Tumbleing loaded ammo ???

[Mark Phillips]

I have ben reloading for the past 45 years, and have always tumbled loaded ammo, I recently started precision rifle shooting, and notice that un tumbled .308 rounds had a more consistant velocity than my tumbled rounds, I had a SD of 12 FPS on the un tumbled ammo and 70 FPS SD on the Tumbled rounds. Has anyone else noticed this?

 

[Broz]

Had the tumbled rounds been loaded for a longer time?

Jeff

 

[Bravo 4]

I remember tumbling loaded ammo being discussed a while back:
http://www.longrangehunting.com/forums/f28/tumbling-loaded-ammo-84781/


If I want to polish some loaded ammo I use a Lee zip trim and some green scotchbrite pads, takes a few seconds per case.

 

[gohring3006]

Maybe small changes in oal. Did you check the oal before and after?

 

[BountyHunter]

My question is why even do it?

 

[acloco]

Powder can be breaking down when tumbling, both physically and chemically.

 

[LoneTraveler]

I do not tumble loaded ammo. What I wonder about is breaking down of powder and WHAT ABOUT THE PRIMER COMPOUND? If the powder breaks down into small pieces, These pieces can migrate through the flash hole and fill the space under the primer, and make a bigger flame come out into the powder when the primer fires making inconsistent velocity on each shot. If the primer compound breaks into dust and small pieces of the primer migrates through the flash hole into the powder charge could cause less primer fire into powder and different velocity. Many Bench Rest shooters weigh the primers for consistency. Then after vibrating the primers in the shell It would be a SWAG as to what each primer weight would be now.
This would make for an interesting experiment.

 

[Greyfox]

I would be hesitant to do this. It is very possible that the tumbling action on the powder granuals could effect the shape/size and therefore the powder density in the loaded case. Additionally, changing the polish/surface characteristics of the bullet surface/meplat, or dust entering the hollow point on target bullets is a question as well. IMO.

 

[Laelkhunter]

My question is, what is the reason you are tumbling after you have loaded the ammo? Is it for the polished look? I tumble my brass after sizing and trimming, and before priming (making sure the flash hole is clear of any grit), and they look better than new after they are loaded. I can't think of any reason to tumble loaded rounds that would outweigh the negatives that have been discussed here.
I would be worried about a possible detonation, damaging the meplat of the bullet, degrading the consistency of the powder, or possibly affecting the primer some type of way.

 

[blkdog]

Please check with the powder mfr. They warn against it due to the fact that it breaks down the coating on the powder and can result in unpredictable results as you are seeing in your loads.

 

[Deleted member 46119]

Please check with the powder mfr. They warn against it due to the fact that it breaks down the coating on the powder and can result in unpredictable results as you are seeing in your loads.

What he said!

No need to tumble loaded rounds.
Tumbling loaded rounds will damage meplats and induce run out.
There are powder issues.

If you have sizing lube on the cases, I would just wipe them off.

 

[SidecarFlip]

All well and good and to each, his own, but lets throw this into the mix shall we....

The propellant itself comes packaged in 1 pound or 8 pound containers, none are completely full...

So, from the time the propellant is manufactured, to the time it's packaged, to actual shipment to the store or you via some shipper (usually UPS), that propellant is being sloshed around in the container, sometimes abruptly (if the UPS employees are playing catch with your package)....

So the propellant granules are rubbing against each other anyway...

And the pills and the brass, same scenario...

I don't see that tumbling for a short time after reloading makes one iota of difference in as much as the components get jostled and banged around way more than a few minures in a tumbler would do.

I tumble all of mine (after loading for 5 minutes) to remove the sizing compound, always have and will continue to do so.

I see no change in groups or velocity. I do see less chamber and receiver fouling.

 

[SidecarFlip]

Please check with the powder mfr. They warn against it due to the fact that it breaks down the coating on the powder and can result in unpredictable results as you are seeing in your loads.

Sure about that? Have a link to substantiate?

 

[BergerBoy]

I do not tumble loaded ammo. What I wonder about is breaking down of powder and WHAT ABOUT THE PRIMER COMPOUND? If the powder breaks down into small pieces, These pieces can migrate through the flash hole and fill the space under the primer, and make a bigger flame come out into the powder when the primer fires making inconsistent velocity on each shot. If the primer compound breaks into dust and small pieces of the primer migrates through the flash hole into the powder charge could cause less primer fire into powder and different velocity. Many Bench Rest shooters weigh the primers for consistency. Then after vibrating the primers in the shell It would be a SWAG as to what each primer weight would be now.
This would make for an interesting experiment.

I was always told this by my father. - the brake-down of powder and primers.