Need help on fire forming 280AI brass

[longbowelk]

Thanks to all for the info. I need to shoot some loaded 280 rounds and see where I am at on this. I researched the fireforming prior to rifle purchase and thought it would be an easier process.

 

[wwbrown]

The 280 Ackley is headspaced different from most of the other Ackley's like I said in the earlier reply the shoulder is not just blown out but blown forward, where as most Ackley's just blow the shoulder forward. When headspacing the traditional Ackley the go gauge for the parent cartridge becomes the nogo gauge for the Ackely. When chambering non-fireformed parent brass you get a slight crush fit on the brass this is where the slight resistance comes when closing the bolt.

When I chamber a traditional Ackley and don't have go gauges specifically made for the Ackley I cut the chamber 0.004" short of the go gauge of the parent cartridge. When I order a reamer for an Ackley I just get a go gauge cut for that chamber then I can chamber normally.

For the 280 AI the shoulder is blown forward so you don't get a crush on the shoulder so either you start out with 30-06 brass and form a false shoulder by necking a portion of the 30-06 to 280 leaving the rest of the neck at original diameter. The portion of the neck at original diameter keeps the brass from moving forward when fired or possibly from the firing pin moving the brass forward when hitting the primer. Without the false shoulder you can seat the bullet long so it engages the rifling hard which usually keeps the brass pushed back when the firing pin hits.

Forming and fore forming brass for the original 280 AI is much like forming brass for the 6 mm Dasher because the Dasher shoulder is blown out and forward of the parent (6 mm BR) the same as the 280 AI. If you start with 280 brass you can run an 30 cal expander opening the neck up and then following up with by using your 280 AI die to form the false shoulder like I have when I go with the 30-06 brass, this is a very common way for 6mm Dasher brass forming.

Shortgrasss, I guess I have not answered your question re: resistance when closing the bolt on my 280 AI when fireforming brass and I did not since there is no interference between shoulder and the chamber due to using the go gauge as a no go gauge.

This is about I have to say on this subject, I have gotten into arguments on the chambering and fireforming brass for the 280 AI on other forums when people assume the 280 AI has the shoulder blown out and not moved forward.

Have a good day all!

 

[hydehunter]

dumb question? why not use Hornaday 280ai brass and go from there?

 

[J E Custom]

Thanks to all for the info. I need to shoot some loaded 280 rounds and see where I am at on this. I researched the fireforming prior to rifle purchase and thought it would be an easier process.

It is very easy if you have the original Ackley 280 chamber. If you have the "New" AI chamber, I recommend using the Nosler ammo/brass only.

All you need to do is buy/load some standard 280 Rem ammo and shoot it. the AI version is slightly larger than the 280, so the standard loads are fine to fire form. once you fire form, you can work up
the powder charge to near max.

If you load the 280 for fire forming, like everyone says, use the middle load listed on the 280 load
data.

Lots of people use the cornmeal method to fire form, but after firing the brass it still needs more forming so you end up firing twice to get the brass to fit the chamber well.

When I set up a 280 AI, I head space minus .004 off the head space gauge (Shorter)to have some resistance when closing the bolt on factory 280 Ammo. this holds the case firmly in the chamber and does a great job of forming the brass without stretching the brass shortening its life.

As mentioned, fire forming this way is known to be very accurate and most people hunt while fire forming to the AI version.

Don't over think it just enjoy the AI, It is one of the best.

J E CUSTOM

 

[TOM H]

Yes, I did try the Bullseye. I thought maybe the Unique might do better since it was listed as faster powder than the Bullseye plus most have stated they used the Unique. The only case that I have that was formed properly using a parent .280 cartridge is one that the seller gave me when I bought the rifle. I have been using it as a guide to compare my fire forming brass.

Since you have fired case from that chamber, how does that case compare to Sierra 280AI case they use in manual? I know Nosler had that same case in their manual prior to SAAMI spec 280AI

The big debate about was how Ackley chamber vs SAAMI spec, but I don't think anyone had a case to measure.

