7 rem mag or 280 ack?

[ImBillT]

You don't run factory ammo through a resizing die........lol.
It chambers to a slight contact fit, no issues. Just making the point that 280 ammo and specs has a longer case than a SAAMI 280 Ackley.

Well I was referring to brass, but the ammo must have been a little on the short side at the neck/shoulder junction, or your chamber a little on the long side. It's difficult if not impossible to chamber a round that is .018" long at the shoulder.

Nosler never intended you to fireform 280 Remington brass. A big part of them making it .018" short was probably so you'd have to buy their brass.

 

[FEENIX]

But that's not what a SAAMI 280AI is!!!!!

Nosler designed a cartridge very similar to an Ackley improved 280Rem, but not exactly, and they submitted it to SAAMI, and named it 280 Ackley Improved. But it is NOT the cartridge that you would get by Ackley improving a 280 Remington!!!! If you can close the bolt on an 280Remington in an SAAMI 280AI, it is very difficult, and it was never intended by Nosler for you to fireform at all. Even if it was, it is a SAAMI specified cartridge. Other Ackley Improved cartridges never received SAAMI specification.

Yes I know exactly what PO Ackley was doing. I have three of his books if not four. I own multiple AI'd cartridges beyond the 280AI. A SAAMI 280AI is not a true Ackley improved cartridge. The higher SAAMI pressure spec has absolutely nothing to do with the "improved" case shape.

You never told me how you're measuring pressure in your Thor. Are you measuring pressure in any other improved cases?

Below is from the actual SAAMI publication, and Hodgdon load data. SAAMI lists pressure in hundreds of PSI, so 650 for the 280AI is 65,000psi, and 600 for the 280Rem is 60,000psi. Hodgdon shows a few loads for the 280AI with pressures of 63,000psi. The highest pressure load that Hodgdon lists for the 280 Rem is 59,600 psi. The difference has absolutely nothing to do with being and "improved" cartridge. It has everything to do with the company that submitted specs to SAAMI choosing 65ksi.

Which part of people (most of whom are longtime wildcatters) still use .270 Win and .280 Rem brass in their SAAMI .280 AI chambering, you do not understand?

 

[CRP003]

ImBillT is correct and Feenix you are wrong.
You are not understanding the (AI SAAMI) and Petey isn't going to rescue you out of this one !

 

[FEENIX]

ImBillT is correct and Feenix you are wrong.

LL! I appreciate you settling it.

 

[ImBillT]

Which part of people (most of whom are longtime wildcatters) still use .270 Win and .280 Rem brass in their SAAMI .280 AI chambering, you do not understand?

Which part of the brass case having nothing to do with the pressure spec do you not understand? The pressure specification has zero to do with whether the brass came from a 270Win, or 30-06, or 280 Rem, or 7x64 Breneke. The pressure specs exist to tell the firearm manufacture how much pressure the action and barrel must be designed to handle. All 30-06 based brass cases will handle 65ksi equally well/poorly. Using 280 Rem or 30-06 brass instead of 280AI brass in your 280AI does not require reducing pressure. The brass case isn't the reason that a 280 Rem has a lower pressure spec than a 280AI and a 280 Rem case will handle 65ksi exactly as well as a 280AI case will.

Are you ever going to tell me how you measure pressure in your Thor?

 

[FEENIX]

Which part of the brass case having nothing to do with the pressure spec do you not understand? The pressure specification has zero to do with whether the brass came from a 270Win, or 30-06, or 280 Rem, or 7x64 Breneke. The pressure specs exist to tell the firearm manufacture how much pressure the action and barrel must be designed to handle. All 30-06 based brass cases will handle 65ksi equally well/poorly. Using 280 Rem or 30-06 brass instead of 280AI brass in your 280AI does not require reducing pressure. The brass case isn't the reason that a 280 Rem has a lower pressure spec than a 280AI and a 280 Rem case will handle 65ksi exactly as well as a 280AI case will.

Of course, all the actions can handle 65,000 PSI. Otherwise, that would suck.

Small arms ammunition pressure testing is used to establish standards for maximum average peak pressures of chamberings, as well as determining the safety of particular loads for the purposes of new load development. In metallic cartridges, peak pressure can vary based on propellant used, primers used, charge weight, projectile type, projectile seating depth, neck tension, chamber throat/lead parameters.
(https://en.wikipedia.org/wiki/Small_arms_ammunition_pressure_testing)

Are you ever going to tell me how you measure pressure in your Thor?

No! I will tell you, though, that my action can handle the pressure it generates.

 

[TonyRumore]

Must hit 2950+ with 180 class bullets.

Since no one here has a pressure test barrel, just do what they do, and run up the pressure until you hit 2950. Done.
Then be sure to post "no pressure signs" noted.

Tony