No, that article says "Extensive tumbling can cause the breakdown of the powder grains". Define extensive? Hours, days, weeks? You need 10min to remove the lube. That article also doesn't quote any non-lab cases of powder breakdown.

 

Put a factory box of ammo on a train across the country and it will get significant shacking for many many hours. Or on a plane on a 12h flight, etc.

 

I'm sure it's an obligatory disclaimer, just like "don't shoot reloads or lead bullets in your Glock." Factories shine up ammo before the final packaging, but it's only for a few minutes. So, it seems to not be a problem. But I don't see it as an optional step in any A-B-C reloading manual yet. And if planes, trains and trucks jostled goods so much, we'd never get an egg delivered to the supermarket.

The only way the grains would break would be crashing into each other, (nothing else within case is moving, right?)...so if that was a legitimate risk you'd think the same damage would happen in the powder jug while its being transported, maybe even moreso since there's more weight pressing down in a full jug. And if you run a full or compressed charge they can't move in a case at all!

 

That being said, I don't do it but I know plenty of people who tumble complete rounds and have had no issues. Personally I put a pretty light crimp on my stuff that I'd be more concerned a bullet will vibrate a few thousandths further in or out of the casing.

Excerpt from the article I provided from Accurate Shooter in my link above:

 

Hodgdon’s official policy is: “Completed ammo should not be tumbled. The powder will degrade and increase in burn speed.” (From Mike Daly, Customer Satisfaction Manager, Hodgdon/IMR.)

 

Of course their Official policy is that..it's driven by Liability..just like pretty much every single Firearm out there has some kind of verbiage in the manual about how you should never ever shoot antyhing but "Factory Ammunition in good Condition" out of their guns, or even a Warranty Disclaimer if you are shooting reloads.

Russian roulette x 200.

Interesting. Found this thread looking for folks who have tumbled the surplus garand stuff.

Just got a shipment from Orion and the shipping box was pretty bet up. Have no doubt that the ammo was bounced around a bit too.

What surprised me was how dirty the stuff was. So I was thinking why not tumble this for a bit to clean it up and make it look nice, hence finding this thread.

 

After watching the SAMMI video of the burning ammo, in which they include a 65' drop test and shooting rifle rounds through boxes of ammo, I am thinking a little tumble to clean this stuff up is in order and will be ordering my tumbler.

 

 

Tumbling loaded rounds can potentially alter the powder in the case, and is dangerous. Changing its physical characteristics could potentially change the burn rate.

 

 

Don't see how that can happen, and the AR15 post tends to confirm the powder is unchanged.

 

It doesn't seem like a stretch that a bullet tip or rim might get accidentally slammed into the primer of a loaded bullet. It is why lever guns with tube magazines recommend you use flat point bullets.

 

It is a bit of a stretch to think tips could strike the primer hard enough to set one off. And again, the SAMMI video shows there is no propagation of rounds going off with an errant strike firing off a primer.