Us engineers do occasionally do some very silly things but "messing around with live ammo" is not on my to do list, if it was I have a feeling the next item would be "Die". Accidents involving ammo usually end in only one way. BAE had a fatality in an ammo plant in the UK last year, and this year to date we have had 3 safety inspections with more on the way!!!!

Ooohhh a coffe mug! I'm in!

If you continue to be a good source of info I might even be able to get you some stickers!!!!!!!! (The type you stick on things, not what we have been discussing) ;)

Eh, ok. But cool coffe mugs are what I really want.

Arty, My father was an ordnance repairman during the Korean war. Their cure for a sticker was to let the tube sit for 2 hours, then hook a chain to the breech handle. They used a vehicle to pull the chain and open the breech. Clearing the round out of the tube depended on what type of round they had loaded, and how far the round had progressed up the barrel.

From Dad's comments when I asked him about this, he made it sound like it was a fairly common occurrence, mainly caused by bad/inappropriately spec'd ammo left over from WW2.

I just quickly read through this, and am I right in thinking you are talking about a shell being fired, but for whatever reason the shell sticking in the barrel, leaving the hot gasses from the propellant stuck in the chamber, resulting in high pressure? I would have thought the pressure would die down almost straight away, regardless of being confined? I didn't realise an explosion could retain its pressure like that... Could this same thing also happen to a small arm? If I were to fire an L85A2, and there was sufficient dirt in the barrel to jam the bullet prior to reaching the gas plug, would that in effect be a sticker? And more obviously common sense, I assume if the round were to jam after the gas plug, allowing gas to cycle the action, all remaining gas would vent out of the chamber rather unpleasingly? Thats enough to make you paranoid. I will certainly not let my face anywhere near the ejection port next time I open it to inspect for a stoppage!

I'd been pondering the post sticking gas pressure. Since the breech seal is design to withstand much larger pressures I'd guess veting there would be very slow. Arty Engineer might know the details there. This leaves the driving band seal. If the sticker occured because of a improperly sealed driving band then the gas is going to vent quickly past it. It may have vented largely before the projectile stopped moving in the tube. If there was a incomplete burn, or a oversized driving band then the seal between the tube will retain the gas for a indefinite time.

The possible remaining chamber pressures were why they opened the breech from a distance (chain on the breech handle with the other end on a vehicle) Most of the failures my dad was telling me about were due to ammunition, either loading improper ammunition in the tube (easy to do with the proliferation of specs during WW2), or ammunition that should have been destroyed as it was aged.

Are you refering to the soft metal rotating band around the lower one-third of the projo?