Barely visible primer strikes

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huntingfish

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Hi! Wanted to shoot a few rounds this weekend to ensure everything is ok with my Zastava M70 bolt rifle in 300 winmag. Rifle went "click", but the shot didn't go off. Waited a minute or so, then tried again with a different bullet, same thing happened.

I usually pay attention to store my rifle in the uncocked position so the firing pin spring doesn't lose its strength.

I did remove and re-install my trigger on this rifle (changed my mind on installing an aftermarket trigger)...but I don't think that would cause light primer strikes, would it?

I do recall having to look online on how to unlock a the bolt (by pushing it against a flat surface to allow to rotate the back of the bolt in the correct position). Not sure if this could cause problems....doubt it.

Not exactly sure how to troubleshoot. Any help would be greatly appreciated.

I found this video...I was doing to dissassemble the bolt and clean it up. https://www.youtube.com/watch?v=1seGCL9rBNE

Cheers,
David
 
It could be the sear engagement out of adjustment (when the trigger was removed and reinstalled), it could be the trigger installation itself, it could be a headspace issue with your ammo, it could be your firing pin protrusion, it could be waxy old grease on the firing pin spring, etc etc … luckily those actions are really simple to work on.

I’d start with a cleaning and then look at sear drag, since the trigger was out it’s most likely something caused by reinstallation.
 
You mentioned having removed the bolt shroud - "unlock a bolt" - I had one brought to me that would not fire - the guy stopped one turn short when he re-installed it. The shroud needs to turn all the way until tight against the bolt, then needs to back up slight amount for cocking piece to drop into place.
 
My son and I had random periodic light strikes with our 7x57's. Not suggesting that is the problem in OP's case. Son's rifle is a model 70 and mine a Steyr-Daimler-Puchs MS. First day with his rifle my son went click on a doe. He pocketed the cartridge and an hour later shot a buck. It turned out the primers on the 4 boxes of winchester cartridges we bought had some really deep-seated primers. No problem with any other handloads or factory ammunition. The distributor claimed there were no reported problems with that lot number. Store gave me an in-store credit for the rounds we didn't fire trying to troubleshoot the issue. I haven't done any business there after spending the credit.
 
Firing pin protrusion should be a minimum of about .045"... out to a maximum of about .065"... deep seated primers shouldn't be a problem in itself... not seated deep enough can misfire due to the primer anvil not into the priming compound enough to make the primer sensitive.

I think this is most likely a rifle problem... hopefully cleaning solves it...
 
guntech said:
Firing pin protrusion should be a minimum of about .045"... out to a maximum of about .065"... deep seated primers shouldn't be a problem in itself... not seated deep enough can misfire due to the primer anvil not into the priming compound enough to make the primer sensitive.

I think this is most likely a rifle problem... hopefully cleaning solves it...
Click to expand...

It just seemed suspect that primer depth on all those cartridges was all over the map and we got light stikes occassionally with two different rifles. I have since stripped and cleaned both bolts but had no issues once other factory ammunition became available. Likewise with my 7mm reloads. Possibly a combination of needing a deep clean and closing the bolt without the necessary authority or firmness. I don't think the ammo helped as the flush primers always fired.
 
OP, you will find your answer in one of three of these posts and it could be either or a couple of them.

Primers and primer pockets are not all created equal. If your ammo is factory, it should be fine. If it's a handload, there is a chance that the primer wasn't seated all the way to the bottom of the primer pocket and when the firing pin strikes it, all it does is push the primer to the bottom of the pocket without enough force left to impact the primer hard enough to create ignition of the priming compound.

As for the bolt not being turned in far enough, this can happen but usually one turn of those threads is more than the firing pin will protrude and there won't be any mark at all on the primer. Not sure about the Zastava but it should be pretty close to that of any 98 type Mauser bolt.
 
This reminds me of one of my "scary stories from the range".... So I'm minding my own business putting some down range with my .308. An older Gent a few benches down is trying to get some down range but having problems. He comes over and says "you are shooing .308 right? Me too- can you come look?" He has a Ruger bolt action- not sure the model but nice and pretty new looking. He shows me a cartridge (factory Hornady load) and it has just a very light strike but nearer the edge of the primer. I'm thinking the firing pin is broken- single load and click, no bang. so pull the bolt and pin seems good- pretty good extension and tip looks perfect. Hmmm... Take a look at the rifle chambering and it is a .300 win mag.... Sir- I think I have found your problem...

