Tumbler question

I know it's a personal choice, but for me, I wouldn't. Reason being is I load for accuracy, and tumbling loaded ammo can further bump the bullets slightly out of alignment - yes, I even pack my ammo boxes so they don't get bumped around. The value on a great shot, versus a sparkly clean cartridge is worth more to me.

 

Don't tumble live rounds. If you want them to shine, use Flitz and a rag.

 

Don't tumble loaded brass

 

Lots of people say don't tumble it. Lots of people do it. There are very few actual cases of problems (google it).

Big problem with trying to tumble loaded brass is the weight. They sink to the bottom and does not work well in my experience using anything heavy in a vibratory tumbler.

 

The only reason you shouldn't tumble loaded brass is that "everyone on the Internet says no!"

I've tumbled it for years and haven't had any sudden explosions, broken rifles, etc. Some have even heard this admonishment so long they've run their own tests. Tumbled loaded ammo for 24 hours or more, disassembled it, and examined powder for any signs of breakdown, powdering, etc.

It's am matter of choice but a 10 minute trip through the vibrator in corncob will take all the lube off with no damage.

You can believe those who are merely parroting what they heard or read on the net or you can believe those that have done it for years (over 30 for me) without incident.

Give it some thought. Did all those GI's in Vietnam, Iraq, Afghanistan, receive ammo that WASN"T subjected to hours and hours of vibration? From the plane that took it to the country, the C-130 that took it to the Bases, and the helicopters that then transported it to the FOB's, there was more vibration and rough handling of that ammo than if you left it in your "tumbler" filled with ground corn cob for a week. Hell, even if it wasn't transported to an FOB by chopper, ever rode in the back of a military truck?

 

Vibrating live rounds will often change your velocity, depending on powder. Intense vibration abrades the retardant coating and sometimes breaks up the structure.

For hunting or plinking rounds it isn't enough to matter. If you are shooting for extreme precision I wouldn't do it.

 

That very statement has been "debunked" many times. Again, some have tumbled rounds for as many as 24 hours, shot over a chronograph, compared with untumbled rounds, and found NO variations. I personally have done this with .223 and 9mm. The only variations I got were well within the normal SD/ES that one experiences with untumbled rounds. These variances were well within what one could expect in just ordinary changes in temperature from day to day.

Let's once again consider some facts. Just exactly how much room is there in an average finished cartridge. Most standard loads exceed 90% of the available space so there's not much room for the granules to move around. Kind of like a full bus versus an empty one. The full one cushions all the standing passengers while the empty one can allow the single standing passenger to be tossed about.

Next, one of those "coatings" is graphite. It's there to act as a lubricant, as well as it's retardant qualities, so the powder will flow freely while being dispensed in loading machines.

In short, if one doesn't want to tumble loaded ammo, then DON'T. Please don't perpetuate the all too frequent "Internet Myth".


PS: I know that there are all kinds of admonitions against tumbling loaded ammo from makers of tumbling machines. They have lawyers that tell them to do so. Just remember though that EVERY maker of a firearm makes a similar admonition about "never shooting reloads".

 

I'm sorry, but I disagree. I have done my own test and have found a statistically significant difference. Admittedly this was with older stick powders and nothing "new".

The difference may also be partially due to creating space in the case.

AFAIK, the retardant is not graphite, but graphite is also added for the reason you mentioned.

 

Did you take into consideration how most chronographs actually measure speed? Are you aware that a more "reflective" bullet can yield a different speed reading than one that is less reflective (dull).

In order to get consistent readings between polished bullets and those that have been sitting in a box for a while both should be blackened with a sharpie oe such. FWIW, even a slight difference in setting up the chronograph, level of the sensors, distance to muzzle, and lighting conditions from session to session can yield variations.

All that aside, as I stated earlier, if you don't want to, don't. Far too many people have "debunked" the myth that tumbling ammo degrades the powder. Even to the point of disassembling cartridges after tumbling and examining the powder for the presence of "fines" that were ground off the granules. Not just by "looking at it" but actually using a pocket optical comparator which is essentially a small measuring microscope.