280AI won't chamber

[VLD Pilot]

2.513-2.525. Min to Max. Those are optimum sizes. 2.535 works fine. Beyond that I'd be trimming.

 

[shortgrass]

^^^^^^^^^^^Bad info! Maybe you can get away with it, others may not and get in pressure trouble.! Exceeding SAAMI cartridge max length is a no-no! Advising others to do so is being negligent. Te poor guy's having troubles enough with loading for the .280 A.I.

 

[VLD Pilot]

^^^^^^^^^^^Bad info! Maybe you can get away with it, others may not and get in pressure trouble.! Exceeding SAAMI cartridge max length is a no-no! Advising others to do so is being negligent.

Your correct. I should have said works fine for me. I'm not advising it but it works well for me. Problem with longer than 2.535 is, it won't chamber correctly. When tried, you wind up with what happened in his picture. Many .223 shooter exceed the max trim length by way too much and never encounter issues with pressure or chambering. Some cartridges don't have issues while some may

 

[Blackhawk]

These are Sammi specs and not the exact chamber specs as you would have in a perfect world.
without getting into stacked tolerance or machining tolerance variations what the SAMMI Specification drawing indicates is that your brass case length has a tolerance of .012" from 2.513 " - 2.525".
You are correct in your assumption that your trim to case length should be 2.513"however i myself would mean that dimension and trim my cases to a dimension of .2.518".
Remember SAMMI Specs are for use in a perfect world scenario but we both no that in a real world regarding tolerances there are established highs and lows and as long as they are held to that established dimension + or - are passable.
Example :
Now let's say for example your chamber spec is 3.000" + - .010" . Using this your chamber may measure 2.991" and still be usable.
So it is in the real world and SAMMI Specs are simply a given set of proven working tolerances.
A guide if you will.
Now go on line to the powder company's web sites in order to get some load data recipes.
However be mindful that most recipes given from powder manufacturers are for maximum powder levels. Back off at least 10 percent from these given recipes.
Hope This Helps!

 

[lancetkenyon]

I picked up a Christensen Ridgeline in 280 Ackley this year and about went crazy with the whole wildcat vs saami debate.

My experience with the two chambers debate has left me with the following conclusion: One of the following is true,
1. There is no difference between a Saami chamber and wildcat cat chamber like some have argued.
2. The tech at Christensen doesn't know *** he's talking about and I have a saami chamber.

either way I love the rifle and even more so love the cartridge.

#2, definitely. No question about it.

 

[VLD Pilot]

These are Sammi specs and not the exact chamber specs as you would have in a perfect world.
without getting into stacked tolerance or machining tolerance variations what the SAMMI Specification drawing indicates is that your brass case length has a tolerance of .012" from 2.513 " - 2.525".
You are correct in your assumption that your trim to case length should be 2.513"however i myself would mean that dimension and trim my cases to a dimension of .2.518".
Remember SAMMI Specs are for use in a perfect world scenario but we both no that in a real world regarding tolerances there are established highs and lows and as long as they are held to that established dimension + or - are passable.
Example :
Now let's say for example your chamber spec is 3.000" + - .010" . Using this your chamber may measure 2.991" and still be usable.
So it is in the real world and SAMMI Specs are simply a given set of proven working tolerances.
A guide if you will.
Now go on line to the powder company's web sites in order to get some load data recipes.
However be mindful that most recipes given from powder manufacturers are for maximum powder levels. Back off at least 10 percent from these given recipes.
Hope This Helps!

True but even max powder loads in load manuals are much, much lower than what's still safe to load in many cases. Hornady especially.

 

[Legionnaire]

#2, definitely. No question about it.

Same experience. I bought a second-hand Cooper 52. Called the company with the serial number to find out if was SAAMI. They said no, earlier wildcat. That didn't seem right to me given my measurements of fired brass, so I rented a set of SAAMI chamber gauges to check. Definitely SAAMI.

 

[Alibiiv]

I am working on getting my 280AI off the ground you might say. I've been fireforming Hornady 280 brass and doing a 2nd firing with midrange AI loads. Prior to my last session I was prepping the 1st fired rounds that yielded me the headspace of 2.116 to 2.118. I resized and primed them and prior to powder and bullet I checked each one to make sure they would chamber. All passed that test. Next I put the powder and 162 gr Hornady SPBT bullet in just off the lands about .020. Now comes the problem. All the rounds were successfully shot and yielded a final headspacing of 2.117 to 2.1175 except one. See picture below showing the loaded round that would not chamber next to a successfully 2nd fired casing. When measured with the Hornady headspace tool it still shows to be 2.116 where it started. I am not sure but it looks like a false shoulder may be showing. Also, the shoulder looks messed up . Is it possible that when I rammed the bullet in the brass, the die possibly caused the false shoulder or the sort of flattening of the shoulder? I am using the Redding 280AI dies along with the .014 Redding competition shell holder.

I am not sure about the shoulder angle on the brass. Here are some photos of what my brass looks like out of the .270 Ackley Improved. The two ought to look pretty much identical, only .007 thousandths difference. The unloaded casing has been fired, but not resized.

 

[DucNutz]

#2, definitely. No question about it.

I think that's most likely.

 

[longbowelk]

This is the original Ackley chamber. I had a choice and opted for the original. The dies are Redding along with a .014 competition shell holder that is supposed to make it work right. This is my first Ackley. I originally was going regular 280 and I was swayed on this site to go AI. I have reloaded for years. I am by no means any kind of expert. I've read some of these posts and there are some terms and words I'm not familiar with. The case length on the one that wont chamber is 2.615, it might have been 2.616 prior to trimming. I have reloaded the suspect case and it will chamber now.

I sincerely apologize, I misread my dial caliper as I had an anvil on one end . The correct length is 2.515 to 2.516.. this is in line with the Sierra manual..

 

[CTK]

I had a well known gunsmith chamber my 280ai "sammi" 14 thou too short. Nosler brass would not chamber. this was 5 years ago. Confusion still exists.

 

[shortgrass]

I have chambered many .280 A.I. in my shop over the past 30 yrs. First with the "Traditional" tool and method, then when Nosler made theirs SAAMI. I have both reamers and GO/N0-GO gauges for the Nosler (SAAMI). I have always used Acklys' method of gauging for the "Traditional", where the GO for the parent cartridge (In this case, the .280 Rem) becomes the NO-GO for the A.I. Funny thing, on a SAAMI chamber where the gauges were used and the head space was set @ GO+ .0015-.002 .280 Rem brass won't 'crush' in the chamber. Both reamers and the gauges were made by Manson (Loon Lake Precision when I bought the first one). I give my clients the option as to which they want. I have had zero problems fire forming Win .280 brass in the SAAMI chamber as long as I hard jam the bullet.

 

[shortgrass]

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

 

[CTK]

Someone smarter than me should figure out how to tell people what the hell the SAMMI dimensions are once and for all. I believe the die standard nomenclature is 280 Ack.Imp. for Sammi and 280 Ackley Improved 40 Degree for the old chamber.