As for the OP issue- report back if a cleaning fixes this. If the firing pin is intact then a good cleaning hopefully brings it back...
 
Just want to add some clarifications about the ammo. I "trust" that these rounds weren't the problem. This was an opened box that was left over from last year. I had shot several rounds from that box and they all performed well. They have been carried in the field, but there was no noteworthy downpour or anything like that that might of dampened the gunpowder or anything like that. The primers all look like the ones that have been fired (no noteworthy difference between the seating of those fired and those that weren't).

They are nosler trophy grade accubond 180gr (300 win mag).

Also, visual inspection of the rounds shows a very light mark where the firing pins struck the primer.

David
 
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Well - If the rifle shot that ammo well before you removed the trigger and played with the bolt shroud, you can assume the problem is mechanical and self-induced. Answers were given in previous posts.
 
Thanks Cosmic! That's the same conclusion I came to as well.

I've dissassembled the bolt (this was my first time doing so). Man, those springs are pretty strong!

The dirt wasn't that bad, but everything was very shiny. As though it was soaked in oil or something similar. Although I don't recall doing so, it would be the kind of thing I'd do, to spray a tiny bit of firearm oil in the gas ports "just to make sure everything is oiled up just right so nothing rusts up". I think I may have done the exact opposite though...I seem to see a tiny bit of a red coloration from inside the bolt.

I've put the pictures in a google album:
https://photos.app.goo.gl/9fPHSfKAVB8ZR7EB8

When reassembling...where should I put gun grease and or oil?

Also, once everything is reassembled, I was thinking of test it on spent cases. I'd mark the previous primer strikes with a permanent marker and watch for a new strike. That's the only way I can think of to actually test this while at home. Of course, the real test will be at the range.

David
 
Potashminer said:
You mentioned having removed the bolt shroud - "unlock a bolt" - I had one brought to me that would not fire - the guy stopped one turn short when he re-installed it. The shroud needs to turn all the way until tight against the bolt, then needs to back up slight amount for cocking piece to drop into place.
Click to expand...
I would put my money on this being the cause. If the owner says it couldn't be, I would double my bet.
 
Leeper said:
I would put my money on this being the cause. If the owner says it couldn't be, I would double my bet.
Click to expand...

Usually the firing pin tip won't protrude far enough to leave a mark under such conditions with a 98 type action.

Because of your post, I went out this morning an tried to duplicate the OPs issue, including on a Zastava M70 chambered for the 270Win that's in for a bedding job.

Both of the milsurp actions would not allow the firing pin to protrude far enough out of the bolt face to touch the primers.

However, the Zastava action did allow about .010 protusion beyond the bolt face.
 
bearhunter said:
Usually the firing pin tip won't protrude far enough to leave a mark under such conditions with a 98 type action.

Because of your post, I went out this morning an tried to duplicate the OPs issue, including on a Zastava M70 chambered for the 270Win that's in for a bedding job.

Both of the milsurp actions would not allow the firing pin to protrude far enough out of the bolt face to touch the primers.

However, the Zastava action did allow about .010 protusion beyond the bolt face.
Click to expand...

Appreciate the mesurements!

I've cleaned and put everything back together. I will most probably give that a try this week-end.

Cheers,
David
 
huntingfish said:
Appreciate the mesurements!

I've cleaned and put everything back together. I will most probably give that a try this week-end.

Cheers,
David
Click to expand...

I didn't go back and read the posts but are you sure the tip of the firing pin isn't broken off??? If it's no longer rounded but has a sharp point or flat, it has been damaged.

I saw one a while back that came in and it looked like one side of the pin had sheared away and it wouldn't ignite a primer. I will admit that was definitely a one off and may have been caused by exessive pressures.

It wasn't an uncommon thing to see rifles with burned off, irregular firing pin tips because they got burned away after piercing primers. Not so much today though, especially with factory ammo. Most of this condition happened with surplus ammo or handloads
 
Sorry, I looked and agree that firing pin tip looks good to me as well.

If your firing pin doesn't strike dead center, you can use one of the fired cases to test your strike point without fear of harming the firing pin tip.

It should show two distinct strike marks, one from the original firing strike and another from your test.
 
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