Primer ignition testing

[Davy]

We have just started the primer ignition testing on a new project and today it was time to do the high speed photography both still and moving and I thought this resulting image might be of interest.

 

This is a sequence of four shots taken at exactly the same period into the ignition process using a dummy barrel extending 18,0mm from the end of the cartridge. Chamber was .308 Win, Brass was Federal and the top two primers are a different make to the bottom two. Neither are magnum so it is interesting to see how much brighter the perceived flame is in the lower two images.

 

These were taken at the equivalent of 2800fps with no filtering or post image manipulation. The actual video of each test shows the ignition process slowed down to approximately 7 seconds in time

 

 

Today was not meant to be a scientific test, instead more a reference for the shift from coil spring to Belleville stack ignition however it has raised so many questions that we will go back and film again from two angles in mono and colour and with an extended range of primers and compare the Palma brass at the same time. I must point out this is not going to be a primer bashing test as I use both of these primers myself and have no plans to change them.

 

I have posted the videos of these tests on my Journal if anyone is interested.

[Swamp Donkey]

Interesting pics mate.

[brown dog]

Interesting vids, in the 'watching a firework' ooooh, aaaah sense; but I'm struggling to visualise what you're hoping to deduce?

 

Big visual flash or little visual flash - is there a known correlation with burn temp and velocity? I doubt it. I can't see what you'll get beyond "the CCIs look the same, but different to the Feds (which also look the same)" (and oooooh aaaaah )

[Ronin]

Very interesting David

 

 

There is a bit of info and images on the web of various brands of primers being struck and the burn video'd.

 

This makes things much clearer.

 

 

I had a txt yesterday from a friend who is currently stalking in Scotland, saying he twice suffered from non ignition (light primer strike) in cold weather.

 

Interestingly, the cartridges both fired after being warmed in the pocket for a few minutes.

 

I wonder if you could replicate cold weather (minus 5 ish) and take images of primer ignition in sub zero and plus zero temps....interesting to see the difference.

 

HAsten to add, there was nothing wrong with the rifles firing mech, trigger, bolt spring etc..

[Danpd]

Interesting vids, in the 'watching a firework' ooooh, aaaah sense; but I'm struggling to visualise what you're hoping to deduce?

 

Big visual flash or little visual flash - is there a known correlation with burn temp and velocity? I doubt it. I can't see what you'll get beyond "the CCIs look the same, but different to the Feds (which also look the same)" (and oooooh aaaaah )

 

Pretty much my thoughts also.

[brown dog]

Very interesting David

 

 

There is a bit of info and images on the web of various brands of primers being struck and the burn video'd.

 

This makes things much clearer.

 

 

I had a txt yesterday from a friend who is currently stalking in Scotland, saying he twice suffered from non ignition (light primer strike) in cold weather.

 

Interestingly, the cartridges both fired after being warmed in the pocket for a few minutes.

 

I wonder if you could replicate cold weather (minus 5 ish) and take images of primer ignition in sub zero and plus zero temps....interesting to see the difference.

 

HAsten to add, there was nothing wrong with the rifles firing mech, trigger, bolt spring etc..

 

Hoofbeats, zebras.

 

Light strikes at -5?

That sounds mechanical rather than chemical. I'd be asking what lubricant he has on the firing pin -low temp gumming?

For a field fix, I'd strip the bolt, and dry the firing pin channel, firing pin and spring completely (ie take absolutely all the lubricant off) - and, if needed, grey the firing pin with pencil 'scribble' (ie give it a layer of graphite).

[Davy]

Interesting vids, in the 'watching a firework' ooooh, aaaah sense; but I'm struggling to visualise what you're hoping to deduce?

 

Deduce? Nothing at this stage, my interest was purely to create a reference for the move from coil spring to Belleville stack and as the camera was to hand we decided to compare primers, the results of which I thought might be of interest to some. Certainly high speed images of primer ignition tests have been done in the past however I had not personally seen the slow motion film of the tests and to see the different primers being fired at exactly the same time in slow motion was interesting to me and will be even more so when we run them in colour, and with a few more primers and Palma brass.

[foxing2night]

Deduce? Nothing at this stage, my interest was purely to create a reference for the move from coil spring to Belleville stack and as the camera was to hand we decided to compare primers, the results of which I thought might be of interest to some. Certainly high speed images of primer ignition tests have been done in the past however I had not personally seen the slow motion film of the tests and to see the different primers being fired at exactly the same time in slow motion was interesting to me and will be even more so when we run them in colour, and with a few more primers and Palma brass.

