Ackley question

[Milehighshooter]

Last year when I fired this gun for the first time, I got mostly good results. But I also had 3 cases totally rupture just above the head.

Today I went to the range, with some factory ammo, as well as hand loads (both in standard configuration) but with the bullets seated VERY long and into the lands, or close to it.

My question, is my suspicion correct that some garage hack smith just ran an Ackley reamer into the chamber, without setting the barrel back?

 

[Milehighshooter]

Pictures go:
Factory 257R
Factory 257R fired in my gun
Handloaded 257R with bullets jammed into the lands.

The longer base to shoulder, as well as the primer not being blown out, are my areas of concern

 

[Mekaniks]

So obvious high pressure....

I would start by measuring the distance to the lands, and hand loading new brass at the minimum recommended loading, for fireforming cases a long way off the lands.
Then take the fired brass and and start working loads up slowly watching for pressure signs and decreasing the distance to lands until you are satisfied.
If you can’t get the velocity or accuracy you should get desire without pressure signs, then worry about the barrel.
Who knows you may find a sweet spot that makes it real shooter. If not I have found handloafing and shooting to be good therapy

 

[Milehighshooter]

I don't think it is high pressure, I think it is excessive headspace. The middle picture of the bases, the backed out primer, is a factory load. The bottom picture, is my handloads jammed into the lands so that the brass doesn't move when firing. I think what is happening, from reading about AI, on the factory with insufficient headspace, is the firing pin is actually moving the cartridge forward as it ignites, so the case expands in both directions.


Sorry***
Forgot to say the ruptured cases were also factory loads NOT hand loads. Hornady Superformance. The other factory is Hornady +p

 

[Mekaniks]

I don't think it is high pressure, I think it is excessive headspace. The middle picture of the bases, the backed out primer, is a factory load. The bottom picture, is my handloads jammed into the lands so that the brass doesn't move when firing. I think what is happening, from reading about AI, on the factory with insufficient headspace, is the firing pin is actually moving the cartridge forward as it ignites, so the case expands in both directions.

Wow have a gunsmith check the headspace.....

 

[mdwest]

If you think its a headspace issue, I'd recommend renting some go / no-go gauges ($8 from 4D Reamers) and checking it out..

If your bolt closes on the go gauge, but wont close on the no-go, your headspace is fine...

If your bolt doesnt close on the go gauge or does close on the no-go.. you have a headspace problem..

 

[Pheroze]

Just eyeballing in the picture where the bases are lined up, the shoulder on those fired case looks like it went a long way forward. If you have a Willis Headspace gauge, or similar, it would be interesting to know how much that shoulder moved.

Also, if the brass is ok after the first firing maybe resize to just bump the shoulder back a couple of thou' would essentially fireform the brass?

Good luck with this problem.

 

[Hogpatrol]

What the others posted about headspace but if you loaded long to push the case against the bolt face, you should be OK. I would use another brand of brass. Hornady isn't the greatest stuff. From this chair, compared to the good stuff like Norma, Lapua and Peterson, there's no comparison. My experience is Norma is relatively softer and good for fireforming, Lapua next.

Edit: Why do the necks look all different diameters? Optical illusion? Can you check them and post the sizes of each?

 

[Heeler75]

First and foremost is I'd do a chamber cast and get dimensions so I could figure out exactly what I have and go from there. Did you buy it assuming it was a standard 257R?

Yes, it looks like someone AI'd that chamber and didn't set the barrel back. If done correctly (AI process) the bolt should close a little bit harder on factory ammo as the neck/shoulder junction is a little further forward. That's what allows the fireforming process to work. Also, the necks are a bit shorter on a case that has been AI'd. From your pictures, the necks are the same length.

 

[Milehighshooter]

First and foremost is I'd do a chamber cast and get dimensions so I could figure out exactly what I have and go from there. Did you buy it assuming it was a standard 257R?

Yes, it looks like someone AI'd that chamber and didn't set the barrel back. If done correctly (AI process) the bolt should close a little bit harder on factory ammo as the neck/shoulder junction is a little further forward. That's what allows the fireforming process to work. Also, the necks are a bit shorter on a case that has been AI'd. From your pictures, the necks are the same length.

That is what I am thinking. Factory ammo closes like, well, factory ammo, no resistance at all. My fire forming loads DID close hard, and seemed to have formed properly. The stuff I did myself was WW +P brass and seems to have worked as intended. I'll have to see what they do with the Lee AI dies. Might end up having to just hand load for forming, possibly send off a fired case to get dies made.

