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  #11  
Old 10-25-2018, 05:31 PM
Bill K Bill K is offline
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Default 223AI case forming irregularities

Quote:
Originally Posted by varmintshooter View Post
When a 223AI chamber is cut a standard 223 will fit in it but it should be tight not sloppy. That is why they take about .006" off the back of the barrel when the chamber is cut. I have been wrong before but I don't think I am wrong on this.
A standard 223 R case will fit, no question about that, but since you are re-chambering to the AI version, the case taper and shoulder are slightly larger, therefore their is more diameter in the shoulder and upper case area, so it has to be blown out to fit the new 30 or 40 degree shoulder on the AI case used.
That is why you have to seat the bullet out to just touch the lands and hold the case back onto the bolt face for fireforming, or you will get that headspace ring on the case, as it is stretching on the entire case, rather than just blowing out the shoulder area. You can form a false shoulder, as mentioned, or just seat a bullet out enough to engauge the lands and end the issue of the headspace ring and the case being ruined and separation to follow at the point of the ring marking. Really a simple solution and end the problem. Bill K
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  #12  
Old 10-25-2018, 05:47 PM
varmintshooter varmintshooter is offline
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It is only the neck shoulder junction that matters, body dia and angle of shoulder have no bearing. You don't have to believe me just go over to Accurate shooter and look at the 223 page there is a case dia. of both a 223 and a 223AI case. Check the length of both, case head to neck/shoulder junction.
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  #13  
Old 10-25-2018, 06:02 PM
varmintshooter varmintshooter is offline
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Daryl did a good job of explaining what is happening here. The barrel wasn't set back properly when chamber was cut.
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  #14  
Old 10-25-2018, 06:36 PM
Bill K Bill K is offline
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Default 223AI case forming irregularities

I peruse Accurate shooter and others, plus having worked with Ackley chambers in both large and small caliber for over 50 years.
Also with the 20-223AI I have and this style has always worked for me, and have had no issues. So I believe I will continue to do and use it, which is also by the way P.O. said to do it, with his cartridges.
You, of course, are free to do as you wish also to get your cases to fireform and fit the chambers. Nuff said on issue. Bill K
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  #15  
Old 10-25-2018, 07:53 PM
Bayou City Boy Bayou City Boy is offline
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As has been stated, this is indeed a situation involving case head separation due to an AI chamber that has too much head space, regardless of how it got that way. One method the some "gunsmiths" even use today to sell you a cheap conversion is to run an AI reamer into an existing chamber to "hog it out". This never works as it should per old P. O.'s concept due to the fact that the resulting AI chamber will ALWAYS have too much head space

If a smith ever told me that he could cut me an AI chamber in such a manner, all he would soon see is my backside as I"m going out the door of his shop. He is a quack............... And a "smith" who can't cut an entirely new chamber with any reamer is a quack also, or at least he's having a really bad day at the lathe.

I suppose that having an AI chamber with excessive head space is all fine and good, including jamming bullets into the lands to compensate for the too long chamber, for some folks. However, that is a true solution only if when you die that you have the rifle buried with you. If it gets sold, the buyer now has a rifle with an AI chamber that has excessive head space, and you better hope that the buyer understands head space and what he has to do to "fix" the problem he has bought/inherited.

If you re-chamber an existing barrel to the AI version of the same cartridge, the ONLY PROPER AND SAFE way to do it is to set the barrel back at least one thread so that the chamber when properly cut will have a head space dimension that is roughly 0.004" shorter than the factory chamber. This will ensure a light crush fit on normal factory brass when placed in the AI chamber the first time. If the chamber is good, there is no need to jam bullets or do anything else to "fix" a bad AI chamber.

Where was this driven home to me long ago? It happened one afternoon that I spent with P. O himself in the Salt Lake City area years ago. He was a crusty old dude, but he knew what worked and what didn't work with his AI creation concept. He probably belches loudly in his casket every time someone on the internet suggest that jamming bullets is a requirement or a "fix" for an AI rifle to fire form brass the first time when the only real solution is to get the chamber re-cut by a true gunsmith who knows what he's doing.

Doing anything else is just a fantasy that in some situations might get someone hurt............My answer is long. varmintshooter nailed the problem and the solution with his one sentence post two posts above this and in each of his posts prior to that.

-BCB
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Last edited by Bayou City Boy; 10-25-2018 at 08:03 PM.
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  #16  
Old 10-25-2018, 10:10 PM
JSH JSH is offline
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^^^^^^^^^^^^^^^^

If more people would read and understand a TRUE AI chamber job, we would not need these type of discussions to "fix" the fix. BCB is spot on to my thoughts as well.
I had some really long discussions with guys and TC barrels. The only way you can get a TRUE AI chamber is to start with a shorter original chamber to begin with.

AI, Ackley Improved gets thrown around a lot and has for the most part become a generic term.
When a lot of these should just be considered an "I" as in improved...........if there really is an improvement.
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  #17  
Old 10-26-2018, 12:31 AM
hemiallen hemiallen is offline
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Not tagging on to anything anyone else may have said, ie I haven't read other replies:

I would take a round of this ammo and start making circles of slightly smaller diameter than the cartridge case head, of either masking or scotch tape, and start stacking them up until you get to the point the bolt starts to have resistance on trying to close it.

This thickness of discs will show you how bad, ie too long, your headspace is , FOR THIS AMMO.

And I have had this issue on a 7tcu contender, I necked up my brass with a tapered expander plug I made to reduce bumpomng more than needed, and sized it down to create a shoulder so that the brass , not a bullet, holds the head against the boltface. I have tried seating bullets into the lands, and sometimes the firing pin forces the case forward before it has a chance to expand, thus making brass that still is shy of true base to shoulder length. Confirmed with a micrometer and the ability to still add tape to the base of said not correctly formed -fired brass.

Just my experiences

Good luck

Allen
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  #18  
Old 10-26-2018, 02:12 AM
Oso Polaris Oso Polaris is offline
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Default Additional Details / Follow-up

Thank you for the feedback. Some additional details on this rifle.

It is a Rem 700 action that has been blue printed and a new Bartlein barrel blank chambered in 223 AI. The work was done by a competent local gunsmith (+30 years), whom I trust and have used on a number of projects.

I was shooting some older Blackhills ammunition and Winchester soft points. The frequency of occurrence was maybe 5% of these rounds that I shot, which is an acceptable failure rate. These cases will be destroyed...I am not running risk of case separation.

I will make some reloads and see how it does with them.
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  #19  
Old 10-26-2018, 03:11 AM
DittoHead DittoHead is offline
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Take the rifle and the stretched brass back to the gunsmith. He should set back the barrel a bit so factory ammo will form properly.
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  #20  
Old 10-27-2018, 11:42 PM
Oso Polaris Oso Polaris is offline
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Quote:
Originally Posted by DittoHead View Post
Take the rifle and the stretched brass back to the gunsmith. He should set back the barrel a bit so factory ammo will form properly.
This may be what I ultimately have to do. I plan to run some hand loads using Lapua brass as well as some new Federal ammo through the rifle and see if the issue continues. it is possible that issue was ammo specific.
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