Keep it coming,,

 

Me personally i would be very interested to learn what the lock times are between the two????

 

Faster the trigger the better in my book,,,,

 

Speak soon, Darrel

[Davy]

Hey Darrel, how is the foxing going?

 

Calculated lock time for the Belleville stack shows it will be around 15%-20% faster.

 

However there are many other advantages as well, such as no loss of energy because the stack is effectively disengaged when the pin is unmale chickened, whereas a conventional coil spring looses energy in the first 24 hours after manufacture as the spring relaxes from it's original state and then continues to loose energy even if unmale chickened as the spring is still partly compressed unless completely would off. The firing pin is considerably lighter with the stack as it is so much shorter, typically 30,0mm or less and the spring energy when released is explosive as opposed to progressive so you get a very fast strike that is consistent time after time after time and of course if you want to tune it just add or remove a couple of disks (Never remove just one as a stack should always have an odd number of disks in it)

[Chris-NZ]

Davy

 

I once got a prof Mech Eng mate to do some modelling on behalf of my clubmates (Tony Halberg and John Hastie) who were making HHE- Millennium actions at the time. This is the later improved model of my RPA CG-2000. Anyway, Tony wanted to know the lock time of this action which is driven by a Belleville stack.

 

I can't recall what calculation process he used but based on the c*cked force/mass/other variables, the calculated lock time was about 1.1msec from memory. Pretty fast anyway

 

Chris-NZ

[Davy]

Chris,

 

I am quite a fan of the Millie action and was disappointed when production ended, my understanding is it was beyond the control of Tony and John at the time and was entirely down to the engineering shop they used coming under new management.

 

Your RPA CG 2000 was designed by Robert Chombart (Robert turned 81 yesterday) The action I am working on is Roberts design and I was with him Tuesday when he spoke of HHE with great fondness and still rates the Millennium very highly.

 

Am I correct to think John passed away earlier this year?

[Ronin]

BD, could be gumming,

 

 

but the bolt wasn't touched, the offending round was removed from the breach in both instances and placed in pocket to warm for five mins.

 

 

Rifle and bolt left in ambient temp.

 

Both rounds fired after five mins warming..

 

IMO, gumming would still be present if temp was affecting the mainspring and pin mech.

 

I'll have further discussion with rifle owner tomorrow, I hope he drops in for tea and biscuits as he is passing on return journey.

[brown dog]

BD, could be gumming,

 

 

but the bolt wasn't touched, the offending round was removed from the breach in both instances and placed in pocket to warm for five mins.

 

 

Rifle and bolt left in ambient temp.

 

Both rounds fired after five mins warming..

 

IMO, gumming would still be present if temp was affecting the mainspring and pin mech.

 

I'll have further discussion with rifle owner tomorrow, I hope he drops in for tea and biscuits as he is passing on return journey.

 

I take your point, but I suspect there's more going on here than meets the eye; I'd be pretty stunned if -5degC had an effect on a primer's ability to light; I'd also be pretty surprised if it had am empirically measurable effect on its burn rate vs, say +5degC. Granted this wasn't (I assume) a military primer, but rifles function at much colder temps (eg standard commercial ammo for protection from polar bears).

The words 'light strike' need scrutiny; does he mean a shallower impression on the primer (this wasn't a Blaser firing reloads was it?! )?

I think the 'warming in the pocket' thing is coincidental - unless his firing pin protrusion is set very short, his chamber is at the long end of saami and his ammo is at the short end of sammi; but again I'd be thinking mechanical rather than chemical.

In addition to suspecting gumming, I'd also suspect frozen condensation in the mechanical firing chain; cleared on the failure to fire then 'all good' for the second attempt. Had he allowed the rifle to warm at any point in the day? (eg getting into a heated vehicle to change location, having his piece near a fire, either'll put condensation in the rifle that'll freeze when he goes back out).

But we're starting to get into arctic warfare weapon handling - and -5 isn't really that cold; my money is on a 'perfect storm' of minor mechanical factors: a bit of gumming, a bit of frozen condensation; short pin protrusion, long chamber, short ammo all adding at -5 to tip him over a 'light strike' precipice.

-5 just isn't extreme enough to be stopping primer comp from working.

[gbal]

I take your point, but I suspect there's more going on here than meets the eye; I'd be pretty stunned if -5degC had an effect on a primer's ability to light; I'd also be pretty surprised if it had am empirically measurable effect on its burn rate vs, say +5degC. Granted this wasn't (I assume) a military primer, but rifles function at much colder temps (eg standard commercial ammo for protection from polar bears).

