280 Ackley Question

[Rubberduck]

I asked this on another forum but haven't gotten an answer yet so I figured I would try it here as well.

I have a Rem 700 that's chambered in the 280 Ackley (it's marked 280 Ack on the barrel). I have a Manson Go Gauge that's dated 9/13 that will chamber freely bare and barely close with a piece of Scotch tape on the back (+.002"). With a set of calipers, the shoulder location on the Go Gauge is the same measurement that Nosler lists in it's load book for its 280 Ackley (2.097").

Does that mean this rifle is chambered to the Nosler 280 Ackley rather than the original Ackley? I was under the impression that Nosler's version was shorter than the original and Nosler brass shouldn't be used in older Ackley chambers.

 

[Roughrice]

You need to measure with the .375 headspace comparator at which should read...2.132"-2.133".
Mine is 2022 Manson Go/Guage and reads 2.1325.
It sounds like Sammi if it reads "280 Ack Imp 40*"

 

[Roughrice]

Not the best way of measuring but...
I just measured mine... to the best of my ability with a caliper to the shoulder like you did.
I get 2.093-2.097... so it appears to be the same go/ guage

 

[Bob Wright]

Search here and find a plethora of discussions in other threads on this very question.

.280AI SAAMI vs. Original Chambering

I've got a .280AI that I bought used several years ago. It shoots awesome with loads using virgin Nosler 280AI brass. Because of all of the confusion regarding headspace on the old vs. SAAMI chambring, I have been a little reluctant to reload the once fired brass that is piling up. What do I do...

www.longrangehunting.com

 

[Roughrice]

If so, It should be fine to run Nosler ammo.
If you research really well... The only difference was the datam line at which it was measured. PO Ackley measured at a different point than the SAMMI... Hence the .014" difference.

NOTE: This is according to what I understand!
Someone else may chime in to correct if I'm wrong.

 

[Bob Wright]

You need to measure with the .375 headspace comparator at which should read...2.132"-2.133".
Mine is 2022 Manson Go/Guage and reads 2.1325.
It sounds like Sammi if it reads "280 Ack Imp 40*"

Here is the SAAMI cartridge drawing:
Edit to add my new brass measures 2.128. Fireformed will measure up to 2.132. I have a tight chamber....

 

[Roughrice]

Yep. Most of the 280 AI fired brass come out 2.135 ish from most factory SAMMI chamber that I've seen measured with .375 comparator.
Go figure.

 

[Roughrice]

I was merely giving a reference to what chamber he may have.

 

[Roughrice]

My Manson no-go is 2.1385 measured with same comparator.

 

[Rubberduck]

Thanks for the replies. Go Gauge reads 280 Ack Imp 40 Degree and with a .375 comparator I'm getting 2.1380" so I'm assuming it's chambered for the SAAMI/Nosler version. I didn't want to order Nosler brass and not be able to safely use it.

 

[snowcreekkennels]

I had one and wasn't sure about it and I sent three pieces of brass to Redding so I could get the right dies.

 

[Troutslayer2]

Search here and find a plethora of discussions in other threads on this very question.

.280AI SAAMI vs. Original Chambering

I've got a .280AI that I bought used several years ago. It shoots awesome with loads using virgin Nosler 280AI brass. Because of all of the confusion regarding headspace on the old vs. SAAMI chambring, I have been a little reluctant to reload the once fired brass that is piling up. What do I do...

www.longrangehunting.com

Hey I started that thread. This ended up being quite a disaster for me shooting nosler brass in the old ackley chamber. I was getting case head separation on the 2nd firing because it was growing way too much. Not sure what to say, I read everything on the internet then forgot it all. Now I've got a sammi chamber. I feel your pain if you do not know and in my experience I could not feel good about shooting the sammi brass.

 

[Roughrice]

I'm not a gunsmith but I know of a smith who chambered .014 longer than SAMMI thinking that his client would fire-form Rem 280 to the old Ackley and had case head separation problems from the get go.
From what I gathered... he used SAMMI reamer and went .014 deeper for the OP to fire-form 280 Rem brass.
TOTAL F'ING DISASTER!

 

[Bob Wright]

I'm not a gunsmith but I know of a smith who chambered .014 longer than SAMMI thinking that his client would fire-form Rem 280 to the old Ackley and had case head separation problems from the get go.
From what I gathered... he used SAMMI reamer and went .014 deeper for the OP to fire-form 280 Rem brass.
TOTAL F'ING DISASTER!

Omg!