280 AI alert

[cape cove]

I wasn't aware that JE had passed. When did this take place. RIP JE Custom..

 

[carlbobh]

I wasn't aware that JE had passed. When did this take place. RIP JE Custom..

Jan 24th

Not good News, but,,,,,,,,,,,,,

I just got off the phone with JECustoms' brother. JE is not doing well. He caught the virus and is in the hospital on a ventilator. Over the years JECustom has provided LOTS of worthwhile info on this site. I hope the best for him! Just thought some of the "old timers" on this site would be...

www.longrangehunting.com

 

[MNbogboy]

This bad news just got to me, i lost the first post i started. HE always provided knowledgeable advice and I respected his opinions. rip je. I didn't hear this news I'll now as i was knocking on heaven's door myself the third week in january. I suffered a major stroke that affected my whole left side. I am slowly recovering the use of my left hand. I am also planning my annual Wyoming trip in October trying to kick that bucket like a game of kick the can. My bucket list gets a little longer each time I think of all the carp I haven't done yet but still want to.lpoking forward to being with Jesus when my day comes.

 

[CBH Australia]

A .280ai convert here.
Sorry you all lost a freind I don't think I had any posting with him.

I've read a bit on the these, more so the effectiveness of the round.

If I'm reading all this right the Original Ackley version chamber is 14thou longer than the Nosler spec production 280AI approved by SAAMI?

So, potentially using SAAMI standard spec cases in an old chamber will have excessive headspace.

I realise 14thou is a lot but i use metric for daily use being an Aussie so I don't work on imperial measurements unless discussing reloading.

I think I understand the issue and the proccess .

If done safely with appropriate loads or filler can the "Factory AI " case be fireformed to a P.O.Ackley spec .280ai chamber?

I am a novice and have no Wildcat experience but given the case is wider along the body , does it reduce the need to blow out the case body taper?

There is still the issue of the excessive headspace but can it be safely overcome with fireforming loads?

Also, the difference in the base diameter of cases. I think I read there were slight difference between the case base dia of .308 and .30-06 I'm using those as reference as I think a lot of cartridges can be derived from their cases.
The question is how critical is the variation? Let's say it's up to 5 though.

The reason I ask is I have a few Tikka rifles. Would they cut the bolt face the same for .270, .30-06 family of cases as the .308 , .243 cases?

I purchased a new .25-05 for my.280ai expecting it to have the appropriate bolt face and the correct magazine.


I hear some countries expect appropriate headstamps when entering with firearms and ammo.
It might be needed nice to have it headstamped correctly, be it for safety sake matching guns to ammo or the time comes sorting out our loading room is someone else problem.

I suspect my chamber is cut at SAAMI spec. Given the timing etc.
I have not found any issue but I will check a fired case against a new unfired Nosler .280ai for reference.
When I can contact my gunsmith I will ask him too to be sure.
I know he has .22-250ai and 7mm-08ai reamers.

I know Mr Ackley did not apply his wisdom to every cartridge or test a prototype so I wonder which ones are his. I also read that the principle or practice of the 40 ° shoulder is very effective on some cases with little improvement on others.

Is the .280ai the Only improved case that has been tampered with by the corporation's? Is it the only one with commercially available headstamped cases?

@phorwath can you chime in please.

 

[Pdvdh]

The SAAMI 280 Ackley Improved is the only SAAMI adopted cartridge I know of that has Ackley in it's name and has a different headspace than PO Ackley's version would have.

I don't know if Tikka bolt faces are cut to different diameters for the 243, 270, 280, and 30-06 cartridge chamberings. But with the Tikka style extractor, there is some latitude in cartridge case head/rim diameters that will still allow reliable extraction of fired cartridges. I don't think a case head 0.005" smaller than the machined bolt face will cause any extraction problems.

I think your primary question is, can SAAMI 280 Ackley Improved headstamped casings be safely fireformed for use in an original 280 A.I. chamber with the 0.014" deeper headspace? Yes, they could be provided a technique is used to hold the SAAMI headstamped cartridge case head in firm contact with the bolt face during fireforming.

The two most common methods used are:
1) seat a bullet into the case neck so the ogive of the bullet is firmly jammed into the rifling so the bolt closes with some crush fit force on the casing being fireformed. The bullet being tightly jammed into the lands of the rifling will force the case head firmly against the bolt face. This will prevent the case web from stretching and thinning during fire forming. The powder charge used for this fireforming should be reduced ~15% below maximum book powder vharge weight for the bullet weight being fired, as jamming the bullet against the lands will increase pressure compared to loading the same bullet off the lands the common distance of 0.010" to 0.020";
2) expand the SAAMI headstamped case necks to .308 inner diameter using a case neck expanding mandrel. Then resize the case neck back down to accept the .284" diameter bullet, BUT leave enough of the .308 diameter neck to create a shoulder that butts against the chamber shoulder, and holds the case head in firm contact with the bolt face with the bolt closed on the casing. Then load a fireforming load using eirher Cream of Wheat, or load a bullet and fire the cartridge to blow the case shoulder forward the 0.014" to match the deeper 280 A.I. chamber headspace.

Once the cases have been fireformed, the case shoulders should have expanded forward 0.014" and can then be loaded normally for the useful life of the casings.

If you use fireforming method 2, I recommend annealing the case necks after fireforming... Because expanding the case necks up to .308 diameter and then resizing the necks back down to .284 will work harden the case necks a bunch.

 

[CBH Australia]

Thankyou @phorwath , that clears things up
I'm probably asking several questions in the thread.

