New problem, need expertise!

Discussion in 'Gunsmithing' started by Crane, Nov 1, 2009.

  1. Crane

    Crane Well-Known Member

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    I already ran this by Kevin Cramm at Montour County Rifles who chambered and fitted the barrel along with straightening the action and he suggested I lay it on you guys as he doesn’t have much experience with 25-06AI. The action is a Weatherby/Howa long action and a new .257 Rock barrel.

    I fire formed my brass with factory Winchester 120 grain loads. I noticed what appeared to be a slight bulge on every case just above the head. I used Winchester because I don’t have a very high opinion of Remington brass. I prepped the brass and loaded eight different loads differing by 0.2 grains for a total of 16 as described in a previous thread. 110 gr. Accubond 10 thousands off the lands with a starting load of 62.6 to 63.8 grains of H-1000.

    I found a good load of 63.6 grains as a base for further testing with no apparent signs of pressure . I showed them to a friend to see what he thought. He immediately noticed the bulging and after examining all the cases we discovered one that was cracked right at the bulge about ½ way around. This was not the highest load tested, I know because I had them labeled with the load. It was the 63.4 grain load. That case had to be very near total head separation. I cleaned and annealed the cases I shot minus the cracked one. I haven’t resized yet as I think these might be toast. I’m going to try to get a couple of different factory loads with other than Winchester brass to see if the effect is the same.

    From reading on another thread it sounds as though there might be a problem with the chamber itself or the bolt being off center of the chamber since the initial bulging happened with the factory loads. I don’t know the procedure used for chambering the barrel or whether go-no go gauges were used. Maybe Kevin will add that information.

    Again, I ran this by Kevin first as not to appear to be hanging him out on a forum before discussing this with him and he suggested I get the collective board’s opinion. I will try to post a picture of the brass. If there is any other information I can provide let me know.
     
  2. Gnarly

    Gnarly Active Member

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    Crane,

    First off,I'm not qualified to answer!

    However,the only time in 44 years of hunting & handloading that I've seen a rifle do this consistently,the 'chamber is slightly too long' was the concensus.

    I'd be helpless to explain how this conclusion was reached,but I do recall that when the barrel was set back by the gunsmith,the problem went away & never re-surfaced.Neighbor still uses that rifle.

    Back to the go/no-go process....

    Hope this helps.

    ----Gnarly
     

  3. Crane

    Crane Well-Known Member

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    I've never fire formed loads to Ackley configuration before but I was expecting, based on what I have read, a slight "crush" fit to the standard case loads when chambering. I never felt anything, the bolt closed normally. This sort of goes in line with your slightly too long chamber theory. I dunno.....
     
  4. Crane

    Crane Well-Known Member

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    I would like to hear from some of the smiths that do this for a living.

    CHAD...KIRBY...J E CUSTOM... NATHAN, share your thoughts if you don't mind.
     
  5. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    The barrel was chambered the same as any other barrel I would do and I have a hard time believing I chambered it too long. I use PTG reamers and gauges exclusively also. I went out to the shop tonight and pulled both the reamer and go gauge I used on the 25-06 AI barrel. They are both engraved from PTG 25-06 AI. I use just the go gauge and for a no go gauge I put one strip of scotch tape on the base end which adds .002" to the length of the gauge turning it into a no go gauge. When the headspace measurement I took from the action face to bolt face is very close I turn to the gauge. If I can close the bolt with the go gauge and not when a piece of tape is applied I'm done. I've used this method hundreds of times and I've never had a problem. My only other thought is that possibly the go gauge is either ground to the wrong measurement or it could be mis labeled. I'm going to send Derek the go gauge to try and make sure the chamber isn't too long to the gauge I used. It's easier to eliminate that variable first.
     
  6. Coyboy

    Coyboy Well-Known Member

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    I have noticed with certain lots of Winchester brass that the case heads/ web areas are undersized in dia.

    This causes the bulge in the case body ahead of the web. as the webs are to thick to stretch to chamber dimension.

    If you size the brass FL and the bulge is still noticable than most likly it is an undersized web, That or measure your webs and compare them with a cartrige diagram, you can also measure the bulged area and comapare that to what the cartrige diagram shows.
     
  7. hammertyme

    hammertyme Well-Known Member

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    Along with what Jim said, I purchased a lot of Winchester brass that after FL sizing I could not get one case to enter a chamber. Unfired, every one of those cases were too large in the pressure cup area so I dropped in another brand of brass without issue.

    I have also seen new and old reamers cut a chambered oversized (diameter), causing the same problem. Though this is a new barrel so probably does not apply. Re-chambering factory chambers to the AI round I have seen that bulge you refer to because many factory chambers are not concentric to the bore. A quality gunsmith comes behind and indicates to the bore and chambers leaving a non-concentric( not round) chamber.

    When fired that particuler bulge is always in the same spot on one side of the case.

    Neal
     
  8. J E Custom

    J E Custom Well-Known Member

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    +1
    This would be my 1st choice for the perceived problem also.

