Archie
Member
A couple of things for reloaders (and shooters in general) to remember.
There are several 'levels' of pressure. The measurements - usually in 'pounds per square inch' (PSI) or something similar like "lead units of pressure" (LUP) or "copper units of pressure" (CUP) - vary depending on firearm, but the 'levels' are there.
The lowest level is 'insufficient pressure'. The result is the bullet doesn't leave the barrel and or the (semi-automatic or automatic) arm doesn't operate properly. This insufficient pressure will not of itself damage the arm, but can cause damage of other sorts. Beating the stuck projectile from the barrel can be damaging. Firing another shot behind a stuck bullet usually causes some problems.
The next level is 'optimal operating pressure'. The bullet launches at the expected and appropriate velocity, the action works properly. This is what is desired and all is well with the world.
One step up is 'over pressure not generating a catastrophic failure'. This is potentially the most misleading level.
The arm can fire seemingly 'normally'. However, the operating pressure is greater than what the mechanism will stand. For instance:
The M1 Garand rifle operating rod will bend IF the remaining pressure in the barrel is above a certain pressure when the bullet passes the operating gas port and allows burning and expanding gas from the gunpowder to enter and operate the arm. Normally, this is caused by the powder being too slow burning and maintaining pressure higher than desired, or too heavy a bullet weight (or both). The pressure in the chamber is within proper limits, so there's no danger of a catastrophic failure, but the rifle can be damaged - either instantly or over time.
Another instance is that of semi-automatic arms suffering 'battering'. The action opens too fast and the moving parts (bolt, slide or connecting rods) batter against each other or against the frame. The arm does not 'blow up', but over time is rendered incapable of firing.
Revolvers can undergo stretching of the frame, usually the top strap above the cylinder. This is normally the cause of fore and aft play in the cylinder. This in turn causes excessive cylinder gap; loss of velocity and 'spitting' from the cylinder gap. (The lead and powder 'spitting' makes one rather unwelcome on the firing line.)
Manually operated arms can have the locking lugs on both bolt and frame deformed. This is called 'battering', 'peening' and 'set back'. Essentially those surfaces which bear the brunt of the cartridge recoil will deform. In most arms, this results in excessive headspace.
This condition is detrimental as it usually isn't noticed immediately. The damage takes time and occurs incrementally. It can eventually result in frame or mechanism failure. Generally, damage to brass is obvious prior to the arm failing. A load in most anything can be 'safe' (not causing a disaster upon firing) but harmful to the arm.
Usually, signs appear on the fired cases. Any load which expands primer pockets is probably damaging the arm to some degree. Any load sticking in the chamber when being withdrawn is suspect. Sometimes there may be other factors, but find out.
If the arm is frozen after firing, one should consider over pressure. A bent operating rod (even if not an M1) should be viewed as a problem sign.
The last level of pressure is catastrophic failure. This is the classic 'trigger actuated hand grenade' effect. The arm physically breaks apart. People on the range stare at one and ask questions like "What was that?" Perhaps they say things like "Why did you throw that bit of bolt handle at me?"
Very quickly, there are two forms of catastrophic failure. A burst barrel - especially toward the muzzle - is indicative of a plugged barrel. Something has jammed the bore shut and the cartridge is likely not the problem.
A chamber failure, is normally due to the cartridge reaching ultra high pressure too quickly. This can be due to overloading - either too much powder, the wrong powder, or too heavy a bullet - or the prior bullet being stuck in the bore just deep enough to allow the next cartridge to chamber completely.
So how does one avoid this sort of thing?
Pay attention. Read the loading manual (information) and follow the directions.
Pay attention to the powder used (insuring it is the correct powder) and the amount dispensed.
Pay attention to the bullet used. Check for correct weight and check construction. Some bullets have a different internal structure and respond to land engraving differently. Make sure the bullets are the correct diameter - although it's difficult to use bullets of "too improper" caliber.
The 9mm/.357" clan of bullets tend to be most confusing. I've never had a disaster from using .355" to .358" bullets interchangeably. However, I've had problems getting .355" bullets to properly seat and stay in .38 Special or .357 Magnum cases. Also, .357" bullets will sometimes not chamber when seated in 9mm cases. (Not to mention the 'bulge' in the case.)
I've never tried it, but there are bullets of 180 grains made for .35 caliber rifles which might load in .357 Magnum cases. I would not experiment to see if the internal structure is detrimental in any of my revolvers.
Nor would I attempt a .458" diameter 300 grain (rifle) bullet in any of my .45 ACP or .45 Colt handguns.
Main point to remember: Not all overloads will immediately blow up a firearm. But there's usually some damage accruing. Also remember, the internal pressure of cartridges can vary a bit. The first overload may be just under the critical pressure for a catastrophe and the next one just over. Ugly surprise.
