How long until a misfired cartridge is safe

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Re: How long until a misfired cartridge is safe

Post by Shotfox » 18 Jun 2014, 10:14 am

Yep well said Warrigul.
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Re: How long until a misfired cartridge is safe

Post by Apollo » 18 Jun 2014, 10:55 am

The general practise after a "misfire" is do nothing for at least 30 seconds keeping the firearm pointed down range. After 60 seconds it should be safe to cycle the action and remove the misfired round for examination.

Misfires can happen with "factory" ammunition and very unlikely it is a problem with the actual ammunition unless somehow it has been damaged, extremely old and/or contaminated in some way like water intrusion.

Most likely misfires happen with reloaded ammunition through some reloading error.

One should always be aware of a "Hangfire" where for some reason the actual primer has fired and the powder has not ignited properly. The powder could be contaminated like with moisture and may possibly actually be burning slowly or start burning slowly then fully ignite so hence the delay in opening the action of the firearm. You certainly don't want the cartridge to ignite with the action partly or fully open. If in any doubt wait, if at a Range then ask for help from the Range Officer if you are unsure of the safety proceedures.

With a new firearm misfires can happen and there is usually a reason. One such instance I experienced was with a brand new Sako causing light firing pin strikes on primers and the cause was excessive grease in the bolt around the firing pin and spring. Where this happened is anyone's guess but once cleaned out and lightly oiled it never happened again.

Other reasons for a misfire with reloaded ammunition can generally be put down to operator error and very seldom a faulty component like a primer.

Primers seated using a reloading press or agressive force with a hand primer tool can cause the primer cup to be crushed or forced against the primer anvil thus not allowing the firing pin strike to ignite the primer substrate. The primer substrate can be cracked / damaged and again will cause it not to function irrespective of how many attempts are made to fire it.

Primers not seated far enough may or may not ignite as the firing pin will most likely just push the primer further into the primer pocket and not cause enough force to impact the primer substrate against the primer anvil to cause ignition. They will most likely show a light firing pin strike to even a normal looking strike but has damaged the primer substrate / anvil.

Thick and / or hard primers and a light firing pin strike. Perhaps from a weak firing pin spring.

The ideal tool to use seating primers is one of the hand primer tools where the seating of the primer against the bottom of the primer pocket can be felt and are less likely to cause primer cup damage but still possible with very soft primer cups like are Federal Small Rifle Primers. Whatever tool is used it should not leave a mark on the primer cup, if it does you are using too much force or perhaps the primer pocket is faulty in some way. Typically here are those that have had their primer crimped in place, usually military type ammunition, and the operator has not removed the crimp after depriming so if a new primer is being seated it will most likely damage the primer trying to get it past the crimp. There are many tools designed to remove factory primer crimps.

At no time should excessive force be used to seat a primer, there is something wrong and should be corrected.

Dirty primer pockets from the residue of previously fired primers should not generally cause any problems but for the sake of consistant seating it should be removed.

Uniform primer pocket depth is ideal and there are many tools designed to achieve this. One such tool is the K&M Primer Pocket Correction Tool and there is one for each type of primer pocket. They are indexed against the cartridge case head to cut to a specific even depth by industry standards. They do not cut or affect the sides / size of the primer pocket. Small rifle / pistol / large pistol primer pockets should be 0.122" and Large rifle primer pockets should be 0.131" in depth. Always seat a primer to touch the bottom of the primer pocket.

One practise I do priming cases is to turn them all primer upwards in my reloading block so you can check that all cases have been primed that you intend to reload and gives you a chance to visually check that all primers are seated the same and below the cartridge case head, not flush but below.

Here is what the correction tool looks like....

Image

Should you have a misfire and need to replace a failed primer then treat it with care. Disassemble the loaded round by removing the bullet and powder. Attempt to fire just the live primer even in another firearm if available but if that fails then there is little choice remaining but to either scrap the entire case safely or remove the live primer. This can be quite dangerous. Against popular belief it is not possible to "kill" a live primer easily by any number of suggested ways like soaking it in water, WD40 or any light / heavy oil. Primer substrates have some form of protective coating or foil to seal them against contamination. Hence why they are not supplied in sealed packaging. Many, many years ago they were not manufactured the same and were more likely to be contaminated.

Your choice but if you decide to remove a live primer then take extreme care. Many say they have done many without a hitch but the potential is there. My suggestion is that it is attempted outdoors, wear safety glasses and hearing protection plus heavy leather gloves (welding gloves or the like), keep you head, body and hands away from the case mouth especially. Proceed very smoothly and slowly and dispose of the damaged, live primer safely.

Not only is a misfired cartridge dangerous but all aspects of reloading can be dangerous so always think safety.

If in any doubt then consult someone with experience.

BTW.... Firing just a primer in a chambered case will sound much like firing a sub velocity rimfire cartridge. It will leave the bore coated in black soot which should be cleaned out afterwards.

Sorry for the long winded post but it is all about explaining a little more about the possible causes of a "misfire" .......

