Originally Posted by woods
I have the older Ackley chamber done by Hart when they rebarreled. I discovered the problem after I used some Nosler 280AI brass. The primers looked like this
wondering what was going on when IDbound clued me in with his post
and directed me to GunSmith talk about it
280 Ackley Improved Alert | GunsmithTalk
Now I just use 280 rem caliber brass and I don't have a problem. I still used the Nosler 280AI brass after it was fireformed with no problem but flattened primers like that are not something to repeat.
So according to all information that I have seen, the Nosler 280AI brass is made smaller to fit the new SAAMI specs with appropriate headspace. But that also means that Nosler 280AI brass will fit in either the new or the old chambers.
Nosler has loading data for other AI cases and they all match what in Sierra manual and since those manuals been out for a number of years that would be a good source for loading data. The 280AI in those manuals is bigger than the 280 case since the case was blown out and the Nosler 280AI brass is larger then those two case in earlier Nolser manual and 280AI in Sierra manual. Sierra/Nosler had case dia at the shoulder .450" and SAAMI spec is .454" and they lengthen the case body .007" and to the start of neck .005" so it has little more case capacity. they keep case length 2.525"
What Nosler did if you look at cases like 22-250,243,6rem,270,257,30-06 that have been used for the AI case dia at the shoulder has been .454/.455". Nolser change the dia from .450" to .454" to bring in more to the AI dia.
I'm sure die's were made to those two diagrams in earlier Nolser/Sierra manuals and I'm sure if they were different it would of been known.
there is also a 280 Improved which is listed in "THE HANDLOADER'S MANUAL OF CARTRIDGE CONVERSIONS" which is different also.
I'm looking at reloading manuasl that have those two prints of the 280AI and Nosler SAAMI Spec print and if your chamber was different you made of had something else.