280 AI case head seperation

[Pdvdh]

I expect Hornady brass would work fine if you annealed.

Curious how annealing Hornady cases could reduce case head separations at the web just forward of the case heads? No one should be annealing at that location...

 

[vanhornsky]

Thanks for all the information gentlemen. I ordered some nosler brass so I will see how that goes.

 

[Barrelnut]

Thanks for all the information gentlemen. I ordered some nosler brass so I will see how that goes.

Vanhornsky,

You have not stated if you have a traditional Ackley 280AI chamber or the Nosler SAAMI 280AI chamber.

You CANNOT use Nosler 280AI brass in a traditional 280AI chamber!!!

Read this alert from Nosler:

https://forum.nosler.com/viewtopic.php?f=4&t=15233

 

[Pdvdh]

Re: 280 AI case head separation

Vanhornsky,
Read this alert from Nosler:

https://forum.nosler.com/viewtopic.php?f=4&t=15233

The information/alert at that link isn't written, generated, or posted by the Nosler company. It's a Thread discussion on the Nosler Reloading Forum web site, no different that this Thread is a discussion on the LongRangeHunting Forum web site.

Significance being, Nosler cannot be credited as the source for any of the information/opinions/positions expressed in that Thread on their Forum. No more than Len can be credited with any of the information being posted in this Thread on his Forum.

But I agree that use of Nosler's current 280 AI brass could be a mismatch for a 280 AI chamber cut to the original, pre-SAAMI 280 Ackley Improved headspace. There are pre-SAAMI go gauges and chamber reamers manufactured prior to SAAMI's adoption of their 280 AI in 2008, that could result in chamber headspace cut 0.014" or more deeper than the 2008 SAAMI adopted headspace specification.

But I still don't expect excessive chamber headspace of 0.014" to result in 8 out of 10 case head separations based on the single, original firing of factory ammo.

 

[vanhornsky]

Re: 280 AI case head separation

This is a brand new barrel just made by a reputable company. the barrel is a sammi spec.

 

[Barrelnut]

Van...

Phorwath is right. The link I posted is not a "Nosler Alert". It was just a poster copying a post from another forum that used that term very loosely. I would be skeptical of the content. Sorry for the added confusion.

 

[Edd]

Curious how annealing Hornady cases could reduce case head separations at the web just forward of the case heads? No one should be annealing at that location...

The pressure inside the case is pushing the shoulder forward and the base, I don't like to call it the head because I have trouble accepting the head and the neck being on opposite ends of the body, of the case rearward and stretching the case at its weak point. If the shoulder was softer there would be less tension on that weak point.

 

[vanhornsky]

Update: I have since pulled all the bullets on the super performance 280 Remington and dumped the powder out. Replacing it with h4895 42gr 139sst load as Nosler calls out in their manual. I have shot 40rounds with not one case head separation. The case measures Sammy spec exactly. So I think the original powder is too slow to fire form efficiently. Hope this helps some else.

 

[MudRunner2005]

Update: I have since pulled all the bullets on the super performance 280 Remington and dumped the powder out. Replacing it with h4895 42gr 139sst load as Nosler calls out in their manual. I have shot 40rounds with not one case head separation. The case measures Sammy spec exactly. So I think the original powder is too slow to fire form efficiently. Hope this helps some else.

The powder was not the problem... It was how much of it was in the case.

A lot of people use factory ammo to form for their AI's... I do not for this very same reason. It is too hot of a cartridge when trying to form. The brass case expands too rapidly with too much pressure and it can cause ruptures, split necks, case/head separations, etc... I use around 45 grains of RL19 with a cheap Hornady 117 Interlock for my .25-06 AI forming loads. And I use the same principal for my other Ackley Improved cartridges. I never run a full or hot load for fire-forming. But you don't want to run too light of load either. I'd use a book starter load for whatever the powder and parent case combination is.

 

[FEENIX]

Ok so I have a brand new 280AI that I am trying to fire form brand new 280 remington Hornady loaded ammo and it blows the case head off. 2 out if 10 rounds survived. Go guage closes tight. No go will not close. Measuring the fired cases it measures to sammi spec. I even took it to another smith to look at and he couldn't see a problem. Anybody else had this happen to them? I am ordering nosler loaded ammo 280 ai to see if that helps. But I have a bunch of 280 Rem. Any ideas?

