my bench with some loaded rounds that I feel will be safe to shoot.

I would have to disagree with your belief that the only possible cause for the failure was tumbling. I think you are overlooking the possibility of the brass having structural weakness around the case head.

Have you fired any other ammo from this lot, not effected by the water damage?

DakotaFAL, if you stopped using the ammo, you should have some left.  Disassemble the rounds and check the condition of the powder.  

As an alternative theory, and building on what Flamethrower said, the amount of corrosion products after just a few days suggests to me that galvanic corrosion was at work,... BIG TIME.  

Remember, the cases are brass and, on their own, will resist salt water corrosion fairly well for a long time.  Galvanic corrosion, especially in salt water, can damage anything in no time flat.  Wet paper will not stop the corrosion, as it is not much impediment to the flow of ions through the salt water.  The zinc in the brass is particularly at risk and could be leeched out, weakening the case.  

You could take it one more step forward also. Load the powder and bullet into known good brass and see if it fails the same way.

I agree with the corrosion opinions. But reusing the same components will prove or disprove it.