Misfires

[Trevor Rhodes]

What brand and number primers. Federal goldmatch work well in all actions.

[Willy]

I copied this from a previous post I made
KHGS is on the money.


Well, so I thought and proceeded to blame the gunsmith for not getting the headspace correct. After driving about 280 km and having
many misfirings I was looking to blame someone, it must be a personality defect. So what was wrong. On measuring my firing pin extrusion on my Panda action it was measuring .045 or about 10tho under recommended, the cases I was were using were fired just once but on full-length sizing were about 8 tho under a fired round from shoulder to bottom of the case and the fact that I was using CCI small magnum primers a primer that has a reputation for tough skin. All this together made for the rifle not to fire.
I have since on taking my gunsmiths advice and jammed the projectiles with a decent amount of neck tension and used new brass wala they now go bang. Apology in-coming.


The link below is probably one of the best youtube clips on explaining headspace with the view of a cutaway chamber.

https://www.youtube.com/watch?v=vAgjvBxzng4

Thanks, that is a good video. My brass is fire formed and neck sized only, so I don't think there is a headspace issue. I measured the firing pin protrusion and it came in at 47thou. I'm not sure what it is supposed to be though.

[Willy]

What brand and number primers. Federal goldmatch work well in all actions.

They are Magtech No. 9 1/2. First ones I ever bought. I just bought CCI No. 200 to give them a try.

[Willy]

Do you mean the C shape? That's just the branding. I will try that with the bolt, it has sat clocked in the safe for a long time.

Therein lies your problem!! New spring will fix it.
Keith H.[/quote]
I just spent my evening messing around with the bolt. The spring seems quite firm, I am unable to cock it with my bare hands. I pulled it apart and cleaned it thoroughly. I found that it has the small bolt head retainer so I will look at getting that changed. The firing pin protrusion is 47thou, I'm not sure what it should be exactly. I will order a new spring anyway, along with the beefier bolt head retainer and drop it in to the gunsmith. I'm curious to see how it goes this weekend with new primers.

[lonerider43]

Tim L,GSells ive seen this happen out here a few times
not by me happily.
old omarks seem to be notorious for week springs.

[Rich4]

Do you mean the C shape? That's just the branding. I will try that with the bolt, it has sat clocked in the safe for a long time.

Therein lies your problem!! New spring will fix it.
Keith H.

I just spent my evening messing around with the bolt. The spring seems quite firm, I am unable to cock it with my bare hands. I pulled it apart and cleaned it thoroughly. I found that it has the small bolt head retainer so I will look at getting that changed. The firing pin protrusion is 47thou, I'm not sure what it should be exactly. I will order a new spring anyway, along with the beefier bolt head retainer and drop it in to the gunsmith. I'm curious to see how it goes this weekend with new primers.[/quote]


Not sure what diameter the firing pin is? But 0.047” shouldn’t be too far of, it’ll definitely go bang at that, your looking for a true hemisphere ie .080 pin equals.040 protrusion, in my own research anywhere between.030 and .060 I’ve read as a recommendation for varied actions

[AlanF]

No-one's mentioned the possibility of headspace issues. If you aren't jamming the projectiles, it might be worth trying to see if the problem remains?

[bruce moulds]

I copied this from a previous post I made
KHGS is on the money.


Well, so I thought and proceeded to blame the gunsmith for not getting the headspace correct. After driving about 280 km and having
many misfirings I was looking to blame someone, it must be a personality defect. So what was wrong. On measuring my firing pin extrusion on my Panda action it was measuring .045 or about 10tho under recommended, the cases I was were using were fired just once but on full-length sizing were about 8 tho under a fired round from shoulder to bottom of the case and the fact that I was using CCI small magnum primers a primer that has a reputation for tough skin. All this together made for the rifle not to fire.
I have since on taking my gunsmiths advice and jammed the projectiles with a decent amount of neck tension and used new brass wala they now go bang. Apology in-coming.


The link below is probably one of the best youtube clips on explaining headspace with the view of a cutaway chamber.

https://www.youtube.com/watch?v=vAgjvBxzng4

Hey Scott , good to hear ya got it sorted !
I had the same problem with my Panda ( best action evvveeerrr loll !) on the weekend! I was in the middle of a ripper string then ...CLICK ! Then just got a bit out of sink with the wind and dropped a couple of 5’s very annoying! Same thing happened a fortnight ago , same range Dalby ! Click no bang but conditions were kinder and was able to get away with it !

But it always helps if you put primers in them to light the powder I found out !! Dohhh !

lucky you weigh your primers.
weighed primers always shoot better when you don't put them in.
bruce.

[KHGS]

Do you mean the C shape? That's just the branding. I will try that with the bolt, it has sat clocked in the safe for a long time.

Therein lies your problem!! New spring will fix it.
Keith H.

I just spent my evening messing around with the bolt. The spring seems quite firm, I am unable to cock it with my bare hands. I pulled it apart and cleaned it thoroughly. I found that it has the small bolt head retainer so I will look at getting that changed. The firing pin protrusion is 47thou, I'm not sure what it should be exactly. I will order a new spring anyway, along with the beefier bolt head retainer and drop it in to the gunsmith. I'm curious to see how it goes this weekend with new primers.

