Thread: Primer question

I've deprimed heaps of cases over the years but someone once told me, "every time you do it, expect it to go bang", and I do. Luckily haven't shat my pants yet.......but theres still time

I have had two bangs but only when priming, never with depriming livies. When it goes and you have a full tube of primers you are expecting more bang for you buck thankfully that didnt happen. But it does make me reach for the earmuffs and safety specs.
Both occassions was pistol primers so maybe something in the fact they are thinner skinned.

Originally Posted by johnd

I have had two bangs but only when priming, never with depriming livies. When it goes and you have a full tube of primers you are expecting more bang for you buck thankfully that didnt happen. But it does make me reach for the earmuffs and safety specs.
Both occassions was pistol primers so maybe something in the fact they are thinner skinned.

Yep they are 'more sensitive' by design due to the smaller area for spring power to live in, in the frame of a pistol. Priming using the hand primers is a way to prevent pops over priming in a press where you have a lot more mechanical advantage (or with some presses anyway).

Not so much more sensative but a thinner cup. Typically 17 thou versus SR primers at 20 - 25 thou.
I use SP primers in my Hornets and get better results than with SR which have a stronger spark.
There is a risk of puncturing a primer though.

Originally Posted by blip

so don't do it with a lee loader I need to deprime some 303 brass so I can anneal it.

I happened upon a struck (dud) 303 primer in a case whilst annealing over a gas flame. Impressive bang and a convincing exit of primer. Character building stuff.

Is that another way of depriming

Originally Posted by blip

Is that another way of depriming

Indeed. Also an excellent but noisy laxative.

Originally Posted by Kiwilad2021

Ive decapped and reused 2-300 primers with no worries at all. Every single one has fired. Certainly de prime with caution as mentioned above.

I've done the same thing without any hassles, wore leather gloves & a leather apron I used to use for hay making plus of course safety specs. Never had a commercial one go off on me but like @zimmer a couple of milsurp ones go pop. I use a Lee decapping die for all my decapping & this seems to contain any aggro quite happily. The die & shell holder got a good wash out with hot water & a spray with CRC afterwards when the milsurp primers went off on me, being as they were likely corrosive primers.

Originally Posted by zimmer

Not so much more sensative but a thinner cup. Typically 17 thou versus SR primers at 20 - 25 thou.
I use SP primers in my Hornets and get better results than with SR which have a stronger spark.
There is a risk of puncturing a primer though.

You are right, hence the '' around the more sensitive bit. By way of explanation for anyone not aware of how this works, the thinner cup means less force is required to get the necessary amount of crush of the priming compound between the primer's cup and anvil to successfully initiate priming compound burn when the firing pin is released. It also makes pistol primers easier to initiate during handling, or easier to ignite through improper priming techniques. When primers are shipped the anvil is not pressed home inside the primer cup, this is a way of desensitising the primers during shipping. When we prime cases, we squish the anvil back into the primer cup and against the priming compound layer inside the cup and this sensitises the primer ready for initiation by the firing pin. It's also why pistol primers are easier to ignite accidentally over other grades of primer and why pistol primers are considered easier to pierce when used in rifles but are also considered to have more reliable ignition characteristics.

Ah, almost right. CCI for example have the anvil petals sticking out. With RWS the anvil is flush with the bottom edge of the cup so you cannot preload them or push the anvil back in. With early Murom it was essential to drive the anvil in against the compound. If you didn't there was chances of erratic ignition or no bang at all. Don't know if Murom are still like that.
My practice for target ammo is to preload my BR4s by 1 1/2 thou and BR2s 2 thou preload. You cannot do that with normal priming tools. I currently use a Primal Rights tool. For sporting ammo I just seat by feel with a hand tool.

There is always the risk of overdoing it and crushing the primer material.

Before I started taking care priming I measured some of my early efforts done with an RCBS tool, carefully I thought. All primers were over seated and crushed.

One of the biggest priming issues, and I see the advise on the net, is to seat primers flush with the case base.

Originally Posted by zimmer

Before I started taking care priming I measured some of my early efforts done with an RCBS tool, carefully I thought. All primers were over seated and crushed.

One of the biggest priming issues, and I see the advise on the net, is to seat primers flush with the case base.

Curious about the last sentence here, I have a way by which I can seat flush with the case base but keen to know if that is an issue in itself or if the issue is in achieving said outcome.
For me, the jury is still out as to whether seating flush with the case base is the way to go.

Interesting thread.
I tested some primers on behalf of someone suffering misfires, who wanted to prove the primer or his gun, I didn't have the gun, or equivalent caliber so deprimed 10 cases in question and seated the primers in a cartridge I could dry fire. They all went bang at the squeeze of the trigger.
So to my experience it can be done, but as others have noted, probably best for range rounds as opposed to hunting rounds.

Originally Posted by longshot

Curious about the last sentence here, I have a way by which I can seat flush with the case base but keen to know if that is an issue in itself or if the issue is in achieving said outcome.
For me, the jury is still out as to whether seating flush with the case base is the way to go.

Primer pockets like the cases themselves (well USA ones) are governed by SAAMI specs ie a maximum and a minimum value provided for primer pocket depths for manufacturers to work to. Primers vary between brands in over all length. Maybe even between batches. You could have a primer pocket at the deepest end of the SAAMI spec (still within spec) and a primer that is shortish. Outcome if seating flush is the bottom of the primer may not be correctly in contact with the bottom of the primer pocket which can lead to erraric ignition or no ignition.

I'd have to rechech SAAMI but I think these are the specs/tolerances -
Large Rifle PP specs 125 thou to 132 thou.
Large Rifle Primer specs 123 thou to 136 thou
So a 123 thou primer seated in a 132 thou pocket, flush, will not be a good combination.

The other thing that happens is if you uniform your primer pockets with for example a Sinclair tool, which is non adjustable, you may cut your pockets too deep. I had that happen with a Sinclair tool which before I realised it was cutting my pockets to 132 thou whereas I wanted 128 thou. IIRC 132 thou is still within SAAMI spec or right on it. They refunded me for that tool.

Might be time to resurect this thread from last year

https://www.nzhuntingandshooting.co....primers-79872/

I really want to know why would you?????

if you need to re-resize the case.....if its a big long case you can left primer rod up so it doesnt touch or remove it completely.

many on here will suggest you dont need expander ball at all...

too easy to fire them off in empty case now we have suppressors..but dont try and muffle the hole in end with your new polarfleece coat it will burn wee holes like ciggy burns.