Primer choices

[Nevada Mike]

Had a weird experience today. I was shooting the .404J and had a round misfire - first time ever with this rifle. I had another load that leaked carbon and completely covered the head of the cartridge, but no blowback or other obvious issues upon firing. The fired primer was slightly proud of the case head. Both primers were Winchester Large Rifle Magnum primers.

These were my practice loads - 36 grains of 5744 under 400 grain cast, powder coated bullets, with gas checks. The misfire was Hornady brass, primer deeply indented and should have ignited but didn't. The one that apparently leaked was Hornady brass - unknown number of firings, but is one of a lot that has been very reliable.

So I am wondering if this is a brass problem, a primer problem, or a primer SEATING problem? I have other primers I could use - CCI 250 and Remington 9-1/2M. Any advice?

Thanks,

Mike

 

[fourfive8]

My guess- too much headspace or minimal headspace control. Usually shows up with reduced loads as the primer unseats inteslf upon firing but the lower pressure of the load does not fully re-seat the primer as the case head is not forced back against the bolt face as would be the case with a full pressure load.

To test... don't change a thing except load up a full pressure load with powder of choice. Compare results. The FTF primer is likely a result of excessive headspace where the force of the firing pin strike was absorbed by the cartrdige moving forward. The 404J does not have a large, sharp shoulder nor belt to assure positive headspace control. Full pressure loads will many times mask symptoms of excess headspace. The reduced case life will show the road as case stretching is taking place with each firing and sizing. Remedy? try adjusting the sizing die for minimal necessary sizing.

 

[Nevada Mike]

My guess- too much headspace or minimal headspace control. Usually shows up with reduced loads as the primer unseats inteslf upon firing but the lower pressure of the load does not fully re-seat the primer as the case head is not forced back against the bolt face as would be the case with a full pressure load.

To test... don't change a thing except load up a full pressure load with powder of choice. Compare results. The FTF primer is likely a result of excessive headspace where the force of the firing pin strike was absorbed by the cartrdige moving forward. The 404J does not have a large, sharp shoulder nor belt to assure positive headspace control. Full pressure loads will many times mask symptoms of excess headspace. The reduced case life will show the road as case stretching is taking place with each firing and sizing. Remedy? try adjusting the sizing die for minimal necessary sizing.

Thanks for your response. I considered this as a possible cause, but have fired about 100 rounds through this rifle so far - about half of them were this same reduced load - the others were load development rounds up to max pressure for the 404 CIP specification - and no problems. So this was a 'one-off' event. I did discuss headspace with Reto (the maker) and he assured me that he always cuts the headspace "tight", especially on cases like the 404J.

I thought it could be the Hornady brass. Haven't had this problem with the Norma brass. Could the primer pockets be stretched from previous firings? If so, I'll just toss all the Hornady stuff and proceed with the Norma and RWS brass. I think that a DG rifle should be utterly reliable with no exceptions.

 

[Wyatt Smith]

Did the primers seat really easily? How many times was this brass fired? The tightness of the primer pockets is how I tell when to discard brass.

 

[Mike Van Horn]

Sounds like two different problems.
1. bad primer with the misfire
2. loose primer pocket the other. Could be the brass or. You may try different brand of primer. Not all primers are the same size, federal seems to be a little large, in fact some people have reported them hard to seat. In my experience Winchester has been on the small side

 

[Nevada Mike]

Did the primers seat really easily? How many times was this brass fired? The tightness of the primer pockets is how I tell when to discard brass.

I used normal seating pressure, IIRC. I got the Hornady brass second hand, so unsure how many times it has been fired. Once or twice by me. I think I'll 'retire' the Hornady brass, as I was suing it for practice loads to save my new Norma and RWS brass. 404 brass is difficult to source right now.

