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 doesnít 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 donít 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 Ĺ 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 havenít resized yet as I think these might be toast. Iím 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 donít 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 boardís opinion. I will try to post a picture of the brass. If there is any other information I can provide let me know.
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.....
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.
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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.
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.