Beating gunpowder to death while inside a cartridge?

[Howdy Schutem]

   Hopefully I'm in the correct forum for this subject. And please forgive me if this topic has been covered before.  My feeble eyeballs have not spotted a previous discussion.
   A current cowboy action shooter friend of mine, also a retired police officer, as well as a guy who, like me, spends a fair amount of time with his family bashing along very, very rough Colorado 4WD off-road routes visiting remote mountain mining ghost towns and creeping along abandoned railroad grades.Then hitting about 70 m.p.h. with the CJ 7 Jeep for several hours on Sunday driving back home via paved highways.
   He states that the gunpowder in the interior of shotgun shells, rifle or handgun cartridges, in fact anything containing gunpowder, eventually grinds against itself while bouncing around in a vehicle, and the grinding action will eventually effect and lessen performance. He said he heard about it from a long-time officer who was about to retire just as my friend was starting with a big city force several decades back. So he changes ammo in the firearms he hauls along on the mountain outings after every trip. I realize he's not doing any harm, and he's probably out-smarting me!
   I rotate my ammo maybe every 6 weeks or so and use the rounds I've been carrying in the holster or in a vehicle for target practice. It's a habit I picked up years ago. But I've been curious about my friend's statements.
   Can you really beat ammo, or actually it's powder, to death by vehicle bounce? It seem's like it would take a very long time.
   Thanks in advance.

[Graybeard]

I think it would take more than a bouncing vehicle to do much damage to the powder and that is assuming there is air space in the case so it can actually move around and grind against other powder grains. But if what you mention does happen it would make the grains smaller which would increase the burn rate and if anything raise pressures and make the bullets faster not slower. Removing the deterrent coatings would do the same.

[jhm]

what is rougher a 4x4 or a running horse or one pulling a wagon.   JIM

[Brett]

Gun powder granules are so light I doubt that they would do much grinding of each other in something as small as a loaded cartridge or shot shell.   I would be more concerned about the effects of heat and moisture than rough handling. 

Howdy, how often do you encounter squibs when you shoot the ammo you have rotated out of service?  My guess... very few. Probably no more than you would get with fresh ammo.   

[powderman]

It would take a awful lot of shaking to alter the gunpowder in a ctg. In a shotgum pretty well impossible, it is compressed by the wad. There would have to be a considerable amt of air space in a loaded ctg, and a whole lotta shaking to do what your friend has said. POWDERMAN. 

[beemanbeme]

How much time does the powder spend via plane, train, and truck before it ever gets to you and a can of 4350 still looks like 4350.  Your imported powders, from Sweden and Oz, would be even more shaken.  They look the same. The other day, I took out some hunting ammo I loaded 16 years ago.  It hadn't been constantly jolted around but it had made two or three (at least) trips to and thru and around the Big Horns in Wy.  It printed 1" high at 100 yards just like it did 16 years ago.
I think it's a old wives tale.

[Smokin Joe]

Modern smokeless powder is pretty tough stuff. It's similar in composition to nitrocellulose plastic.

[Howdy Schutem]

  Thanks for all excellent replies so far.
  Even though I'm a long time handoader, I never thought about the coatings on the powder granules. I assume that would make the powder more durable, assuming how much if any type of pounding or grinding takes place inside a brass case in the first place, which I now doubt more than before.
   I cannot remember my last squib load, so it must have been many years back. We are concerned about the heat and cold. We live in the semi-desert section of west-central Colorado, and this summer we had our share of days with 100 degree plus heat. So how much warmer is it inside a vehicle? A lot! I believe you are correct on temperatures effecting ammo much more than any possible jumping and bumping with the powder inside the ammo.
    I never considered all the transportation involved in getting powder from the factory to our local dealers either. Crossing the Atlantic, than going by crane at the dock and then wheeling around inside trucks for who knows who long probably ain't all that gentle.
    Then there are those instances we've all read about, or maybe a few of us have seen first hand; WWII era ammo, or older even cartridges, that fires pretty accuratally without any problem. Some of it is even left-over Army ammo. You know that wasn't handled with kid gloves!
       

[bulzaye]

My Father in law used to tumble all his loads after they were finished. He loaded for high power center fire cartridges as well as handgun. He was told about the problems with the powder breaking down causing higher pressures and ignored it. After he passed away, I inherited all of his reloading equipment and loads he had around. I pulled a lot of them apart due to not being sure what they were for loads. I did not find one that had any powder breakdown or any other problems. He shot them faithfully for years while doing this and never had a problem. I certainly am not recommending this to anyone and I do not myself. Just stating what I saw.

[Almtnman]

Howdy Schutem, if you're worried about the temperature ranges of your loads and load for a rifle, you might want to give Hodgdon Varget a try. It's supposed to be consistent with a wide range of temperatures.

I wouldn't worry too much about the vibration as I think it doesn't vibrate enough in the case to do any damage. I had a reloaded 44 magnum load in my Wrangler pants pocket and it went through the washing machine full cycle. I figured that the powder or primer was wet or wouldn't fire so I put it in my pistol and it fired just as good as any of the other loads.

[Sourdough]

I carry ammo in a bag attatched to the handlebars of my dirt bike (motorcycle) can't get any rougher than that.  Then come winter that bag gets transfered to the handlebars of a snow machine.  Never noticed any differance in the performance of a batch after carrying them around for a year of so.

[powderman]

I carry ammo in a bag attatched to the handlebars of my dirt bike (motorcycle) can't get any rougher than that.  Then come winter that bag gets transfered to the handlebars of a snow machine.  Never noticed any differance in the performance of a batch after carrying them around for a year of so.

If that wouldn't do it nothing would. POWDERMAN.