Sounds like two different problems.
1. bad primer with the misfire
2. loose primer pocket the other. Could be the brass or. You may try different brand of primer. Not all primers are the same size, federal seems to be a little large, in fact some people have reported them hard to seat. In my experience Winchester has been on the small side

I think you are right - the misfire was a bad primer. Makes me question the whole lot of primers. I will go to a different lot. This is the first time I have had a misfire with Winchester primers... the firing pin made to normal, deep indent and... nothing. It was really weird that I had the blow back AND the misfire in the same short bench session.

Going down to my range again this AM and work on refing a couple loads.

I am really liking this 404J rifle/cartridge combination.

 

[Ray B]

I've read that some of the new production primers are being made with a different compound- not lead, As with any new compound there is possibility of unreliability. Not sure if Winchester has changed compounds or not.

 

[fourfive8]

Had a weird experience today. I was shooting the .404J and had a round misfire - first time ever with this rifle. I had another load that leaked carbon and completely covered the head of the cartridge, but no blowback or other obvious issues upon firing. The fired primer was slightly proud of the case head. Both primers were Winchester Large Rifle Magnum…..

Leaked gas around primer without damaging gun or obvious blowback through action indicates low pressure. Primers seal against the primer pocket wall as pressure reaches a level to expand the primer cup walls. Low pressure load not adequate to seal gas as primer unseats itself after firing. Force of firing pin strike does not force cartridge forward nearly to the degree that the primer detonation does. Primer detonates. Cartridge forced forward as primer forced rearward. There is a sequence of events involved when a cartridge fires- it’s not a single event.

Primer “proud” of case head after firing. The ONLY way this happens is when excess headspace is combined with low
pressure. As a certain minimum chamber pressure is reached, usually in the 30k psi + range.,. the case neck and upper body wall will temporarily “stick” to the chamber wall while the case head just forward of the web stretches rearward as the head slams against the bolt face. If the primer has unseated itself some because of extra headspace, it will be reseated. This will sometimes show a flattened primer even though the pressure is in normal range and will mask the condition of extra or excess headspace.

I know the common blame goes to bad brass, bad primer, weak firing pin
spring, etc. But excess headspace and/or incorrect, excessive sizing can cause the symptoms described.

Should not be discounted.

 

[Nevada Mike]

Leaked gas around primer without damaging gun or obvious blowback through action indicates low pressure. Primers seal against the primer pocket wall as pressure reaches a level to expand the primer cup walls. Low pressure load not adequate to seal gas as primer unseats itself after firing. Force of firing pin strike does not force cartridge forward nearly to the degree that the primer detonation does. Primer detonates. Cartridge forced forward as primer forced rearward. There is a sequence of events involved when a cartridge fires- it’s not a single event.

Primer “proud” of case head after firing. The ONLY way this happens is when excess headspace is combined with low
pressure. As a certain minimum chamber pressure is reached, usually in the 30k psi + range.,. the case neck and upper body wall will temporarily “stick” to the chamber wall while the case head just forward of the web stretches rearward as the head slams against the bolt face. If the primer has unseated itself some because of extra headspace, it will be reseated. This will sometimes show a flattened primer even though the pressure is in normal range and will mask the condition of extra or excess headspace.

I know the common blame goes to bad brass, bad primer, weak firing pin
spring, etc. But excess headspace and/or incorrect, excessive sizing can cause the symptoms described.

Should not be discounted.

I thought of this and measured the resized brass. And the fired brass. Very little difference that I could detect, but I deciided (for practice loads only) to simply neck size the brass by re-adjusting the die to size the neck to just slightly above the shoulder. No far problems observed with the practice rounds at the range this AM.

 

[RockSlinger404]

There was an issue with Winchester primers a few years ago, however if I recall recorrect it was with the Large Rifle and not the Magnum primers. Regardless, some of these primers leaked a caused damage to your bolt face. Since then I switched to CCI and have not had one misfire in different calibers with different makes of brass, all seated with a RCBS hand primer. If it were me, I would just make the switch now, while you are still doing load development.