 

[Milehighshooter]

What the others posted about headspace but if you loaded long to push the case against the bolt face, you should be OK. I would use another brand of brass. Hornady isn't the greatest stuff. From this chair, compared to the good stuff like Norma, Lapua and Peterson, there's no comparison. My experience is Norma is relatively softer and good for fireforming, Lapua next.

Edit: Why do the necks look all different diameters? Optical illusion? Can you check them and post the sizes of each?

The Hornady was factory ammo. The WW was formed with my handload with the bullet jammed. That seems to have worked just fine. I think I have another 40 or so WW cases that have been FL sized for 257 R, and I just need to repeat the process from yesterday, seating out into the lands to hold the base against the bolt face. Hornady was the only 257 I could find at the time. I have some Winchester factory loads, but they are just as short so I think I'd run into the same problem. I'll probably just sell those off and go hand load formed from here out.

And yes I think its just an optical illusion from the camera

 

[fourfive8]

Let's see- head separation/rupture, backed out primers and possibly other signs of pressure and/or serious headspace problems. If I'm not mistaken, an "Ackley" chamber should have the same headspace length (bolt face to datum ring length) as the parent cartridge. That should allow the firing of standard parent cartridge to form to "Ackley" profile. You should not have to fireform a case by jamming a jacketed bullet into the lands (that's just asking for pressure spikes and problems). Some do fire forming by using a slightly lower pressure load and jamming a cast bullet into the lands.

I would have the headspace checked and corrected if needed... which I'm fairly certain is needed. Also, IMO, there is nothing wrong with Hornady brass and it is usually equal to or better on average than either WW or Rem.

 

[450 Dakota]

It might be a little on the loose side but the real question is how does it do once cases are fire formed. If your splitting cases after a couple of firings then it definately has too much headspace. Looking at the pictures the factory firing doesn't appear to have a crisp shoulder so the case moved some and that is why the primer is extended. The case you seated long has a crisper shoulder. That's why you seat bullets long to fireform on rimless case. If it was a belted case not as critical because the belt doesn't allow much movement. Nosler manual says to seat bullets long and use a light to medium charge of a faster powder. The shoulder is going to move or grow on an ackley improvement as that is how you increase the shoulder angle and capacity as the neck shoulder line can't move. I would load some to just get the bullet to the rifling if it will reach. You should be able to pull the bullets out some on the factory shells if you have the equipment. You can decrease the charge a couple grains if you want. I shoot a 257 Roberts, 35 Whelen and 375 H&H all Ackley Improved. Hope this helps some.

 

[450 Dakota]

Ps, if your not comfortable with it you can check with Kevin Weaver of Weaver Rifles in Peyton, CO outside of the springs there to have him take a look at it. He does a lot of wildcats and ackley's.

 

[Milehighshooter]

450 -
Thanks! I haven't shot any formed cases yet. I shot a box of the same Hornady last year, and 2 rounds of superformance, which 1 split so I stopped. I used the method you mentioned from Nosler. I have the 10 cases to work with for now before forming any more.

Kevin seems to do great work. I've seen some great rifles on several boards.

 

[450 Dakota]

No problem. Kevin is a great. He's done a coupke rifles for me. If you have any more ? Hit me up.

 

[Milehighshooter]

No problem. Kevin is a great. He's done a coupke rifles for me. If you have any more ? Hit me up.

Could always use 257 AI load suggestions!

 

[450 Dakota]

Mine is on a long action pre 64 so I can seat my bullets way out there. I'm shooting the 115 Bergers with H4350 and CCI BR2 primers.

 

[Milehighshooter]

Mine is on a long action pre 64 so I can seat my bullets way out there. I'm shooting the 115 Bergers with H4350 and CCI BR2 primers.

The one I'm working with I bought for my dad. Its a tang safety Ruger. The form load was 117gr Hornady btsp and imr4350. Shot pretty decent for picking a midrange load for forming. Have a bunch of those 117s, a lot of the discontinued hornady 120 gr hollow point interlocks, 115 Partitions and just ordered 100 gr Ttsx

 

[450 Dakota]

Great thing about ackleys is you can get rid of bullets and powder you don't want during fire forming. Ha. If I've cleaned the gun I will fireform 1-2 with the bullet I'm going to shoot for group and when I get to my cleaning interval I will fireform 5 with any bullets I want to get rid of then clean it. This routine always keeps me in brass.