Fire forming to Ackerly improved

David Swanson · Jul 18, 2005

I loaded a batch of new .257 brass with Nosler 100 gr. bullets and 30 gr. IMR 4895 to fireform my brass. I seated the bullets so they engaged the rifling. After I fired the first round, I had trouble pulling the bolt back, when I got it back the shell case would not eject from the bolt face. I had to pull the bolt from the rifle and "hammer" the shell case from the bolt face. The Ejector plunger left a considererable mark on the case as well there was blow back and cratering around the primer. I fired another round with same bullet/powder charge and got basically the same results.

I had some cases loaded with (excuse me, a Herters 87 gr. bullet), so I fired one of those. It seemed to fire alright and the case seemed to form correctly.

I'm not sure what I did wrong. 1) Do I have the bullets seated to far out, (and therefore "fix" the problem by simply reseating the bullets deeper). 2) Is the powder charge low low? 3) Could I have severly miss read my loading scale and over charged the cases? ( I am not a novice at reloading but I suppose that could have happened) I loaded all rounds individually, weighing the powder charge for each round.

Please help, I have over 500 rounds loaded to blow out the brass to Improved with either 30 or 33 gr. of IMR 4895.

fredj338 · Jul 18, 2005

Well you could dissect a round & weigh the charge, make sure it isn't an over load. I use a med. burner, starter load, for my .260AI & seat the bullet hard into the lands, no problems. I've fireformed w/o bullets before for my .404 jeffery also w/o problems (just to see if I could).

JD338 · Jul 18, 2005

David,

I just had a 280 AI made and went through the fire forming process.
I was advised by my gunsmith to load up my normal 280 Rem load with new brass to fire form to the AI chamber. Seating bullets into the lands is not necessary because the case is headspaced off the bottom of the neck.
At least in the case of the 280, max loads for the 280 Rem are starting loads for the 280 AI.
It is my understanding that a properly chambered AI will allow you to follow the above mentioned procedure. This is true for all AI cases.

In looking at Nosler guide #5. the 257 Roberts 100 gr load data for IMR 4895 (pg 156) shows start load of 33.0 grs and MAX load of 37.0 grs. The 257 AI load data for 100gr load (pg 162) shows start load of 40.5 grs and a MAX load of 44.5 grs of IMR 4895.

Just a thought, it could be that your FF loads are not generating enough pressure to form to the chamber so pressure getting behind the head of the case.

You might want to discuss this with your gunsmith but I think you need to up your charge and not seat bullets into the lands.

Hope this helps. Please let me know what you find out.

Regards,

JD338

David Swanson · Jul 19, 2005

JD338: Thanks for your input. The light load issue was a possibility. I will look into it with my gunsmith.

LoneStar · Jul 19, 2005

A properly-chambered AI doesn't need the bullet seated into the lands, but unfortunately too many are chambered incorrectly. If all the "gunsmith" does is run an AI reamer into a factory chamber, the headspace is automatically incorrect and seating the bullet into the lands is needed.

There is no good reason for there to be an overpressure with 30 grains of IMR4895 - the light load did not cause high pressure indications as this particualr powder is very forgiving of low-pressure loads. The first thing I would look at: was the correct powder used - make sure it wasn't IMR4198, and that the correct charge weight was thrown.

A max charge of 4198 might be okay with an 87-grain bullet but be an overcharge with a 100-grain bullet...I don't have my manuals handy right now.

41mag · Jul 19, 2005

I have two calibers in AI and have never seated bullets into the lands in order to fireform. I generally just load up standard cases just a bit over a mid load and shoot as normal. Heck in both the accuracy is almost just as good as the fireformed rounds. I have never had any pressure issues in either of them.

I would check the powder first, then if all is well with it I would try some using standard OAL's, and see if that didn't help. It won't take but a minute to set the bullets back some in order to clear the lands. Heck if it's only .050" it might make all the difference in the world.

If that still doesn't work I would talk to the smith and see what he allows on how the chamber was cut.

Savage99 · Jul 20, 2005

Don't fire anymore of that ammo as its too hot.

Take some apart and weigh the powder, check that the bullets are the right diameter etc.

You may have mixed up the powder too.

Be careful.

chundoo · Aug 9, 2005

PO Ackley advised against seating the bullets into the lands in his book. He said he'd seen guns blow up from this practice. He said to use a standard load in order to fireform. I have done this with a 6mm Rem AI and a 7x57 AI with good success.

As already stated, make sure the headspace is right and double check that all the components are correct.

2ndtimer · Aug 9, 2005

After pulling a bullet or two to verify the powder used and weight of the charge, I would consider seating a few of the rounds to more normal depth and try test firing them. If they extract and eject normally, it may have just been the anomoly of jamming the bullet into the lands. If it adequately fireforms your new cases, and extracts normally, then seat the rest of them to the same length and get it going. Let us know how it works.