280 ai question

[Kbaker657]

Alright for curiosity does anyone have any new nosler 280 ai Brass and a headspace Gauge. I have some what of a "bastard" 280 ai and I was curious what new brass measures in comparison to fired brass from my rifle. If it matters I have the hornady headspace gauge set and I think the case should be measured with a .375 insert in the gauge. Thanks for any help

 

[raz175]

These are the measurements I got recently while working up a load for a Christensen Arms 280 AI. Using the Hornady .375 comparator;
Manson go gauge- 2.1335
Unfired Nosler 280 AI brass- 2.1335
Once fired Nosler 280 AI brass - 2.1345
Of course this is with my comparator, yours might not be the exact same dimension and can alter these numbers. Hope this helps.

 

[Kbaker657]

Thanks raz I pm'ed you

 

[Kbaker657]

A piece of fired brass from my rifle measures 2.125

 

[cdherman]

A piece of fired brass from my rifle measures 2.125

I fear you are correct about the bastard part. You seem to have either a different shoulder angle, or its set much shorter. Probably the former. Can you chamber standard 280 cartridges?

Alternatively, the variation in comparators could be an issue. Measuring unfired nosler 280 AI brass with my .375 insert, I get 2.135 I have a dial caliper and its zero'd. This could also account for variation from user to user......

 

[Kbaker657]

I can chamber standard 280 rounds but it is very hard to close the bolt. Harder than normal in an ackley. As far as the discrepancy between gauges and calipers I have wondered that my self.

 

[TOM H]

This is spec 280AI
http://members.saami.org/ManualsStds/CC_Drawings/Rifle/280 Ackley Improved.pdf

 

[Kbaker657]

This is spec 280AI
http://members.saami.org/ManualsStds/CC_Drawings/Rifle/280 Ackley Improved.pdf

Thanks Tom that's what I have run into. My head space is basically 15 thousandths shorter than minimum

 

[TOM H]

Thanks Tom that's what I have run into. My head space is basically 15 thousandths shorter than minimum

I have spec 280AI and use Nosler brass for that. I also have 280AI that was build before spec 280AI and I just fireform using 280 brass. Before Spec 280AI, Nolser and Sierra had loading data for 280AI which may be close to what you have. It's called 280 Rem Ackley Improved. this might help

http://www.redding-reloading.com/tech-line-a-tips-faqs/133-280-changes