There are several 'levels' of pressure. The measurements - usually in 'pounds per square inch' (PSI) or something similar like "lead units of pressure" (LUP) or "copper units of pressure" (CUP) - vary depending on firearm, but the 'levels' are there.
The lowest level is 'insufficient pressure'. The result is the bullet doesn't leave the barrel and or the (semi-automatic or automatic) arm doesn't operate properly. This insufficient pressure will not of itself damage the arm, but can cause damage of other sorts. Beating the stuck projectile from the barrel can be damaging. Firing another shot behind a stuck bullet usually causes some problems.
The next level is 'optimal operating pressure'. The bullet launches at the expected and appropriate velocity, the action works properly. This is what is desired and all is well with the world.
One step up is 'over pressure not generating a catastrophic failure'. This is potentially the most misleading level.
The arm can fire seemingly 'normally'. However, the operating pressure is greater than what the mechanism will stand. For instance:
The M1 Garand rifle operating rod will bend IF the remaining pressure in the barrel is above a certain pressure when the bullet passes the operating gas port and allows burning and expanding gas from the gunpowder to enter and operate the arm. Normally, this is caused by the powder being too slow burning and maintaining pressure higher than desired, or too heavy a bullet weight (or both). The pressure in the chamber is within proper limits, so there's no danger of a catastrophic failure, but the rifle can be damaged - either instantly or over time.
Another instance is that of semi-automatic arms suffering 'battering'. The action opens too fast and the moving parts (bolt, slide or connecting rods) batter against each other or against the frame. The arm does not 'blow up', but over time is rendered incapable of firing.
Revolvers can undergo stretching of the frame, usually the top strap above the cylinder. This is normally the cause of fore and aft play in the cylinder. This in turn causes excessive cylinder gap; loss of velocity and 'spitting' from the cylinder gap. (The lead and powder 'spitting' makes one rather unwelcome on the firing line.)
Manually operated arms can have the locking lugs on both bolt and frame deformed. This is called 'battering', 'peening' and 'set back'. Essentially those surfaces which bear the brunt of the cartridge recoil will deform. In most arms, this results in excessive headspace.
This condition is detrimental as it usually isn't noticed immediately. The damage takes time and occurs incrementally. It can eventually result in frame or mechanism failure. Generally, damage to brass is obvious prior to the arm failing. A load in most anything can be 'safe' (not causing a disaster upon firing) but harmful to the arm.
Usually, signs appear on the fired cases. Any load which expands primer pockets is probably damaging the arm to some degree. Any load sticking in the chamber when being withdrawn is suspect. Sometimes there may be other factors, but find out.
If the arm is frozen after firing, one should consider over pressure. A bent operating rod (even if not an M1) should be viewed as a problem sign.
The last level of pressure is catastrophic failure. This is the classic 'trigger actuated hand grenade' effect. The arm physically breaks apart. People on the range stare at one and ask questions like "What was that?" Perhaps they say things like "Why did you throw that bit of bolt handle at me?"
Very quickly, there are two forms of catastrophic failure. A burst barrel - especially toward the muzzle - is indicative of a plugged barrel. Something has jammed the bore shut and the cartridge is likely not the problem.
A chamber failure, is normally due to the cartridge reaching ultra high pressure too quickly. This can be due to overloading - either too much powder, the wrong powder, or too heavy a bullet - or the prior bullet being stuck in the bore just deep enough to allow the next cartridge to chamber completely.
So how does one avoid this sort of thing?
Pay attention. Read the loading manual (information) and follow the directions.
Pay attention to the powder used (insuring it is the correct powder) and the amount dispensed.
Pay attention to the bullet used. Check for correct weight and check construction. Some bullets have a different internal structure and respond to land engraving differently. Make sure the bullets are the correct diameter - although it's difficult to use bullets of "too improper" caliber.
The 9mm/.357" clan of bullets tend to be most confusing. I've never had a disaster from using .355" to .358" bullets interchangeably. However, I've had problems getting .355" bullets to properly seat and stay in .38 Special or .357 Magnum cases. Also, .357" bullets will sometimes not chamber when seated in 9mm cases. (Not to mention the 'bulge' in the case.)
I've never tried it, but there are bullets of 180 grains made for .35 caliber rifles which might load in .357 Magnum cases. I would not experiment to see if the internal structure is detrimental in any of my revolvers.
Nor would I attempt a .458" diameter 300 grain (rifle) bullet in any of my .45 ACP or .45 Colt handguns.
Main point to remember: Not all overloads will immediately blow up a firearm. But there's usually some damage accruing. Also remember, the internal pressure of cartridges can vary a bit. The first overload may be just under the critical pressure for a catastrophe and the next one just over. Ugly surprise.