The words 'light strike' need scrutiny; does he mean a shallower impression on the primer (this wasn't a Blaser firing reloads was it?! )?

I think the 'warming in the pocket' thing is coincidental - unless his firing pin protrusion is set very short, his chamber is at the long end of saami and his ammo is at the short end of sammi; but again I'd be thinking mechanical rather than chemical.

In addition to suspecting gumming, I'd also suspect frozen condensation in the mechanical firing chain; cleared on the failure to fire then 'all good' for the second attempt. Had he allowed the rifle to warm at any point in the day? (eg getting into a heated vehicle to change location, having his piece near a fire, either'll put condensation in the rifle that'll freeze when he goes back out).

But we're starting to get into arctic warfare weapon handling - and -5 isn't really that cold; my money is on a 'perfect storm' of minor mechanical factors: a bit of gumming, a bit of frozen condensation; short pin protrusion, long chamber, short ammo all adding at -5 to tip him over a 'light strike' precipice.

-5 just isn't extreme enough to be stopping primer comp from working.

Re -5,and BD-such coolness hasn't been much of a reported problem for primers in N N America,or Scandinavia- (or Scotland this weekend!)....

george

[terryh]

Davy

 

Interesting to see if different mechanical devices give diffent results. Will the Belleville stack be any more effiicient though? You can definitly get more 'energy' into a shorter coulumn but what does this mean mechanically, actually on the line? If you produce greater effort in a shorter distance you're going to have to compress the springs in a shorter distance = more bolt lift effort = distubed second shot or disturbed rifle in the rests (which is why I believe a certain action is not normally seen as being competative for say F Class?).

 

What I''m more interested in at the moment, coming a little bit off top (but not much) is 6 ignition on a RF? Anyone played with this?

 

Always good to see things being questioned or exhamined - what you do with the redults is also interesting

 

Terry

[gbal]

We have just started the primer ignition testing on a new project and today it was time to do the high speed photography both still and moving and I thought this resulting image might be of interest.

 

This is a sequence of four shots taken at exactly the same period into the ignition process using a dummy barrel extending 18,0mm from the end of the cartridge. Chamber was .308 Win, Brass was Federal and the top two primers are a different make to the bottom two. Neither are magnum so it is interesting to see how much brighter the perceived flame is in the lower two images.

 

These were taken at the equivalent of 2800fps with no filtering or post image manipulation. The actual video of each test shows the ignition process slowed down to approximately 7 seconds in time

 

 

Today was not meant to be a scientific test, instead more a reference for the shift from coil spring to Belleville stack ignition however it has raised so many questions that we will go back and film again from two angles in mono and colour and with an extended range of primers and compare the Palma brass at the same time. I must point out this is not going to be a primer bashing test as I use both of these primers myself and have no plans to change them.

 

I have posted the videos of these tests on my Journal if anyone is interested.

 

What is good is that there is some data-photos and video-but what does it tells us? Generally,the primers job is done before the end of the cartridge and 18mm beyond-the thermo-dynamics within the case and it's powder being ignited make it all more complex!It's possible too that temperature and rate of pressure changes (etc) is involved, not just flash size etc-though of course,Davy,I realise that wasn't measureable here.The photos,as you say, are 'interest only' with no claims made-you were really working on that other 'thread' of lock time,which preceedes striker ignition . Of course,any movement or forces within the rifle before the bullet leaves the muzzle can affect that time,and bullet flight direction and speed.Quite likely,there is an optimum envelope for flash factors,and very likely that will vary with case design,and external temperature etc,let alone metalurgical factors relevant to actual ignition/not.Dcent pics,though,strongly suggesting some differences.

george

[baldie]

Very interesting pics Davy.

 

Personally i would be very surprised indeed if those differences didn,t equate to a velocity difference on a chronograph. The bigger , longer flames quite obviously from a larger priming compound.

 

Which is why its generally accepted that you should always work a load back up when switching primers....especially if going to a magnum version.

[brown dog]

The bigger , longer flames quite obviously from a larger priming compound.

 

Don't agree with that deduction at all; there's no measurement of intensity, or energy, temp and velocity just visible flash.

 

If you just base deductions on 'visible flash' you'd deduce that a large candle flame was more powerful than a blue bunsen/blowtorch flame.

[gbal]

Don't agree with that deduction at all; there's no measurement of intensity, or energy, temp and velocity just visible flash.

 

If you just base deductions on 'visible flash' you'd deduce that a large candle flame was more powerful than a blue bunsen/blowtorch flame.

