Need help on fire forming 280AI brass

[MudRunner2005]

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.

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

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 is why I use a 75% charge, and seat the bullets into the lands for fire-forming to ensure the case head is firmly against the bolt face. It eliminates the case head separation issue, by allowing only the front of the case to stretch and form to the chamber properly, instead of the torsion it puts on the middle of the case. And also, incase your chamber is not 100% to spec (maybe a custom ordered reamer), then your cases still properly form to your chamber instead of having issues like just experienced with the cases not having the proper crush-fit for fire-forming.

 

[longbowelk]

This is why I use a 75% charge, and seat the bullets into the lands for fire-forming to ensure the case head is firmly against the bolt face. It eliminates the case head separation issue, by allowing only the front of the case to stretch and form to the chamber properly, instead of the torsion it puts on the middle of the case. And also, incase your chamber is not 100% to spec (maybe a custom ordered reamer), then your cases still properly form to your chamber instead of having issues like just experienced with the cases not having the proper crush-fit for fire-forming.

I understand the process you describe. I can do that. However, this rifle was built with an extended throat. A 162 gr Hornady bullet will barely be in the neck. I do have some 175 Sierra's that I may see if they will do better.
This was suppose to be the original P O Ackley but is now in actuality a P O Ackley wanna be that is sort of close but not exact. Therefore, I am encountering these problems.
If I load 75%, seat bullet into the lands I should get a case that is fully ready to take on acceptable AI loads and should not see any case damages. Keep in mind that due to the short mag and extended throat the bullet will be seated .2 off the lands and not .002. A 162 gr Hornady loaded to the lands shows COAL at 3.4585.
Maximum COAL in the mag is 3.258. That defys reloading logic.
I am no expert but the guy that built this rifle 1st should not use this action for a .280. But since he did he should have took into consideration the short mag and not put a deep throat on it. My gunsmith says he can take a thread out which should help but not completely.

 

[J E Custom]

I have never had that problem.(I know that does not help). You said you were going to talk to your smith, If so ask him if he used a SAMMI 280 AI Head space gauge.

This looks just like the problem the shooters were having with the new AI Chamber.
Dave Kiff Built the reamers for Nosler and they changed the reamer drawing without his knowledge

Some of his friends started having the same problem shooting 280 Rem in the new chamber.

When Nosler got the SAMMI standard approved with the changes, It became the standard and all reamers and head space gages have to be cut per these new dimensions by the reamer makers.

If he used a SAMMI 280 AI head space gauge or reamer and did not head space with a 280 REM head space gauge You have the new chamber and you will have to use the Nosler 280 AI ammo and brass.

If you don't understand PM me.

J E CUSTOM

 

[shortgrass]

The long throat sucks. But, when Bubba does his own 'gunsmithing' that's what happens. If your 'smith sets the barrel back one turn, mathematically that'll back the chamber up .083". He will then re-headspace the chamber. The "headspace" then can be set for the .004" crush on .280 Rem. ammo, as Ackley recommended. It's hard to set a barrel back more then one turn on a Mauser because most (not all) threaded tenons on Mausers have a "relief cut" or "kerf" cut next to the shoulder. Take more than one thread and that "kerf" gets pretty wide and the number of threads is reduced.

 

[MudRunner2005]

I agree with JE on this one... It sounds like you might have the longer new Nosler/SAAMI spec chamber. It's about .014" longer headspacing than the original P.O. design.

As for your last post, that sheds a lot more light on things. Yeah, sounds like that action should be chambered for SA cartridges only, like .308 Win.

You could always have it rebarreled to 7mm-08 AI... Your velocity wouldn't be quite the same, but you would definitely be able to take full advantage of the action & mag length, and the same primers and bullets. About the only things you'd have to sell or scrap would be the Retumbo and the .280 brass. The .280 AI is one of my favorite rounds, but this action is just not made for it. This is the route I would go for this particular action, if I was in your shoes. It might cost more money on your end, but I think you would enjoy the rifle more in the long-run.

 

[yawn]

This 280ai Saami thing is becoming farcical. It seems to get the blame for all and every problem with the 280ai.

Initially the claim was the new SAAMI spec was .014 shorter than the traditional and nosler cases were stretching in a traditional ackley chamber. Now the saami spec is longer causing case head separation with factory ammunition? Seriously?

