Need help on fire forming 280AI brass

[shortgrass]

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?

You will not know anything for sure until the headspace gauge arrives. You can access the SAAMI web site at ; www.saami.org the Nosler version of the .280AI is shown there under "rifle chamber prints". Remember, the drawing at the top of the page is the cartridge, the one at the bottom is the chamber.

 

[MudRunner2005]

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?

If that's the case, then starting out with Nosler .280 AI brass might be the better option. Worth a shot.

 

[shortgrass]

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?

The bullet needs to be jammed into the lands, not just touching. I'd jam it .005-.010". Enough I'd have to 'lean' on the bolt handle to close it. If you still have a 'swell' at the head, it might be that the diameter of the chamber is over-sized (thank Bubba!). I'd not be buying any Nosler AI brass at $75+ until I gauged the chamber. Besides, Nosler AI brass is "out of stock" everywhere.

 

[MudRunner2005]

The bullet needs to be jammed into the lands, not just touching. I'd jam it .005-.010". Enough I'd have to 'lean' on the bolt handle to close it. If you still have a 'swell' at the head, it might be that the diameter of the chamber is over-sized (thank Bubba!). I'd not be buying any Nosler AI brass at $75+ until I gauged the chamber. Besides, Nosler AI brass is "out of stock" everywhere.

Yes, there needs to be resistance when you close the bolt on the loaded cartridge to ensure the case head is right up against the bolt face.

I also concur with the rest of your post. And agree that he needs to not spend the money on Nosler brass until you have that chamber measured for accuracy.

 

[longbowelk]

The bullet needs to be jammed into the lands, not just touching. I'd jam it .005-.010". Enough I'd have to 'lean' on the bolt handle to close it. If you still have a 'swell' at the head, it might be that the diameter of the chamber is over-sized (thank Bubba!). I'd not be buying any Nosler AI brass at $75+ until I gauged the chamber. Besides, Nosler AI brass is "out of stock" everywhere.

I will try the jam deal. But since 45 gr of powder was a little hot. Do you think 40 would be about right?

 

[longbowelk]

Yes, there needs to be resistance when you close the bolt on the loaded cartridge to ensure the case head is right up against the bolt face.

I also concur with the rest of your post. And agree that he needs to not spend the money on Nosler brass until you have that chamber measured for accuracy.

I forgot to mention, this bolt is not super smooth in closing or opening without anything in it. So, it is difficult to figure if the bullet is jammed. I have been jamming a bullet with no powder into the chamber. I leave it out a little, then jam it. Then I measure it for seating the regulars. So, I guess I should add a few thousands to get that good jam.

 

[MudRunner2005]

I will try the jam deal. But since 45 gr of powder was a little hot. Do you think 40 would be about right?

IMR 4350 is a pretty fast powder. It's several slots higher (faster) than RL17, so it's definitely a lot faster than RL19. I don't use a powder that fast for forming, so I can't really give you a yes or no on that. But I'd lean towards yes, since you're loading them into the lands.

 

[shortgrass]

The bolt on a Mauser should close smoothly and easily on an empty chamber. If it does not, it could be you have other problems, such as the locking abutments setting back in the receiver. I'd suggest getting that rifle to a gunsmith who is familiar with Mausers for close examination before firing it again. If the lug abutments are setting back that will give you an excessive headspace condition no matter what you do. It's also a safety issue.

 

[longbowelk]

The bolt on a Mauser should close smoothly and easily on an empty chamber. If it does not, it could be you have other problems, such as the locking abutments setting back in the receiver. I'd suggest getting that rifle to a gunsmith who is familiar with Mausers for close examination before firing it again. If the lug abutments are setting back that will give you an excessive headspace condition no matter what you do. It's also a safety issue.

I guess I need to find another gunsmith. At the time he was bore scoping it I didn't mention it to him and he worked the bolt but didn't say anything about it. He did tell me that he had built a lot of rifles with that action. When I first picked up the rifle from my FFL he told me the bolt wasn't functioning too smooth. Got to be something going on as the safety is hard to operate, too. Nothing like my Remington or Savage.

 

[longbowelk]

The bolt on a Mauser should close smoothly and easily on an empty chamber. If it does not, it could be you have other problems, such as the locking abutments setting back in the receiver. I'd suggest getting that rifle to a gunsmith who is familiar with Mausers for close examination before firing it again. If the lug abutments are setting back that will give you an excessive headspace condition no matter what you do. It's also a safety issue.

Update: I checked the bolt opening and closing last night during fireforming and it seems to be ok. I think it has loosened up since I first operated it. I really paid more attention to it and it is fine. I think the gun had set up a while and got a little stiff. Probably wouldn't hurt to try and clean the bolt. The safety is a real pain as no way it should be so hard to get on safety. Anyone can give me any advice on this would be helpful. This is the side safety and not the one on top that flips up and down.




As far as fireforming I shot 3 rounds, all 162 jammed into the lands. I seated the bullets just past the lands around .004. I felt the resistance in the bolt closing so I know they were in there.
I started at 40 grains of IMR4350, it showed possible slight bulge at base,
37.5 you could bearly make out the slightest indication of a bulge, finally, 35 grs all you could see was a brighter line around the base, no bulge
The headspace measurements were the same as before on 1st 2 @ 2.136
Last one(35) was at 2.135
The 35 grains looks to be the ticket for now.

 

[shortgrass]

The stock is probably interfering with the safety lever. My best guess without having the rifle in hand. As for the bulged cases, it sounds to me like the chamber diameter is oversized,,,,, not a good chambering job. Again, just a guess without having the rifle in hand. As "Bubba" built this 'thing', you need to have the rifle checked out by a competent gunsmith who is familar with the Mauser. When you find one, take him some fired brass along with the rifle for examination. Expect to pay for gauging and a chamber cast and possible test firing. This 'thing' has too many issues to be diagnosed on an interdnet forum.

 

[yawn]

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!

Defiantly one of the best posts Iv seen on the topic and thank you for the comparison of your chamber with the actual gauges , its a rare thing. It adds very well to the slowly growing body of information. If its not to much trouble would you be able give me the make, age and overall length of your 280 rem go gauge?

 

[TOM H]

Prior to SAAMI Spec 280AI both Sierra and Nosler had load data for 280 Ackley Improved and case were the same. Nosler manual # 4 1996 Kenny Jarrett gave little introduction for 280AI and there was comment from Nosler lab on how to fireform 280 case and how to eliminate case stretching in the web area,a cause of case head separation. They also mention " there is no industry standard maximum overall length for this cartridge. There is no established max pressure limit for the 280Improved. These load do no exceed SAAMI max average pressure for the standard 280 Rem (60,000PSI).

 

[shortgrass]

Defiantly one of the best posts Iv seen on the topic and thank you for the comparison of your chamber with the actual gauges , its a rare thing. It adds very well to the slowly growing body of information. If its not to much trouble would you be able give me the make, age and overall length of your 280 rem go gauge?

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.