Moths /horses / zebras....... but essentially both (Dave and BD) are correct-you would not be well advised to decide on a primer's essential properties just from its visible flash,and you would be well advised to work up (re)loads if you did change clearly specified different primer properties,as in a move to magnum primers.

george

[foxing2night]

Very interesting pics Davy.

 

Personally i would be very surprised indeed if those differences didn,t equate to a velocity difference on a chronograph. The bigger , longer flames quite obviously from a larger priming compound.

 

Which is why its generally accepted that you should always work a load back up when switching primers....especially if going to a magnum version.

I have done a lot of testing over the years and i have found that i can and do tune my load in with a primer change,,

 

not to sure that there is a difference in the velocity???

 

all testing was done for accuracy as that was my main goal,,,

 

i concluded that the difference came down to primer strength and powder column,,,,

 

all of this is no bloody good unless you have a very fast lock time and consistent firing pin strike,,,,

 

so BD i would have to disagree with your comments about the primers, there has to be a difference even if only from

manufacture to manufacture, i hear to many people say that a primer is just a primer??, it not as there are big differences,,,

 

Going a step further, earlier the other year i was having group problems with a rifle,but after a phone conversation with Mike Norris were i described the group size and shape, it was deduced that it was a primer issue,,,

 

Change of primer and low and behold i had a rifle that was shooting silly little groups,,,,,

 

all boiled down to primer verses powder column,,,,

 

Just my 2cents worth,,,,

[gbal]

I have done a lot of testing over the years and i have found that i can and do tune my load in with a primer change,,

 

not to sure that there is a difference in the velocity???

 

all testing was done for accuracy as that was my main goal,,,

 

i concluded that the difference came down to primer strength and powder column,,,,

 

all of this is no bloody good unless you have a very fast lock time and consistent firing pin strike,,,,

 

so BD i would have to disagree with your comments about the primers, there has to be a difference even if only from

manufacture to manufacture, i hear to many people say that a primer is just a primer??, it not as there are big differences,,,

 

Going a step further, earlier the other year i was having group problems with a rifle,but after a phone conversation with Mike Norris were i described the group size and shape, it was deduced that it was a primer issue,,,

 

Change of primer and low and behold i had a rifle that was shooting silly little groups,,,,,

 

all boiled down to primer verses powder column,,,,

 

Just my 2cents worth,,,,

 

I would not doubt that it can happen,but it isn't typical-changing one brand of primer for another in the same performance category won't often have much effect eg Fed 210 to 210M,or to CCI large rifle.

Maybe going from standard to mag will have a bit more effect,and there is a 'match to powder column'

effect,and pressure consequences,sometimes.So,in these senses,saying 'a primer is just a primer' is not strictly accurate,but don't expect huge transformations-you won't even get them with a change in brass case,though the good stuff's primer pockets will last longer while you try.Just occasionally,one brand of primer may fit easier too,and of course the metallurgy can vary on being struck by the firing pin.(soft etc).

My one cent,not risking two,in case they differ!!

george

[brown dog]

 

so BD i would have to disagree with your comments about the primers, there has to be a difference even if only from

manufacture to manufacture, i hear to many people say that a primer is just a primer??, it not as there are big differences,,,

 

 

You're not disagreeing, you're missing my point: There's no doubt at all that primers vary in 'power'; I'm just saying that thinking you can compare the power and rate of energy delivery of different brands by looking at the size of their visible flash is a nonsense - hence the big candle flame vs bunsen analogy.

 

eg Just looking at bunsens; the one on the left is the biggest visible flame, yet its energy delivery is so slow I'd happily wave my hand through it.

The weedy little blue flame on the right? I wouldn't put my hand near it.

[baldie]

Apples and oranges Matt. The air has been shut off to the two on the left.

[brown dog]

Apples and oranges Matt. The air has been shut off to the two on the left.

 

Is that a 'waaaa'?

 

It's to illustrate that the 'big visible flash means more energy' school of thought would deduce that the bigger brighter flame on the left has more energy than the stunted dull flame on the right.

 

But life's more complex than that and they'd be wrong.

[brown dog]

It's to illustrate that the 'big visible flash means more energy' school of thought would deduce that the bigger brighter flame on the left has more energy than the stunted dull flame on the right.

 

But life's more complex than that and they'd be wrong.

 

Just to clarify that, let's tip the pic on its side and pretend they're primer burn pics.

Amazing how the pic shows how much more energy is coming out of those top two primers isn't it?

 

 

(But because in real life we know more about them than just how long and bright the flames are, we know the bottom flame actually has about twice as much energy as the top flame - you could say 'flash dazzles us' ho ho )