Calling all gunsmiths

[Joefrazell]

 

[cohunt]

what is the actual dimension on that part of the brass? --not how much expansion, but the actual dimension

saami chamber specs show a .4740" at bolt face, and .4708" at .200" away from bolt face-- specs also show a +.002" variation so .200" up from the head can be as large as .4728"

 

[raider1v1]

what are the steps that someone would take to diagnose an oversized chamber? is it just off the fired brass?

 

[cohunt]

what are the steps that someone would take to diagnose an oversized chamber? is it just off the fired brass?

chamber cast would be the first step in my eyes

 

[Elk Hunter 338]

Ok so this has happened before with brass manufacturers and ive seen it on quite a few newer cases where they build the brass slightly under spec and short, in one case the halted production of a very popular cartridge just lately because of this ( this is also why its extremely important when spec'd wildcats are built off the exact brass you wish to use)).. so when the case is fired it has to expand forward and out which in turn shreds the brass.

what your seeing in the "bulge" is not uncommon and actually happens to a lot of factory rifles with sammi spec'd reamers where the brass flows to the weakest spot first and fills chamber up ..

what brand of brass have you used??

Your gunsmith called it good and the factory called it good I'd bet money on the fact it was a brass issue! and I would say that its to hard and not flowing like it should!!

the brass and ammo guys have so many rifles to be able to shoot in they have to make them on the smaller end of sammi to work in all rifles

 

[Joefrazell]

.4705 is what I'm getting so it's within spec. This is really strange though.

 

[Joefrazell]

I've used Barnes brass, Winchester and federal. All doing the same thing

 

[KyCarl]

Why not just check the chamber with a bore gauge? It will show if it's round
tapered or stepped. Then you know where you are...

 

[DSheetz]

What are the spiraled looking marks by your thumb ? If you are not confident and comfortable with it sell it or getting it set back one turn and rechambered by your gun smith may be something you may want to think about . If you do get the chamber checked and find it out of round , or over sized , maybe right on the edge of being of being oversized or just about too deep so you have too much forward case growth then that is probably what you will do with it any way . Just some of my scattered thoughts .

 

[arch408]

Looks like classic case head separation caused by excessive headspace to me. When the gun is fired, the case "grips" the chamber walls and after preasures builds, any space has to be filled and the case head is forced back to the bolt so the case is stretched. Unless you neck size only, the case has to stretch slightly every time you fire it. If it happens on the first firing, I would think that there is some thing wrong with the chamber. I would go to a different gunsmith to check the headspace, or buy your own headspace gauges. Sometimes, they aren't much more than a gunsmith charges to do it for you. Some thing else you could do is get some .338-06 or 35 Whelen brass and resize it in stages until it barely chambers to insure minimal headspace. Fire it and see if does the same thing. Also see if your fired brass will chamber in other rifles. If it absolutely will not go in, I would suspect a bad chamber. Also, if their fired brass chambers easily in your rifle, and yours doesn't in theirs, I would suspect a bad chamber. If the factory said it was good and won't attempt to fix it, I'd get rid of the gun or since you are a reloader, I would set the barrel back one thread and re-chamber to a 30-06 AI. That should completely clean up the old chamber and should give you a slight boost in performance.

 

[Elk Hunter 338]

I've used Barnes brass, Winchester and federal. All doing the same thing[/QUOTE


all of this is brass brand new from a bag or from factory ammo recycled??

 

[Arkansasdad]

Hey everyone, I bought a bergera b14 Hunter in 30-06 for my wife about a year ago. Ive shot it a bit and just started reloading for it about 6 months ago. I started noticing some real strange cracks right where a typical case head separation happens. Its basically like a start to one. Now this is after only 1 reload on the brass. I've tried 3 different brass manufacturer's and all do the same. So I starting really looking at the factory brass that had only been fired with a factory load and noticed a very very faint cracking in the same area. It's very hard to see but it is there and appears to be a start of a separation. So I went ahead and have the rifle to my gunsmithing just to check the headspace real quick. It was right on the money. He said to send it in and see what they say. So I did. A month later I just got the rifle back with a clean bill of health and they said they cleaned and lubed it, shot it 3 times and everything is ok. So i just got back from shooting it and it's still doing the same thing. I also noticed that it's got a pretty noticable bulge right in that area towards the bottom of the case. ( Sorry not sure what that area is called). I measured it a s it's .006" of a bulge. My question is is this excessive and why I'm getting the issue? I'm going to call bergera tomorrow and see what they say but wanted to be informed by those who know more. Thank you

I would make a chamber mold to see what is going on in there. 30-06 are not hard on brass, I have some that have been reloaded 12 times.

 

[nicholasjohn]

Looks to me like the chamber is oversized and causing the case to over-expand, bulge, and crack. If you're seeing 0.006 of expansion compared to sized brass, that's huge and the problem is the chamber.

I had this problem years ago, and a gunsmith that I trust determined that the chamber was too big around. The cartridges also did not expand the same all the way around ( the bulge was more evident on one side ) because the cartridge way laying in the bottom of the oversized chamber when it was fired. All the excess space was above the cartridge, and when it fired the case head was pushed against the bolt face, and the brass flowed in the only direction it could go. Hence, the expansion of the case walls was asymmetrical ( relative to the case head ) but still round. This can also be caused by the extractor pulling the case to one side of the oversized chamber. In either instance, the cartridge case will have a bulge that shows more on one side than the other.

The rifle I had with this problem also had a headspace problem, so the chamber was just too big in every direction. It was a 30-06 Ackley, and factory loads would often not even fire. I had the situation remedied, but the gunsmith had to set the barrel back several threads to get rid of the too-large diameter. The only thing good about the original chamber was that it was straight. A crooked chamber isn't something that could be cleaned up by simply setting it back and re-chambering - the reamer will follow the old crooked chamber.

When I first noticed the problem, I did a quick & dirty check by wrapping scotch tape around a factory-sized case. My chamber would swallow one with 2 turns of tape around it ( just ahead of the extractor groove.) When I told the guy who built the rifle about it, he told me that I was full of it, and refused to deal with it. Needless to say, I don't deal with him anymore.

 

[Joefrazell]

The Winchester brass is brand new