Longboelk it seems you have a poor chambering job with excessive headspace or some other variant of the 280 improved. I would certainly have it checked. I have a hunch your are not alone and at least some of the controversy could be attributed to the same poor chambering.
Re the mystical .014 difference in the SAAMI spec
This is the best actual physical test I can find and their explanation as to why the chambers drawings show a difference is quite plausible. Also read the comments at the bottom.
https://gunsmithtalk.wordpress.com/2012/07/17/280-ackley-improved-emperical-headspace-test/

Nosler explain here in their FAQ , note the date , its well after all the controversy hit the internet. Also of note is the statement that" the decision was made to honor Mr. Ackley's original design intent by headspacing the cartridge such that standard 280 Remington ammunition would chamber with slight (.003"/.004") crush at the shoulder/neck intersection and fire form into the Ackley chamber without the need to seat the bullet into the rifling."
Nosler FAQ - The 280 Ackley Improved

Ill add Im just finishing up some actual physical measuring of my own. Initial results all in line with the gunsmithtalk findings. IE a chamber perfectly headspaced to P O Acklys .004 shorter than the parent case that is a perfect fit for noslers saami spec brass. If this .014 difference exists anywhere other than the chamber drawings Im yet to find it.

 

[longbowelk]

I agree with JE on this one... It sounds like you might have the longer new Nosler/SAAMI spec chamber. It's about .014" longer headspacing than the original P.O. design.

As for your last post, that sheds a lot more light on things. Yeah, sounds like that action should be chambered for SA cartridges only, like .308 Win.

You could always have it rebarreled to 7mm-08 AI... Your velocity wouldn't be quite the same, but you would definitely be able to take full advantage of the action & mag length, and the same primers and bullets. About the only things you'd have to sell or scrap would be the Retumbo and the .280 brass. The .280 AI is one of my favorite rounds, but this action is just not made for it. This is the route I would go for this particular action, if I was in your shoes. It might cost more money on your end, but I think you would enjoy the rifle more in the long-run.

That was one of my thoughts to rebarrel to the 7 08 or 7 08 AI. I have a Savage 11 in the 7 08 and really like it. I still had my heart set on the 280AI.
Before i do anything i am going to check the headspace to see what is the situation. As Short grass said, I need to see what "Bubba" has done. Then weigh my options.

 

[J E Custom]

It is really very simple.

If the bolt closes on a 280 rem go gauge, It is not chambered/Head spaced correctly.

J E CUSTOM

 

[shortgrass]

It is really very simple.

If the bolt closes on a 280 rem go gauge, It is not chambered/Head spaced correctly.

J E CUSTOM

Too simple, too simple! If we think about this harder we should certainly be able to over-complicate this! I mean,,,, it's only work that way for how long?

 

[longbowelk]

It is really very simple.

If the bolt closes on a 280 rem go gauge, It is not chambered/Head spaced correctly.

J E CUSTOM

Go Gage ordered last night, got confirmation it was shipped at 9:35pm last night. Those folks at MidwayUSA get with the program. I should know something soon. I do appreciate all the help on this matter...Thanks & stay tuned as I will post an update
PS: I should be "mad as hell" but I am not. I'm not real happy but on the positive side I have learned a ton of info in this process. Let the Saga continue...

 

[longbowelk]

This is why I use a 75% charge, and seat the bullets into the lands for fire-forming to ensure the case head is firmly against the bolt face. It eliminates the case head separation issue, by allowing only the front of the case to stretch and form to the chamber properly, instead of the torsion it puts on the middle of the case. And also, incase your chamber is not 100% to spec (maybe a custom ordered reamer), then your cases still properly form to your chamber instead of having issues like just experienced with the cases not having the proper crush-fit for fire-forming.

Mud:
Per your statement "I seat into the lands with light loads to ensure that my cases form with 100% correct headspace"
I know I have a headspace problem. While I am waiting on my go gage to ck my headspace I am going to try a 162 Hornady and/or a 175 Sierra if needed to see if it will fireform correctly without messing up the brass. I will make sure it is to the lands. My question is will the 75% powder charge get the projectile out of the barrel. You know I am having to use the heavier bullets to get to the lands and still be in the neck enough. A 139 won't even come close as it is too short. I went back and checked the brass on the lighter loads and I noticed that they even show a slight bulge in the case at the bottom. Bottom line is all the brass I have fired is going in the trash as I can not use them. If I can be successful with this next process I plan on making just enough to load AI and see if the rifle will shoot decent. If not I will go to plan B or C of rebarrel to 7 08AI. I still want and plan on a 280AI ...

