280 Rem Ackley Imp 40 ?

[Fast1]

I've looked, looked , and looked. Trying to find the case capacity of the SAMMI SPEC. The one that is built on the current Nosler factory gun , factory load and there brass.
Also what dies to get from what manu , part #'s. Since there are more than 1 of these rounds' designed , floating around.

Thanks.

[Fast1]

What no answers yet .

[Elkbane]

Fast,
I'd call Redding and pose the question to them, but do some more reading before you do.

I did some reading on the subject last year when I was trying to choose between 280AI and a 7MM WSM and the last thing I read indicated that the initial confusion re' whether there is a difference between "2 versions" has now been solved. Apparently it was a matter of the reamer prints on the two had an APPARENT difference in headspace (base to shoulder), but it was later determined that they were the same - it's just that the measurement across the datum of the shoulder was taken at a different point on the shoulder on one print and the measurement was missing on the other one. At least that's the way I understood it.

Anyway, I went with the 7mm WSM so I quit studying it.
Here's a link for Redding part numbers: http://www.redding-reloading.com/ima...ng_catalog.pdf

Elkbane

There are some other anomolies between the 280AI and 280Rem cartridge diagrams - the diameter at web on 280R is .47 and 280AI its .4685. If you ignore this and assume they are really the same, the difference in case volume between 280AI and r80Rem, from base to shoulder/neck junction (the usable portion of the case) is 3.7%. based on outside diameters. If brass thickness is the same for the two, the inside case volume should differ by the same amount. SAAMI doesn't publish case volume....

[thomae]

Saami specs are out there:
http://www.saami.org/PubResources/CC...20Improved.pdf
http://www.saami.org/PubResources/CC...%20Express.pdf

However, as Elkbane said, SAAMI diagrams don't include case capacity. My guess as to the reason it is not included is because that variable depends on the trim length and the thickness of the brass.
You can get a rough idea by estimating the thickness of the brass and doing the math (as Elkbane did) to find the area inside the case.
Your best bet it to find someone with that cartridge and measure the case capacity yourself.
Best of luck.

[BillPa]

I've looked, looked , and looked. Trying to find the case capacity of the SAMMI SPEC. The one that is built on the current Nosler factory gun , factory load and there brass.
Also what dies to get from what manu , part #'s. Since there are more than 1 of these rounds' designed , floating around.

Thanks.

I can't say I've ever seen an official SAAMI capacity spec for any cartridge. One reason, there are two figures, "average" and "effective". The "Standard" average total internal capacity. The "effective" capacity depends on the bullet and it's seating depth which subtracts form the actual internal capacity. The figure I have for the "average" Ackley 280 Imp-40 is 70.135 gr/H20. I would assume the SAMMI (Nosler) would be +/- less then a grain, but the only real way is to actually measure it.

And yes, there is a debate if the Nosler version and the old tired and true Ackley are the same or not. Some say yes, its .014" shorter while others claim they're the same, the difference is only how the two are being measured.

Dies? I can't help you out there, I've been using the same RCBS set I bought in 1978!

Bill

[Fast1]

Thanks' guys for the info. Never thought of going to SAMMIs web site. Just bookmarked it.

[Werewolf]

I am currently using a set of Lee 280AI limited production dies. I have been getting good results so far and good hunting grade accuracy, but I haven't really tried to work up a real accuracy load yet. I paid about $60 for the dies to get started and haven't needed to upgrade yet.

My barrel is a current manufacture by McGowen.

[jibben]

280 rem 68.221
280AI 70.135