OzFclass

I have a Barnard P Action with a couple of hundred rounds through it that gives a very delicate primer strike. I use CCI BR LR primers which are fairly hard but I would expect a deeper impact.

I have had 22 misfires where the primer is struck but has not fired, popping the primers out and clouting them with a hammer set them off so the primers were not defective in that respect. I was fire forming at the time so in theory the case could move forward slightly but I had built them with a long COAL so the bullet had a 5 thou jam which in theory should keep the case in place and it is not exactly rattling around in the chamber either. (It is a 7mm SAUM wildcat with steeper shoulders)

I always back the knurled screw off and take the tension off the firing pin spring when not in use so the spring should be fine so next move is to measure the firing pin protrusion, can anyone tell me what it should be and if it can be adjusted?

Is the primer pocket depth ok, I've seen where individuals have cleaned up the primer pockets too deep causing this same problem

Cheers

These are all on new brass and I don’t uniform the primer pocket until after the first firing so they should be fine. It is Norma Brass.

Have you tried using a softer primer when fire forming your brass? Just a thought, maybe because the wildcat chamber with the steeper shoulder allows the brass to move forward slightly, enough to prevent a good solid strike of the firing pin. Doubtful.

If the cocking piece picks up the trigger too far forward you will lose firing pin fall,Tolerances on Barnards are good but this can cause your problem.

Ovenpaa,

My first suspicion would be excess headspace, but you seem to be sure the projectiles are jammed. I would try a PM to KHGS on this forum. I reckon he would have smithed more Barnard Model Ps than anyone. He may simply advise taking it back to the supplier to look at, which is what I would do.

Alan

Not sure of the design criteria for a Barnard, but considering the spring loading and the pin fall I would consider 65 t0 70 thou dry fire protrusion of the firing pin sufficient for 100% fire of CCI primers. Unless firing pin fall is way too short, a few thou more in head space ( as with new cases ) should not cause any problems. As TOM suggests if you have fitted an after market trigger it is possible the pick up is too far forward causing a short fall pin.

Barry

I am using the standard Barnard trigger box. Firing pin protrusion measures at .050" I will PM KHGS

dissassemble the bolt clean with break clean and re assemble with light maschine oil. i had the same problem with my BAT but it just had too much lube in the spring from factory. worth a try

I have literally just done that

After thorough cleaning (It looked good anyway) I now have .0530" protrusion so I gained three thou and everything looks fine. .0530" should be far more than enough as well so I am starting to think it is a combination of hard primers and a new case that still needed forming so I will load up with normal CCI LR instead of BR.

I have a competition next weekend which is shot at 400/500/600 followed by 800/900/1000 and right now I do not have enough fired brass so I have one chance this coming Wednesday morning to try and get the last of the new brass to go bang, failing that I will be shooting one of the distances with a .308.....

Just a quick question. Did you neck down the brass from 300 Cal?

If you did, when seating the projies, how did the interferance fit feel? Was it a tight fit, or loose. This may account for not providing enough resistance, so the primer can get a good hit?

Yes they are necked down from 300. I did build them to jam by .005" and I am starting to think that was not enough and they are just moving forward very slightly. I have re loaded them with CCI LR instead of the harder BR and built them .010" longer. All I can do now is wait until Wednesday and see if they go bang.

Talk about cutting it fine!

I had this problem with my brand new Barnard P action. I was using never fired Lapua .308 cases with CCI primers. Roughly 1 in 5 shots misfired.

In desperation I reamed out the primer pockets with a gadget I got from Triple J that forms a pocket to the correct dimensions. An amazing amount of brass came out and I haven't had a misfire since.

Not very scientiific I know...

Geoff.

I've been working my way through fire forming 200 ADI 223 cases with CCI BR4 primers and got my first ever misfire last week. Put it down to one bad primer and load it up with this weeks rounds. Get out there this week and I get another misfire

Field strip the bolt and check it over, cannot find anything wrong and the next shot is fine.

So I get home and get the bump gauge onto the cases. Unfired 2.525, fired 2.536 problem case 2.513. Yep 23 thou of head clearance did it for me.

Have just checked the firing pin potrusion on my Barnard bolt: 0.065"= 0.012" more than your measurement.

Maybe you should look at using more jam (as Bat suggested) to help promote ignition?