 

[MudRunner2005]

dumb question? why not use Hornaday 280ai brass and go from there?

Why? Well, for starters, because Hornady doesn't make .280 AI brass. And secondly, as we have discussed in this thread, the Nosler/SAAMI spec is not the same headspacing as the original P.O. Ackley chambering...Therefore, the Nosler brass would still need to be fire-formed to his chamber.

 

[shortgrass]

I happen to have chamber prints right in front of me! JECustom is correct don't over think this,, it's just too easy. Forget all the malarkey, it's straight forward load .280 Rem ammo and shoot it in the Ackley chamber. Now you have .280 Ackley Improved cases to reload.

 

[longbowelk]

I happen to have chamber prints right in front of me! JECustom is correct don't over think this,, it's just too easy. Forget all the malarkey, it's straight forward load .280 Rem ammo and shoot it in the Ackley chamber. Now you have .280 Ackley Improved cases to reload.

I believe you are right. I plan to do just that, reload and shoot some .280 Rem soon and will post the results.
Thanks...

 

[longbowelk]

Fireform update;
Yesterday, I fired some mid loaded reloads along with some factory loaded Hornady
Superperformance 139SST. These kicked like a mule. My reloads were like a .22
I did not realize until this morning as I was checking the headspace on these that these factory loads had blown the cases up. See pic. I had read somewhere that Ackley made this wildcat so if you ran out of AI loads you could fall back on regular .280. I will be taking this to my gunsmith but I thought I would post this to see if someone could maybe enlighten me. I'm thinking this gun has some headspace issues.

 

[shortgrass]

Did your .280 Rem. loads not have a 'crush' fit in the AI chamber?

 

[longbowelk]

I didn't feel any abnormal resistance. They seemed to chamber with no problem. I have experienced what you are talking about with a 7mm08 that I did some reloads with. some of them the bolt was hard to close so I had to seat the bullet a little deeper. I just figured that any factory load would do the job. These were the cheapest so that is what I got. As stated these loads kicked big time. These must be the hottest .280 load available. This gun was built by an individual. He used a Clymer reamer that has a tapered the throat. I have 3 different posts on this gun. 1st I thought the throat/chamber was burned out. The gunsmith told me the throat was tapered but the barrel was in good shape. The magazine is to0 short for the chamber/throat as in order to reach the lands the bullet is too long to fit the mag so I had to single feed those. The 139 factories are almost 1/4 inch from the lands. However, they still shot a 1" group. After having all these problems I would never build a .280AI with this action/magazine. This is more made for the .308 cartridge and its siblings.

 

[longbowelk]

The action is ZBRO JOVKA BRNO,A.S.VZ.24
My gunsmith said they used to buy these in bunches and build rifles. At the time of that comment I did not realize the mag was so short.

 

[shortgrass]

The VZ24 has a mag that's too short for magazine feed. The .280 Rem. rounds should NOT chamber easily. You should have to apply moderate pressure to the bolt handle to completely close the bolt. When fire forming to Ackley Improved the parent cartridge (in this case .280 Rem) should be "trapped" between the bolt face and the neck/shoulder junction in the chamber. It should take some effort to close the bolt. If this condition is not met, you will have problems like you pictured. I hope your 'gunsmith' can show you better than I can explain it.

 

[shortgrass]

The VZ24 was originally chambered for the 7mm X 57mm or 8mm X 57mm Mauser cartridges. .308 class cartridges work OK when rebarreled for such. So does the 6.5 X 55 Swedish Mauser cartridge. The .284 and wildcats based off of that case can be made to work. The .30/06 and others of lesser diameter on the /06 case work unless you insist on those long VLD bullets. In short, about any cartridge with a OAL of 3.300" can be used. You need to stay within the limitations of the steel and heat treatment of the action, though. My 6mmRem. AI is built on a VZ24.. The VZ24 is a std. length Mauser '98. I have several classic custom rifles built on other std. length Mauser 98s.