Update: I have since pulled all the bullets on the super performance 280 Remington and dumped the powder out. Replacing it with h4895 42gr 139sst load as Nosler calls out in their manual. I have shot 40rounds with not one case head separation. The case measures Sammy spec exactly. So I think the original powder is too slow to fire form efficiently. Hope this helps some else.

Did you address your issue/concern with Hornady? When loaded accordingly, you should be able to fire factory .280 Rem ammo off your .280 AI in a pinch safely. Not Hornady ammo but I have done so with my improved cartridges without any issues.

 

[TOM H]

Update: I have since pulled all the bullets on the super performance 280 Remington and dumped the powder out. Replacing it with h4895 42gr 139sst load as Nosler calls out in their manual. I have shot 40rounds with not one case head separation. The case measures Sammy spec exactly. So I think the original powder is too slow to fire form efficiently. Hope this helps some else.

One question. If you followed all the instructions from Nolser on firing forming in their manual did you also seat bullet well into the lands? They mention doing that will eliminate case stretching web area with is a cause of case head separation.

I have 2-280AI. First one build before SAAMI spec 280AI and I fireform using 280 case and I'm still shooting those cases. The other one use Nosler brass.

Look at 280 case in Nosler manual. I also have 35 WhelenAI,243AI and 222AI and I can fireform any of those with factory ammo. The 222AI I fireform shooting PD.

The 280AI that Sierra/Nolser had data before SAAMI Spec 280AI, Nosler published same thing about fireforming for that case.

 

[vanhornsky]

I am not seating into the lands. Standard COAL. I am using the hornady 280 brass just with different powder. I tried many different fire forming ways. First I tried the super performance with no bullet. It did not burn very much powder in fact most of it came out the end of the barrel like a shotgun, non burnt powder flakes. Then I worked up pistol powder which worked fine. Then I decided it was the powder(super performance) that was too much pressure to fireform. I switched to the h4895 because I had it, it worked fine so I put bullets on top an went to the range. They all shot fine. Even was grouping very well. I have some Hornady Eldx loaded factory ammunition that I am going to try. We will see.

 

[TOM H]

I am not seating into the lands. Standard COAL. I am using the hornady 280 brass just with different powder. I tried many different fire forming ways. First I tried the super performance with no bullet. It did not burn very much powder in fact most of it came out the end of the barrel like a shotgun, non burnt powder flakes. Then I worked up pistol powder which worked fine. Then I decided it was the powder(super performance) that was too much pressure to fireform. I switched to the h4895 because I had it, it worked fine so I put bullets on top an went to the range. They all shot fine. Even was grouping very well. I have some Hornady Eldx loaded factory ammunition that I am going to try. We will see.

I got Hornady new manual and they formed Hornady 280 cases to test 280AI loads. They do rec using factory 280 ammo as other way to fireform.

I think someone mention calling Hornady. You should call them.

 

[bigedp51]

I bought the RCBS case mastering gauge below after I started collecting .303 British Enfield rifles. It works very well for checking case stretching and thinning in the base web area.

Below the factory loaded Winchester .303 case below stretched .009 on its first firing.

The secret to preventing case head separations is to not let the case stretch and thin on the first firing and minimum shoulder bump thereafter.


Below this Winchester .303 British case started to separate after its second firing. I have been very lucky, in over 47 years of reloading this is as close as I have ever been to a total case head separation. Meaning the RCBS case mastering gauge is far more accurate than a bent paper clip when checking for case thinning.

Bottom line, jamming the bullets into the rifling is a very simple method for fire forming cases. And this works best with faster burning powders that will blow out the shoulder but not generate enough chamber pressure to cause the case to stretch. (below 43,000 psi)

Below, it is the amount of head clearance that allows the case to stretch and thin. And as long as you can hold the case against the bolt face when fired the case will not stretch and thin. So jamming the bullet into the rifling or the false shoulder method will work the best. And on a British .303 Enfield rifle at the maximum military headspace of .074 and a rim thickness of .058 you can have .016 head clearance.