Genuine interest in learning and reading all the time.

 

[antelopedundee]

The SAAMI 280 Ackley Improved is the only SAAMI adopted cartridge I know of that has Ackley in it's name and has a different headspace than PO Ackley's version would have.

I don't know if Tikka bolt faces are cut to different diameters for the 243, 270, 280, and 30-06 cartridge chamberings. But with the Tikka style extractor, there is some latitude in cartridge case head/rim diameters that will still allow reliable extraction of fired cartridges. I don't think a case head 0.005" smaller than the machined bolt face will cause any extraction problems.

I think your primary question is, can SAAMI 280 Ackley Improved headstamped casings be safely fireformed for use in an original 280 A.I. chamber with the 0.014" deeper headspace? Yes, they could be provided a technique is used to hold the SAAMI headstamped cartridge case head in firm contact with the bolt face during fireforming.

The two most common methods used are:
1) seat a bullet into the case neck so the ogive of the bullet is firmly jammed into the rifling so the bolt closes with some crush fit force on the casing being fireformed. The bullet being tightly jammed into the lands of the rifling will force the case head firmly against the bolt face. This will prevent the case web from stretching and thinning during fire forming. The powder charge used for this fireforming should be reduced ~15% below maximum book powder vharge weight for the bullet weight being fired, as jamming the bullet against the lands will increase pressure compared to loading the same bullet off the lands the common distance of 0.010" to 0.020";
2) expand the SAAMI headstamped case necks to .308 inner diameter using a case neck expanding mandrel. Then resize the case neck back down to accept the .284" diameter bullet, BUT leave enough of the .308 diameter neck to create a shoulder that butts against the chamber shoulder, and holds the case head in firm contact with the bolt face with the bolt closed on the casing. Then load a fireforming load using eirher Cream of Wheat, or load a bullet and fire the cartridge to blow the case shoulder forward the 0.014" to match the deeper 280 A.I. chamber headspace.

Once the cases have been fireformed, the case shoulders should have expanded forward 0.014" and can then be loaded normally for the useful life of the casings.

If you use fireforming method 2, I recommend annealing the case necks after fireforming... Because expanding the case necks up to .308 diameter and then resizing the necks back down to .284 will work harden the case necks a bunch.

I've always used method 1 to create 6.5-06AI cases, but some say that jamming a bullet accomplishes nothing. I don't agree and have never lost a case this way nor from web stretching upon repeated firings. Instead of COW in method 2 some say to use a fast pistol powder like bullseye up to maybe half a case full. Loud and messy. I'd bite the bullet and use a bullet.

 

[Pdvdh]

I've always used method 1 to create 6.5-06AI cases, but some say that jamming a bullet accomplishes nothing. I don't agree and have never lost a case this way nor from web stretching upon repeated firings. Instead of COW in method 2 some say to use a fast pistol powder like bullseye up to maybe half a case full. Loud and messy. I'd bite the bullet and use a bullet.

My experience using method 1 is it's best to use a long heavy bullet with good case neck tension on the bullet. Then jam the bullet hard into the lands to the point of firm bolt closure resistance. Then you're good to fireform.

But, if the bullet to case neck tension is insufficient, the case neck can shove/slide forward across the bullet when the firing pin strikes, and result in some case web stretching.

 

[antelopedundee]

My experience using method 1 is it's best to use a long heavy bullet with good case neck tension on the bullet. Then jam the bullet hard into the lands to the point of firm bolt closure resistance. Then you're good to fireform.

But, if the bullet to case neck tension is insufficient, the case neck can shove/slide forward across the bullet when the firing pin strikes, and result in some case web stretching.

If you put the smallest of smidgens of resizing wax on the case head it will prevent brass staining of the bolt face.

 

[bushwackr]

Ok so the gauges 4d sent me are correct. I got a go 280 ai saami, and a go 280 rem. So I use the saami as the go and 280 rem go as the no go. I have a saami chamber barrel

 

[Pdvdh]

Your goal is to cut a chamber in conformance with the SAAMI 280 Ackley Improved? Is that correct? If so, then you would want the go and no-go gauges for the SAAMI 280 Ackley Improved.

And if so, your statement about the 280 Rem go gauge is incorrect, IMO...

The 280 Remington go gauge is only useful if you wanted to cut a chamber for the original PO Ackley 280 A.I. The SAAMI 280 Remington go gauge would be the no-go gauge for the original 280 A.I. But not for the SAAMI 280 Ackley Improved cartridge.

The 280 Rem go gauge should have a headspace dimension 0.014" larger (greater / deeper) than the SAAMI 280 Ackley Improved go gauge. So it could never serve as a no-go gauge for the SAAMI 280 Ackley Improved cartridge.

I could be wrong, but since I'm one of few that understand the difference in headspace between the original and the SAAMI versions, I wouldn't bet against me.

Send me a PM if you'ld like, to discuss this further.

 

[antelopedundee]

Why didn't SAAMI just adopt the original Ackley Improved cartridge?

 

[Pdvdh]

Would have avoided a lot of confusion.

I think the answer us as simple as... Nosler didn't pursue that SAAMI adoption of the original Ackley cartridge.

I suppose only the Nosler guys know why? Their choice created a tremendous cluster of confusion. Many gunsmiths are confused too. So what are the chances of understanding by the average shooter and hunter.

 

[antelopedundee]

Do you happen to know which chamber that Redding offers die sets for? I would assume and maybe wrongly so that what they sell as .280Ackly Improved would be the SAAMI version.