Not sure what diameter the firing pin is? But 0.047” shouldn’t be too far of, it’ll definitely go bang at that, your looking for a true hemisphere ie .080 pin equals.040 protrusion, in my own research anywhere between.030 and .060 I’ve read as a recommendation for varied actions [/quote]

Correct firing pin protrusion IMO is from .052" to .062". I adjust short protrusion of any firing pin where misfiring is an issue. With Omarks, particularly the low S/N ones the whole ignition system will need an update as I outlined in an earlier post in this thread, I have carried out these adjustments to hundreds of Omarks over the years. These issues have been exacerbated by the introduction of adaptors and aftermarket triggers. The adaptor issues are with the locking lug abutments placed too far back thus reducing firing pin fall and reducing, and in some cases removing all primary extraction, trigger issues are usually traced back to incorrect installation affecting bolt timing. What I have written here is based on many years of working on Omarks, you are welcome of course to "second guess" me if you wish, your prerogative. On another matter, it is an infringement on standard shooting rules to use an Omark fitted with the old bolthead retaining pin THIS IS A SAFETY ISSUE!!!
Keith H.

[UL1700]

No-one's mentioned the possibility of headspace issues. If you aren't jamming the projectiles, it might be worth trying to see if the problem remains?

My brass is fire formed and neck sized only, so I don't think there is a headspace issue. I measured the firing pin protrusion and it came in at 47thou.

Look like that one should be ticked off the list.

[pjifl]

In my opinion, the design of the spring compression in an Omark is just too close to the limit. Better designed ignition systems may not last a lifetime, but the Omark often needs new springs far too often.

One thing to watch. If you have a tool to facilitate compressing the new spring during assembly, be careful NOT to compress it more than you need. You can wind it through well past the point where the locking pin can be inserted which is a bad thing to do. It may help to make it last a bit longer to watch this.

I suspect that the replacement springs we get for Omarks are not as good as the originals. It would have been better if the designers had accepted a slightly longer lock time.

Peter Smith.

[Malcolm Hill]

The firing pin springs sold by SARA are a stronger heavier duty spring than the originals. I have never had a misfire in any Omark that is properly set up when using one of those. As Keith said it is not legal to use an Omark on the range if it is still fitted with the early small diameter bolt-head locking pin. Regards Malcolm.

[superx10]

Hi Graham, mate, a lot of good advice in this thread. Hope to see you at QLD queens that is watching your bullets go through the Hex targets in real-time . hahhah

[Willy]

Therein lies your problem!! New spring will fix it.
Keith H.

I just spent my evening messing around with the bolt. The spring seems quite firm, I am unable to cock it with my bare hands. I pulled it apart and cleaned it thoroughly. I found that it has the small bolt head retainer so I will look at getting that changed. The firing pin protrusion is 47thou, I'm not sure what it should be exactly. I will order a new spring anyway, along with the beefier bolt head retainer and drop it in to the gunsmith. I'm curious to see how it goes this weekend with new primers.

Not sure what diameter the firing pin is? But 0.047” shouldn’t be too far of, it’ll definitely go bang at that, your looking for a true hemisphere ie .080 pin equals.040 protrusion, in my own research anywhere between.030 and .060 I’ve read as a recommendation for varied actions

Correct firing pin protrusion IMO is from .052" to .062". I adjust short protrusion of any firing pin where misfiring is an issue. With Omarks, particularly the low S/N ones the whole ignition system will need an update as I outlined in an earlier post in this thread, I have carried out these adjustments to hundreds of Omarks over the years. These issues have been exacerbated by the introduction of adaptors and aftermarket triggers. The adaptor issues are with the locking lug abutments placed too far back thus reducing firing pin fall and reducing, and in some cases removing all primary extraction, trigger issues are usually traced back to incorrect installation affecting bolt timing. What I have written here is based on many years of working on Omarks, you are welcome of course to "second guess" me if you wish, your prerogative. On another matter, it is an infringement on standard shooting rules to use an Omark fitted with the old bolthead retaining pin THIS IS A SAFETY ISSUE!!!
Keith H.[/quote]
Thanks for the advice. Buggered if I can find my calipers tonight to measure that pin. I've ordered a new spring and bolt head retaining pin from SARA. My rifle does have an adaptor on it, not sure what trigger it is... If I continue to have issues with the new primers and new spring I'll put it into the gunsmith to have the pin protrusion and the locking lug abutments looked at. Given that I've had the rifle for a few years and it's a new problem, I think you were probably right in the first instance: a tired spring.

[GSells]

I copied this from a previous post I made
KHGS is on the money.


Well, so I thought and proceeded to blame the gunsmith for not getting the headspace correct. After driving about 280 km and having
many misfirings I was looking to blame someone, it must be a personality defect. So what was wrong. On measuring my firing pin extrusion on my Panda action it was measuring .045 or about 10tho under recommended, the cases I was were using were fired just once but on full-length sizing were about 8 tho under a fired round from shoulder to bottom of the case and the fact that I was using CCI small magnum primers a primer that has a reputation for tough skin. All this together made for the rifle not to fire.
I have since on taking my gunsmiths advice and jammed the projectiles with a decent amount of neck tension and used new brass wala they now go bang. Apology in-coming.


The link below is probably one of the best youtube clips on explaining headspace with the view of a cutaway chamber.

https://www.youtube.com/watch?v=vAgjvBxzng4

Hey Scott , good to hear ya got it sorted !
I had the same problem with my Panda ( best action evvveeerrr loll !) on the weekend! I was in the middle of a ripper string then ...CLICK ! Then just got a bit out of sink with the wind and dropped a couple of 5’s very annoying! Same thing happened a fortnight ago , same range Dalby ! Click no bang but conditions were kinder and was able to get away with it !

But it always helps if you put primers in them to light the powder I found out !! Dohhh !

lucky you weigh your primers.
weighed primers always shoot better when you don't put them in.
bruce.

Yes Bruce , that one was very light unfortunately!
The thing is I've done it twice is as many weeks lol!

As a young Lady from Gundy would say " That's a ROOKY MISTAKE ! " .