    Most factory ammo is sized smaller than SAAMI specs so it will chamber in any chamber
    clean or dirty. If you have access to a micrometer measure the fired case at the bulge
    and then compare it to the SAAMI chamber specs and this will tell you if it is a chamber
    problem or a brass problem.

    I would not think it was a head space problem because Kevin is a good smith and could
    not miss the head space enough to create this problem unless the wrong gauge was used
    by mistake (I once used a field gauge buy mistake but caught it before the chamber was
    finished).

    The only other thing I can think of is, If the tail stock is knocked off center by a few thousandths
    it will make the rear of the chamber a little larger than the reamer. (Been there to)

    Most factory ammo will have a slight amount of expanding at the base and some is normal
    If you could post a picture we could probable tell if it was excessive.

    Either way I know that Kevin will take care of you.

    J E CUSTOM
     
  9. NesikaChad

    NesikaChad Well-Known Member

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    Ok, you've got an Ackley case which means you start out with a factory case and blow it up to the new chamber like a balloon inside a piece of PVC pipe.

    The key to getting the Ackley stuff right is in the initial fire forming. Here's a grossly over exaggerated example to illustrate the point.

    Lets take the 22-250AI as the example. I build the gun set up for 80 grain bullets for long winded dog shots. I run down to the wally world and buy a box or two of 40 grain verminator bullets and off I go to the range to fireform my cases.

    That is my first mistake and here's why:

    In order for the AI to work right during fire forming I have to make sure the ass end of the case is shoved up tight against the bolt face. The only way to do this when you have a cartridge that starts out physically smaller than the chamber is to seat the bullet long so that it has a good healthy bite into the lands. You effectively headspace the initial fire forming off the throat and the bolt face instead of the shoulder because the cartridge is no where's near the shoulder yet.

    What happens if you fail to do this is the striker pushes the whole thing forward until something stops forward motion, be it either the shoulder of the chamber or the throat of the barrel. Pressure acts on everything it touches at a right angle. This means it's pushing forward, outward, and REARWARD because there's nothing to stop it until the case contacts something that will resist being pushed around. (the chamber, bolt face) The rearward movement is what should concern you. Your case webs are being stretched out like the pivot girl after the homecoming game. Worse actually.

    Start over with new brass, load conservatively, seat your bullets long so that it takes a bit of "umphff" to get the bolt closed, and then go shoot em. If you still have problems then I speculate you have a chamber problem, the reamer either went cockeyed or the headspace is somewhere in the bad place of tolerance.

    Last, I personally avoid using dies from any company other than Redding or Wilson as the others seem to run on the tight side and this will only raise even more hell when fiddling with fireformed wildcats as the brass has to move even further.

    Hope this helps.

    Cheers,

    Chad
     
    Last edited: Nov 2, 2009
  10. Crane

    Crane Well-Known Member

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    A friend is supposed to bring some assorted factory rounds to try other than Winchester.

    JE Custom - I'm not worried about Kevin in the least. In my limited experience in dealing with him I know he's a stand up guy. He communicated with me every step of the way, confirming specs and delivered exactly when he said he would. If this turns out to be bad brass then we've figured it out if not, well things happen sometimes and I'm sure everything will be made correct.

    Nesika Chad - I understand what you are saying but wasn't it one of Ackley's intentions that factory loads be used or was that only supposed to be in a pinch? I used the 120 grain loading, the heaviest I think are available and used 110 grain Accubonds to work up loads with. The dies are Redding.

    Not a great picture:

    [​IMG]
     
    Last edited: Nov 2, 2009
  11. Crane

    Crane Well-Known Member

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    A better one. Notice the dark area between the two bright lines.

    [​IMG]
     
    Last edited: Nov 2, 2009
  12. Crane

    Crane Well-Known Member

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    Here's a picture of the rifle. The med Z-Rings are a little high with the 20 min rail and the 40mm objective on the Elite 6500. It has the STOCKYS STOCKS Coffee thumbhole on it. All metal except Stainless barrel is Duracoated Wilderness Brown. Sorry for the picture quality.

    [​IMG]
     
    Last edited: Nov 2, 2009
  13. bonefisher

    bonefisher Member

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    I have the same problem or issue with a 280AI. Posted questions about it last night on another forum. There is some other guy with a 223AI who posted the same issue 2 days ago as well. Answers are all over the map. Range from "normal" to you are about to have case / head separation. Bulge area on my fired rounds averages .013 larger than unfired case.
     
  14. jmason

    jmason Well-Known Member

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    Crane- I think you may have misunderstood Chad's post. You have proven that factory ammo will shoot out of the gun if needed to in a pinch. What Chad is saying is that the case needs to be positioned properly in the chamber in order to stretch properly. Your stretching the cases at the head instead of the neck shoulder area. He is saying that you need to make sure that the case is held against the bolt face when fire forming by using the COAL to hold it there. Please don't take what I'm saying wrong as I'm trying to be helpful. Maybe try loading up and forming a round or 2 as Chad describes and see what happens rather than using factory ammo for fire forming.:)