Need help on fire forming 280AI brass

[TOM H]

Jarrett rifles still chamber and sell ammo for the280 Ackley Improved.

Kenny Jarrett's Pet Calibers | Jarrett Rifles

 

[shortgrass]

longbow, remember to remove the firing pin assembly when you use your new gauge to check the headspace. Removing the firing pin assembly is always a good idea when figuring out "jam", too.

 

[longbowelk]

longbow, remember to remove the firing pin assembly when you use your new gauge to check the headspace. Removing the firing pin assembly is always a good idea when figuring out "jam", too.

Got my gauge today so I will be cking the headspace. Hopefully, I can get the firing pin out. I'll ck youtube for a video.

 

[longbowelk]

Shortgrass:
I went ahead this morning before I got my gage and loaded up a 280AI load using the last fireformed brass that was formed with the 35 grains of powder, 162 bullet jammed. I am going to post the pic now and repost the measurements I took on it before shooting, after shooting, and beside it is a 280 unfired brass. I will post the measurements but you will see the black marks where I took the measurements to see if any change etc.

 

[longbowelk]

Here is the pic. I will post the measurements soon.

 

[longbowelk]

For what it's worth. Here are the measurements I took with a dial caliper. The four lines are where I took them. Starting at bottom and going up. On the unfired 280: .463, .463, .462, .460...the Fireformed case before firing as 280AI, .4635, .466, .466, .464...same case fired as 280AI, .4635, .469, .467, .465
Last firing using 162 bullet at 2.881 to ogive (approx. .008 off lands using 48 gr of IMR 4350).
Will post headspace next once I get the numbers.

 

[DocDoc]

Longbo
It looks like a bad chambering job? Seems like there is almost a reverse taper part way up.

 

[yawn]

The .280 Rem gauges were made by Forster and the "GO" gauge has 2.100" etched on it. I bought this gauge set right around 1994. I'll be fitting another barrel in 280AI (Nosler) to a Wby Vanguard this next week and will be making measurements both ways as I do (with the .280 Rem "GO" and depth mics, and with the SAAMI .280AI "GO" and depth mics) and will report back, on this thread, my findings.

Thanks again. I have the same gauge be it much later vintage. I wonder how they would compare? In My cooper 280ai the bolt will not close completely on the gauge. Im unable to find SAAMi spec 280ai gauges in this part of the world so Ill have to import to complete the measuring but I can say that nosler SAAMI spec brass chambers sweetly and the fired cases measure within .001 of the unfired in terms of headspace. Cooper Arms have told me they chamber to traditional Ackley and the gaugeing indicates they are correct.

 

[muhles]

fireforming brass for an ar 7.62 x 39 blowing it out to 40 cal 10 mm I have to set the brass on the bolt where the extractor hold it firmly aganst the bolt to fire it .this brass will just slide down the barrel if the ejector doesn't hold it on the bolt .that should take care of the primer problem and make the head space problem go away. it takes a little bit more effort to lock the brass on the bolt before you close it but it solves lots of problems. I fire form my loads with 13 grains of red dot and a patch with 12 # 6 shot in it.

 

[shortgrass]

Yawn, I found the same thing when I headspaced the barrel on the Vanguard. I can feel .280 Rem. brass crush when closing the bolt, but not as much of a crush as I'd like. I've got a coulple of different head stamps of .280 Rem brass I tried this with. The Hornaday has more resistance than the Win. The difference in brass manufacture. I have no Norma or Nosler .280 Rem. brass to try at this time.

 

[yawn]

Shortgrass that's inline with what Iv seen with the chambers Iv gauged.
Iv followed the SAAMI vs traditional debate for some years mostly because I simply wasnt seeing any physical evidence of the SAAMI chamber being .014 shorter than the the traditional discussed in threads such as this one.
http://www.longrangehunting.com/forums/f28/280-ai-controversy-explained-118623/

Thanks for taking the time to post your findings.