question about light primer strikes

[taliv]

this is an odd bit of data i can't seem to make sense of. brief facts:

I have a new pistol that takes glock 17 pattern mags. it shipped with a magpul glock mag.
with that mag, it is having a fairly large frequency of fail to fire. perhaps, 10%.
I am shooting reloads (147g). After the first two trips to the range, I have loaded new ammo and took every effort to ensure primers are seated firmly and inspected all rounds to make sure they were slightly below flush, but on the 3rd trip today, it is still occurring. visible inspection after attempting to fire, is mixed. some appear very light and some appear very deep.

now, here's where things get weird. I bought a 33 round glock factory mag. I have yet to experience a failure with the factory glock mag. perhaps 60 rounds through it.

I also shoot the same load in my cz scorpion micro, and have no issues.

so.... the question is, is it possible for a magazine to affect whatever is going on between the primer and firing pin? or is that just a statistical anomaly after relatively low round count and red herring

 

[Ironicaintit]

Is there a magazine safety (disconnect) involved?

 

[Bacon buster]

Some pistols will not fire without the magazine some will. If it won’t fire without the mag then I would suspect the mag your having issues with is the issue.

 

[taliv]

good idea! i didn't know and had to check. it will fire without a magazine inserted, so i assume no magazine disconnect is involved

 

[Bacon buster]

What pistol is it exactly? I know you said it uses Glock mags but I assume it is not Glock brand?

 

[taliv]

it's not a glock.

 

[Walkalong]

Some striker fired pistols struggle to set primers off if there is too much oil in the striker channel.

Primer seating, an old post:

Primers need to be seated until the anvil legs touch the bottom of the primer pocket (Minimum), and then a little more so the cup pushes down around the legs, up until it hits the bottom of the primer pocket (Maximum).

If seated to little (Anvil legs not touching the bottom of the primer pocket), the firing pin has to seat it fully and then have enough energy left over to crush the priming compound between the cup and the anvil. Sometimes it does not, these are the ones that so often fire on the second try. The first try seats them fully, the second try fires them.

bds has some great primer pics here somewhere that shows the cup and anvil and how they are positioned with each other prior to seating. The anvil legs are sticking out of the cup just a little bit.

After fully seating the anvil's legs and the primer cup is hard against the bottom of the pocket, it takes a great deal of pressure at this point to damage the primer so much it fails.

It is fairly easy to seat a primer too soft, not fully seating it, so that it misfires, but difficult to seat them so hard it damages them to the point of not firing. This statement is based on my decades of seating primers with various tools. I have never had one fail from being seated to hard/deep. Not saying that with some primer tools and some gorilla grips it can't be done, but it is 100/1000 times less likely to happen than seating one too shallow/soft.

We have threads here all the time when failures to fire end up being primers seated too softly/shallow. I can't remember one where it turned out someone managed to crush a primer into submission. I would suggest to all to try it. Some priming systems simply cannot do it for mechanical reasons. Some might have enough travel to do it if you have the strength, That cup surrounded by the brass primer pocket is tough to crush. Very tough.

 

[taliv]

right, walkalong. that's why i went to considerable effort to eliminate the obvious suspect

 

[Obturation]

Possibly (but not probably) at times the bolt/slide (whichever applies) is being held slightly out of battery? Maybe give the reciprocating part a firm tap with your palm before each shot to see if it alleviates the issue with the magazine in question.
Just brainstorming and may be completely off.

Good luck!

 

[Walkalong]

now, here's where things get weird. I bought a 33 round glock factory mag. I have yet to experience a failure with the factory glock mag. perhaps 60 rounds through it.

That is weird, and makes no sense. But if it repeats its self, the question is how does the one mag interfere with the firing mechanism.

 

[Bacon buster]

Are you using any modified springs, lightened striker or such?

 

[243winxb]

A weak mag spring doesnt move the round up fast enough. The round enters the chamber on a different angle. The round is not fully chambered at the time of the pin strike.

But some times applying just a hair more taper crimp, allows the rounds to chamber better.

Not all disconnectors are the same.

 

[herrwalther]

Does this firearm have failure to fire issues with factory ammo? Even if you exclusively reload your rounds, factory ammo can be quite diagnosing. What kind of primers do you use for the handloads? I have noticed CCI primers tend to be the softest for all firearms compared to other brands.

 

[tarosean]

Factory Glock mags are their best strong point IMO.

If the gun in question works with factory mags. Feed it what it likes and ditch the subpar BS.

 

[taliv]

Are you using any modified springs, lightened striker or such?

Bought some but haven’t installed it yet

 

[taliv]

Does this firearm have failure to fire issues with factory ammo? Even if you exclusively reload your rounds, factory ammo can be quite diagnosing. What kind of primers do you use for the handloads? I have noticed CCI primers tend to be the softest for all firearms compared to other brands.

Dunno yet. Only a couple range trips and I was hoping not to have to use up any of my factory ammo yet.

I am using cci small pistol

 

[taliv]

Factory Glock mags are their best strong point IMO.

If the gun in question works with factory mags. Feed it what it likes and ditch the subpar BS.

That’s what I’m thinking too but I just don’t know how the mag could cause it. 243win has a plausible theory though

 

[Bacon buster]

I would check crimp just to make sure you’re not over crimping. If it was under crimped I think you would have failure to go into battery.
Check the striker channel. It may have a burr and need a light buff. Look for scaring on the striker for improper engagement or disengagement of the plunger check for a cracked striker spacer sleeve as well. I still think that if it works good with the other mag then the mag you are having issues with is the issue. But on a new gun it’s still a great idea to inspect the above after some use

 

[tarosean]

That’s what I’m thinking too but I just don’t know how the mag could cause it. 243win has a plausible theory though

Did you round up your failed rounds and inspect the primers?

 

[Pat Riot]

Possibly (but not probably) at times the bolt/slide (whichever applies) is being held slightly out of battery?

With all you’ve stated this ^^^^^ was what I was thinking as well. Perhaps the magazine is a little oversized to the rear or there is a mold line our something not allowing the slide to fully engage?

 

[FFGColorado]

it's not a glock.

Why the reluctance to say what brand the gun is? Might help in your research..

 

[Bacon buster]

I can understand the reservation of saying what it is I didn’t ask anymore questions in that direction about the specifics out of respect for the op. At this point doesn’t really matter.

 

[Bacon buster]

Gun won’t fire if it’s not in battery if all the safeties are in place and functioning.

 

[taliv]

Nothing conclusive yet but my order of 10 more magpul mags showed up a couple days ago and I took some out today. all the failures are apparently occurring with just a single mag. So I have separated that mag and will dispose of it if this trend continues.

 

[Zendude]

If there is evidence of a light strike on the primer, then it should only be 4 things at play: inconsistent primer cup hardness, firing pin dirty/defective, firing pin spring dirty/defective, or a headspace issue with the round not being positioned firmly against the receiver.