Happy reloading.
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Re: How long until a misfired cartridge is safe

Post by Lorgar » 18 Jun 2014, 7:21 pm

Warrigul wrote:Any of the 308 based cartridges (.308, .243, .7/08 etc) will fit in a .30/06 based chamber(25/06, .270 spring to mind) and fire, especially if the action is mauser based and the extractor holds the cartridge head. It won't fire every time but imagine the issues you may have if a .308 was loaded into a .25/06?


Between having a .243, 7mm-08 and .308 at the same time, and necking .308 brass down to 7mm I can tell you I had to really pay attention to keep things orderly.

Quite easy to mix things up when they're tip down in ammo boxes. Especially for the resized 7mm-08 brass which is stamped .308 on the bottom. I had picked up the incorrect round a few times... Always caught it fortunately.

.243 will obviously chamber smoothly in either of the larger two. And 7mm-08 in the .308.

More worrying (I've never tried this) is I suspect a lot of people wouldn't notice if they loaded a .308 cartridge into a 7mm-08 chamber. Thin neck after a few reloads maybe, if the round was seated back enough not to tough the lands or a shooter was willing to overlook a stiff bolt closure... Disaster...
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Re: How long until a misfired cartridge is safe

Post by Chronos » 18 Jun 2014, 8:41 pm

Lorgar wrote:
Warrigul wrote:Any of the 308 based cartridges (.308, .243, .7/08 etc) will fit in a .30/06 based chamber(25/06, .270 spring to mind) and fire, especially if the action is mauser based and the extractor holds the cartridge head. It won't fire every time but imagine the issues you may have if a .308 was loaded into a .25/06?


Between having a .243, 7mm-08 and .308 at the same time, and necking .308 brass down to 7mm I can tell you I had to really pay attention to keep things orderly.

Quite easy to mix things up when they're tip down in ammo boxes. Especially for the resized 7mm-08 brass which is stamped .308 on the bottom. I had picked up the incorrect round a few times... Always caught it fortunately.

.243 will obviously chamber smoothly in either of the larger two. And 7mm-08 in the .308.

More worrying (I've never tried this) is I suspect a lot of people wouldn't notice if they loaded a .308 cartridge into a 7mm-08 chamber. Thin neck after a few reloads maybe, if the round was seated back enough not to tough the lands or a shooter was willing to overlook a stiff bolt closure... Disaster...


that goes back to what i was saying earlier, when a cartridge is made from another similar one IN GENERAL (that means there may be exceptions) you will not be able to chamber the larger caliber cartridge in the smaller one. yes a .243 will chamber and fire in a .308 but a .308 WILL NOT chamber in a .243, the bullet/neck dimension is larger and will jam in the lands long before the bolt closes.

Like a said manufacturers are aware of this which is why they deliberately DO NOT make the larger caliber cartridge significantly shorter than the smaller one where a parent case is shared

no one in their right mind would mistake a .308 cartridge for a .270. yes it may be possible to chamber it and even fire it (maybe) but the error should be apparent as it was in Warriguls example of the 20g in a 12g.

the real danger in my mind is when you have two calibers so close an error could be made when reloading. take the 7mm and the .270 for example. i reload for 7-08 and .284 so i have a selection of 7mm bullets here. with that in mind i would never reload for a .270 here. it might be possible to accidentally seat a 7mm bullet in a .270 case with potentially disastrous results.

sorry for being so off topic but it's something reloaders should think about.

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Re: How long until a misfired cartridge is safe

Post by Warrigul » 18 Jun 2014, 9:50 pm

Chronos wrote:that goes back to what i was saying earlier, when a cartridge is made from another similar one IN GENERAL (that means there may be exceptions) you will not be able to chamber the larger caliber cartridge in the smaller one. yes a .243 will chamber and fire in a .308 but a .308 WILL NOT chamber in a .243, the bullet/neck dimension is larger and will jam in the lands long before the bolt closes.

Like a said manufacturers are aware of this which is why they deliberately DO NOT make the larger caliber cartridge significantly shorter than the smaller one where a parent case is shared

no one in their right mind would mistake a .308 cartridge for a .270. yes it may be possible to chamber it and even fire it (maybe) but the error should be apparent as it was in Warriguls example of the 20g in a 12g.

the real danger in my mind is when you have two calibers so close an error could be made when reloading. take the 7mm and the .270 for example. i reload for 7-08 and .284 so i have a selection of 7mm bullets here. with that in mind i would never reload for a .270 here. it might be possible to accidentally seat a 7mm bullet in a .270 case with potentially disastrous results.

sorry for being so off topic but it's something reloaders should think about.

Chronos


The are no ifs buts or maybes, it does happen, I have seen an example of a totally wrong calibre loaded in a rifle and this issue is well documented as having caused blown up rifles in the past.

Don't confuse by seeding doubt unless you have something legitimate to add.
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Re: How long until a misfired cartridge is safe

Post by Farmjer » 23 Jun 2014, 6:46 pm

rummer wrote:.243 is the same as .308 except for the neck right? So you could smoothly load a .243 round into a .308 without noticing and fire it?

Nothing to stop you firing it?


Correct. The rest of the case dimensions are the same, nothing in the way from pin to primer.
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