 

[MudRunner2005]

Mud:
Per your statement "I seat into the lands with light loads to ensure that my cases form with 100% correct headspace"
I know I have a headspace problem. While I am waiting on my go gage to ck my headspace I am going to try a 162 Hornady and/or a 175 Sierra if needed to see if it will fireform correctly without messing up the brass. I will make sure it is to the lands. My question is will the 75% powder charge get the projectile out of the barrel. You know I am having to use the heavier bullets to get to the lands and still be in the neck enough. A 139 won't even come close as it is too short. I went back and checked the brass on the lighter loads and I noticed that they even show a slight bulge in the case at the bottom. Bottom line is all the brass I have fired is going in the trash as I can not use them. If I can be successful with this next process I plan on making just enough to load AI and see if the rifle will shoot decent. If not I will go to plan B or C of rebarrel to 7 08AI. I still want and plan on a 280AI ...

I use about 45 grains of Reloder 19 to form my .25-06 AI and .30-06 AI cases. So, I do not use the slow-burning powder to fire-form. A 75% charge of 7828 might cause some issues, so I'd use a faster powder, like RL19.

I think you should do a .280 AI on a blueprinted 700 long action. You'll be able to enjoy the 3.65"-3.70" mag length.

 

[shortgrass]

I agree with JE on this one... It sounds like you might have the longer new Nosler/SAAMI spec chamber. It's about .014" longer headspacing than the original P.O. design.


.

Actual gauging shows different. My 'personal' .280 Ackley headspaced with a SAAMI "GO" gauge. The bolt (stripped) will not close on the "GO" that has a piece of .002" thick steel shim stock stuck to the base of the gauge with a 'dab' of grease. The bolt WILL close with the "GO" gauge and a small piece of .001" steel shim stock stuck to the base of the gauge with a 'dab' of grease. When I use the .280 Remington "GO" gauge with a .002" thick piece of steel shim stock stuck to the base of the gauge with a 'dab' of grease the bolt will close on that same chamber, but I CAN FEEL THE INTERFERENCE FIT IN THE BOLT HANDLE. So, with the .280 Rem. "GO" gauge we have the .002" shim before I can feel the gauge in the chamber. We're still missing the .004" "crush" Ackley recommends. That makes for a total of .006" PASSED P.O Ackleys' specs. Now, add in the 'other' variable,,,, the brass. New brass will almost always be under-size. Say the new brass is .005" under. Add that to .006" that's already "out of Ackleys' specs" and you have a total of .011" excess space, with a .280 Rem. round in this SAAMI headspaced chamber, that can give you all kind of trouble. Before the .280AI was standardized chambers were cut many different ways by many different people. Some used a .280 Rem. "GO" gauge and depth mics, Some used a piece of brass. Some didn't bother to set the barrel back and just cut 'till the .280 Remington/7mm Rem. Express chamber "cleaned-up". To complicate matters, I have a JGS print that I received when I bought my .280 Remington Ackley Improved reamer in '95. It show the neck/shoulder junction being exactly .014" longer than the bolt face to neck/shoulder junction on the new SAAMI print. It shows the .280 Rem. AI to be .014" longer at the 3/8" diameter datum to the bolt face, too. Confusion? You bet! Now add in the differences in chamber reamers and gauges from maker to maker as there was no real standard, but more of an "interpretation" by the tool makers......... Conclusion,,,,,,,, know your chamber. When buying 'used' take nothing for granted!

 

[longbowelk]

Update: I loaded up a 162 gr Hornady with 45 gr IMR4350.
The bullet was to the lands. I took a measurement and it was 2.889 to the ogive. COAL was 3.4593 After firing, The case showed a slight ring at bottom. I need to back off the powder. However, I took some headspace measurements of the brass with my Hornady Headspace gauge.
I got 2.136 Some of my previous bullet fired cases that weren't cracked using the same 162 but not to the lands got the same 2.136
I read on another thread the Original Ackley was 2.144 & new Nosler is 2.13
Comparing mine to the original(what I am suppose to have) looks like I have .008 headspace which is where the problem is of why I can't fire factory ammo.
Any thoughts?