Thread: Fire forming 270 to 280ai

thats a weird place to break.... but I guess asking that amount of brass movement HAS to come from somewhere.
heavy walled GI 30/06 brass perhaps (if it even exists anymore)??
I would be wary of what didnt break and using paperclip feeler guage vigourously to check.

also it may just be trick of light ,but it looks like you stopped short of running .30 cal expander completely into case??? maybe that didnt give you a firm enough shoulder??? never tried this caper myself,just pointing out what my eyes seeing on the middle case in photo.

Gun works has 280ai brass I just ordered more for mine

Greetings @Trav-6mmrem,
That did not go to plan. The cases did form for @sneeze but not for you. So what was different. Clearly the false shoulder did not do the job. Looking at the photo's the middle case in the photo on the left does not look as though the expander button has gone all the way through the neck which would have deprived the false shoulder of some support. There seems to be some difference in the neck lengths in the photo on the right which you may wish to measure. This could indicate that the problem was with some cases and not others. You don't say if you seated the projectiles hard into the rifling which would give more support. Necking up to a larger dia, like .338, would also be an option. R22 is a slow powder and a faster powder may help. Don't worry about a donut forming as the .280 is longer to the base of the neck than the .270 which will prevent this.
You said in an earlier post you wanted to further your handloading capabilities. This has been a steep learning curve but certainly has delivered.
Regards Grandpamac.

Probably bad Winchester brass as well. Their quality has gone to the dogs, suspect their annealing process and material quality is to blame.

PPU much better!

Did you neck anneal before doing this? It might be that trying this without neck annealing shared the stretching along the whole case length rather than just the neck shoulder where you want it to happen. Even with dodgy brass, neck annealing should help.

I have Norma 280 AI brass availible

It is longer than using 30-06 brass etc

Originally Posted by grandpamac

Greetings @Trav-6mmrem,
Don't worry about a donut forming as the .280 is longer to the base of the neck than the .270 which will prevent this.

Regards Grandpamac.

While shifting the original neck shoulder junction to the new shoulder might takeaway the initial risk ,should the shoulder brass be thicker than the original neck, steep shoulders have a higher propensity for donuts to form. Iv had them form after one firing in an early lot of nosler 280ai factory brass while latter batches have not. Iv also had to deal with them in factory norma 6.5x284 brass. While it isn't that common, its very easy to keep an eye so I would say ignore donuts at your peril. I have had success preventing it by neck turning with a 40 deg cutter and nipping a few thou into the shoulder.

@Trav-6mmrem Which brand of die are you using for your final resizing? Reason I ask is I have a similar rifle and have bought 4 boxes of factory ammo and am scouting around for a set of dies so as to be able to reload in due course.

That endeavor has brought to my attention the fact that Lee and Redding have sizing dies out there that they say are not to be used on SAAMI spec'd chambers as they wont push the shoulder back enough.

I bought a set of rcbs 280ai dies, the 280 improved 40° won't work in my Sammi spec chamber. Gun works had them in stock

Originally Posted by Trav-6mmrem

I bought a set of rcbs 280ai dies, the 280 improved 40° won't work in my Sammi spec chamber. Gun works had them in stock

Have you tried them and found an issue or are you going off other information?

No issue, the 280ai dies work fine. The info on line says the Sammi specs are 14 thou shorter shoulder compared to original ackley specs, this is coming from the redding website. My kimber being a new factory rifle will have the Sammi specs

Originally Posted by Trav-6mmrem

No issue, the 280ai dies work fine. The info on line says the Sammi specs are 14 thou shorter shoulder compared to original ackley specs, this is coming from the redding website. My kimber being a new factory rifle will have the Sammi specs

OK ta. Iv been down this rabbit hole for 15 years or so and keep my ear to the ground for someone that might have some actual physical evidence of the mystical 14 thou difference. After gauging quite a few chambers and measuring brass I'm yet to find any at all
If your interested there's some good reading here. https://gunsmithtalk.wordpress.com/2...mproved-alert/ These guys were early to the party with the warning regarding the difference. They copped some flak so built both the traditional and the SAAMI chambers to show the difference but actually found there was no difference at all. https://gunsmithtalk.wordpress.com/2...eadspace-test/

Sooo, I should be able to use a Lee die set designed for the "original ackley cartridge" and it will be fine for sizing brass in my saami spec chamber.

I have been able to determine the amount of shoulder set back needed by chambering my fired cases and comparing the difference between the ones that allow the bolt to close with no resistance vs the ones that don't.

Using this number I should be able to safely determine if my brass is indeed sized correctly?

Tell me if I'm missing something

I have a couple of hundred once fire 270 cases if you want practice ones