Blown primers factory ammo

[Moose83]

Has anyone else had this happen to them before? The ammo was the Norma Whitetail line , 100gr sp in .243 Win. I actually don't shoot much factory ammo, but they had this stuff relatively cheap locally and I figured I could have some nice brass to reload when I got through it all. I've already put 5 boxes of it thru my tikka with good results out to 600 yards and haven't had any issues. I was doing some positional practice tonight and blew the first one at the end of a 9 shot string. I was shooting fairly fast and the gun was hot, but I wouldn't say any hotter than I've had it before. I wasn't sure if it was a one off thing so I tried a 10th round which also blew out the primer. I then figured it was a chamber heat issue so I put the gun aside and let it cool completely. After it had cooled I tried another 3 round mag and the 3rd cartridge blew its primer as well and almost locked up my bolt. Upon further inspection when I got home, 7 of the other fired cases showed ejector swipes. I sent an email in to Norma so I'll see what they say about it. At this point I think it's an ammunition issue but I figured I'd check here and see if anyone else has ever had this, and if there are any firearm issues to watch out for that could cause this. The rifle is a tikka t3x lite compact in .243 Win with a 1:8" twist. Ambient air temperature was 21 degrees Celsius, which isn't crazy hot and I was laying in the shade as well.

 

[Wrench]

Save the box. They're gonna want to know. You are Mega over pressure.

 

[ScreamingPotato]

I had that happen on a 270 WSM, turns out the barrel and throat had some severe copper fouling. I cleaned the living **** out of it and the problem went away.

 

[ResearchinStuff]

If your chamber has case lube built up inside of it you'll get pressure signs.

 

[sidetoss20]

I’ve heard of this happening in other Norma lines, Golden Target to be specific. You may want to reach out to Norma to see if they will help you out. As other users have mentioned, you may have some buildup of carbon or similar causing a pressure increase. Do you notice pressure signs on the other primers?

 

[Bluumoon]

I pierced a bunch of primers on .223 77gr Norma stuff during the S2H class. Enough to blow the bolt cover off. They offered to pay for repair, but that was it

 

[Weldor]

Following, I have a case of 6.5 PRC. No problems so far. average temp where I shoot in the am 65-85f . Did have similar problem, 308 gas gun suppressed though. Mostly carbon build up on the one and over gassed. The Golden target I have in prc seems really mild. 2660 fps out 20" bbl.

 

[WCB]

Save the box. They're gonna want to know. You are Mega over pressure.

Not necessarily...as others have stated could be a fouling issue. I do agree save the box or at least record the lot number and contact Norma.

 

[77TMK]

Norma has awful quality control anymore. Call them with the lot ID and have all receipts and packaging ready.

 

[sidetoss20]

OP when was the lot purchased?

 

[Moose83]

OP when was the lot purchased?

This lot was purchased a box at a time over the last 6 months from my local Canadian Tire box store.

 

[sidetoss20]

This lot was purchased a box at a time over the last 6 months from my local Canadian Tire box store.

All the same lot numbers?

As previously stated Norma QC has really suffered over the past few years, 2021 and on. The reports I have seen of similar issues date to ammo purchased in 2022 ish.

 

[Moose83]

To those who have mentioned fouling issues.. would said issues be visible to the naked eye? I maybe have 300ish rounds down the tube at this point. I dragged a bore snake through it last night to take out most of the carbon fouling and the bore and chamber look pretty shiny and clean to me in bright light. I've been following @Formidilosus train of thought on not cleaning rifles up to this point and I'm wondering if I now have one of the anomalies

 

[Moose83]

All the same lot numbers?

As previously stated Norma QC has really suffered over the past few years, 2021 and on. The reports I have seen of similar issues date to ammo purchased in 2022 ish.

Yes it's all the same lot number... obviously not a lot of factory ammo shooters in my town..lol

 

[Formidilosus]

To those who have mentioned fouling issues.. would said issues be visible to the naked eye? I maybe have 300ish rounds down the tube at this point. I dragged a bore snake through it last night to take out most of the carbon fouling and the bore and chamber look pretty shiny and clean to me in bright light. I've been following @Formidilosus train of thought on not cleaning rifles up to this point and I'm wondering if I now have one of the anomalies

No. There is no amount of powder or carbon “fouling” that is doing that.

That is a Norma ammo issue and it is not unheard of with their ammo.

 

[wind gypsy]

I bought a handful of boxes of 6 creed norma golden target and the loaded ammo necks measure 0.2750-0.2755. SAAMI chamber neck dimension is 0.277. So the ammo has less than a 0.001" clearance around the necks in a SAAMI min chamber. Throw some carbon build up in there and it's worse. The ammo is within SAAMI spec (max 0.2660 neck dia) but I wouldn't consider ammo necks 0.0015 below chamber diameter to be acceptable.

I'd be interested in how thick the necks are on the 243 loaded ammo?

 

[Moose83]

No. There is no amount of powder or carbon “fouling” that is doing that.

That is a Norma ammo issue and it is not unheard of with their ammo.

I kind of figured that, but it seemed odd to me that the first 5 boxes were perfect then this one from the same lot was like this. I did buy this ammo so I could get some decent brass for reloading, so I guess I'll just pull down my remaining boxes and reload from here on.

 

[Moose83]

I bought a handful of boxes of 6 creed norma golden target and the loaded ammo necks measure 0.2750-0.2755. SAAMI chamber neck dimension is 0.277. So the ammo has less than a 0.001" clearance around the necks in a SAAMI min chamber. Throw some carbon build up in there and it's worse. The ammo is within SAAMI spec (max 0.2660 neck dia) but I wouldn't consider ammo necks 0.001 below chamber diameter to be acceptable.

I'd be interested in how thick the necks are on the 243 stuff?

I'll check when I get home from work.

 

[eoperator]

I had a similar problem with 6.5cm berger ammo piercing/blowing primers out in a bergara rifle. Ammo was sent back to berger and pressure tested well within sammi specs. Bergara ended up replacing the bolt because the firing pin hole was to large not giving enough support to the primer.

 

[wind gypsy]

I wouldn't be surprised if cleaning your chamber/bore made the issue go away. Edit to add: that doesn’t mean Norma might not be loading too close to the margins in some aspect.