7 rem mag or 280 ack?

[ImBillT]

Unfortunately nothing was communicated to me. Finally another Smith asked me to start measuring from a chamber casting on one rifle, and the other, just see if fired brass would accept a new bullet.
After turning necks all pressures settled down at .004 clearance total.
The 280AI developed donuts which also had to be corrected because I could not seat above the donuts with ~150 gr cup and core or heavier. It was on me to figure out what I was dealing with. Lesson learned.

Sounds like a difficult time for sure.
You shouldn't need .004" clearance to alleviate pressure problems. That makes me suspect the donut was part of the issue. With less clearance your donuts were causing even bigger problems than normal. Just a guess. But .001" total. .0005" per side should be plenty of clearance with turned necks. You do need more than that for a "no turn" since the brass won't be perfect.

 

[Wachsmann]

We dont need to rob this guys thread, the explaination is long. In short they put a group of people together from around the state, i applied but wasnt selected, to look at redefining fair chase hunting with todays technology. The guys who got the ball rolling are from pocatello and they aren't fans of the longrange shooting when it comes to applying it to hunting. Ultimately they are aiming to limit the rangefinder capabilities to 600 yrds and scopes to a max of 9 power. I dont know what the outcome will be, im assuming it wont come out full force. We will probably end up with some limitations and gradually head, annually, to the full limitations.

I hope not. WOW. That is totally an ethics question for the individual and his on skill level. So much for Idaho being a free state. We just art to adopt all the California standards while we are at it. Maybe I won't stay in Idaho for retirement. That is really going to suck if they move to that. Maybe we need the industry to start lobbying instead since everything is moving towards this type of hunting. Why handicap someone just cause it's you personal ethics doesn't mean it's someone else's.

 

[AussieWriter]

A 7x57 and a 7mm Remington make a good pair though one covers much of the other.

I think I answered the OP's question here. I do also have a .280 Ackley and its a great rifle being a Model 70 Featherweight with exceptionally fancy piece of walnut, but it's also the 7mm I'd most likely rebarrel as the abovementioned 284's cover any 7mm need.
Another .30/06 loaded with 168gn TTSX's at 2850fps will cover the same ground and offer heavier weight bullets for larger game.

 

[ImBillT]

My point is simple, I operate to the pressure parameter of the parent case as designed regardless of what improvement I make to the cartridge. Below is my .338 Thor next to .338 Norma.

View attachment 637936

I do the same with my other wildcats.

But that principle doesn't apply to the SAAMI spec 280AI. It's pressure spec, is the pressure spec of the "parent case" (although that's not exactly the right word), because the "parent case" (as you're using the word) of the 280AI is NOT a 280Remington. The way you're using the word "parent case", the SAAMI 280AI is its own parent case. THATS WHY YOU CAN BUY FACTORY AMMO! That ammo is loaded with the 65ksi spec in mind! A SAAMI 280AI IS NOT an Ackley improved 280 Remington, and it IS NOT a wildcat cartridge. The SAAMI manual is available online. Look it up. The 280AI is listed. It's listed 65ksi. Your Thor is not listed. You cannot buy factory ammo for the 7x57AI, 243AI, 25-06AI, or 30-06AI because they are all wildcats. The SAAMI 280AI is not a wildcat. It has published pressure specifications. There is NO REASON to reference 280Rem pressure specification for the SAAMI 280AI.

Additionally, how do you test pressure when loading your 338 Thor?

 

[AussieWriter]

But that principle doesn't apply to the SAAMI spec 280AI. It's pressure spec, is the pressure spec of the "parent case" (although that's not exactly the right word), because the "parent case" (as you're using the word) of the 280AI is NOT a 280Remington. The way you're using the word "parent case", the SAAMI 280AI is its own parent case. THATS WHY YOU CAN BUY FACTORY AMMO! That ammo is loaded with the 65ksi spec in mind! A SAAMI 280AI IS NOT an Ackley improved 280 Remington, and it IS NOT a wildcat cartridge. The SAAMI manual is available online. Look it up. The 280AI is listed. It's listed 65ksi. Your Thor is not listed. You cannot buy factory ammo for the 7x57AI, 243AI, 25-06AI, or 30-06AI because they are all wildcats. The SAAMI 280AI is not a wildcat. It has published pressure specifications. There is NO REASON to reference 280Rem pressure specification for the SAAMI 280AI.

Additionally, how do you test pressure when loading your 338 Thor?

True. The .280 Remington also has a longer case which is still longer when fireformed in an Ackley chamber.

My Remington 280 Factory ammo measured around a .015" longer case than SAAMI spec's and reloading manual case length for the Ackley.

 

[FEENIX]

But that principle doesn't apply to the SAAMI spec 280AI. It's pressure spec, is the pressure spec of the "parent case" (although that's not exactly the right word), because the "parent case" (as you're using the word) of the 280AI is NOT a 280Remington. The way you're using the word "parent case", the SAAMI 280AI is its own parent case. THATS WHY YOU CAN BUY FACTORY AMMO! That ammo is loaded with the 65ksi spec in mind! A SAAMI 280AI IS NOT an Ackley improved 280 Remington, and it IS NOT a wildcat cartridge. The SAAMI manual is available online. Look it up. The 280AI is listed. It's listed 65ksi. Your Thor is not listed. You cannot buy factory ammo for the 7x57AI, 243AI, 25-06AI, or 30-06AI because they are all wildcats. The SAAMI 280AI is not a wildcat. It has published pressure specifications. There is NO REASON to reference 280Rem pressure specification for the SAAMI 280AI.

Additionally, how do you test pressure when loading your 338 Thor?

OMG! Here we go again. If you cannot understand my most straightforward point, I cannot help you there.

 

[ImBillT]

OMG! Here we go again. If you cannot understand my most straightforward point, I cannot help you there.

You're the one who is lacking understanding. Every clarification you've made continues to show that you do not understand.

Do you at least understand that factory 280AI ammunition on your local shelf is loaded to 65ksi and not 60ksi?

 

[ImBillT]

True. The .280 Remington also has a longer case which is still longer when fireformed in an Ackley chamber.

My Remington 280 Factory ammo measured around a .015" longer case than SAAMI spec's and reloading manual case length for the Ackley.

I'm honestly surprised you managed to chamber it unless you ran it through a SAAMI 280AI sizing die first. The neck/shoulder junction of the 280Rem is .018" longer than a SAAMI 280AI.

At only .004" longer, 7x64 Breneke brass is just perfect.

 

[FEENIX]

You're the one who is lacking understanding. Every clarification you've made continues to show that you do not understand.

You are entitled to the opinion. Ackley designed the improvement to allow the parent cartridge/ammo to be shot in the improved chambering, which is why I noted the parent case. Most of my friends who shoot the .280 AI chambering still fire-form .270 Win and .280 Rem brass.

 

[AussieWriter]

I'm honestly surprised you managed to chamber it unless you ran it through a SAAMI 280AI sizing die first. The neck/shoulder junction of the 280Rem is .018" longer than a SAAMI 280AI.

At only .004" longer, 7x64 Breneke brass is just perfect.

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.

 

[Deputy819]

Ed, let me help you:

 

[FEENIX]

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.

LL!

 

[FEENIX]

Ed, let me help you:

View attachment 641059

LL! Thanks, I needed that.

 

[ImBillT]

You are entitled to the opinion. Ackley designed the improvement to allow the parent cartridge/ammo to be shot in the improved chambering, which is why I noted the parent case. Most of my friends who shoot the .280 AI chambering still fire-form .270 Win and .280 Rem brass.

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.