Only one picture shows any neck, and it's only partial on two cases. How are you able to make an assessment that they are, "ballooned" as you put it?
Brass looks terrible for once fired.
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Case separation on first firing
- Thread starter propliner
- Start date
Only one picture shows any neck, and it's only partial on two cases. How are you able to make an assessment that they are, "ballooned" as you put it?
Brass looks terrible for once fired.
The Weatherby design incorporates radiused shoulders.
The shoulder is irrelevant for headspacing a belted magnum cartridge. The belt and corresponding counterbore in the chamber mouth is where headspace is controlled. A chamber could be badly oversized or cartridge undersized and headspace could be perfect.
Factory cartridges separating on first firing...
There is either a problem with the ammunition (try a different brand or even a different lot).
Or, there is a problem with the rifle.
Stop using the rifle until there is resolution.
- Location
- Van. Is. B.C.
To me this looks like a head-space problem. Headspace for a rimmed cartridge has been covered so not going there but there is a trick the rimmed cartridge guys (.303 Brit) use. Fire the shell with a rubber “o” ring ahead of the rim to prevent the case being driven forward on firing. If you could find some you could try this. Failing that put a layer of scotch tape on the shell head and try the fit in the rifle. If the bolt drops freely add another layer until it doesn’t. My tape is about .002” thick for this trick but measure your own to find out how much headspace you have in your rifle roughly. Finally beg, borrow or buy a set of headspace gauges to be sure.
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Too deep a ream would be my guess as well.
The only part of the case that does not seem to show movement, is right in front of the belt, which is where the headspace gage will measure. A Chamber cast to check the other directions may be a good plan.
So, it's going to need more than just a gage dropped in to it, given the gage is liable to only show you the belt is correct. A cast will tell you if the reamer is cacked.
Not gonna discount a bad batch of brass either.
Yes. It would have to be wildly too long though. Although, "wildly" in gunsmithing terms is like 0.010" or so.
You guys were right, the chamber had an awful rough finish to it. I spent some time polishing to a nice shine and finished with a slight cross-hatch and will try some different ammo next.
I'd love to send the barrel back to the manufacturer but it's not such an easy proposition. I'll see if this works first.
I'd love to send the barrel back to the manufacturer but it's not such an easy proposition. I'll see if this works first.
6.5 shooter
CGN Regular
- Location
- Medicine Hat
It looks like it is trying to turn your brass into AI brass. That weird line/circle about 1/2 way up the shoulder neck junction is concerning. If you have a set of overall length gauges (Hornady) you can measure from the base (without primers) to the shoulder neck junction and see how much the case has grown from firing compared to a factory case. I agree with most here I think it is a over length chamber. You can for a fix, anneal some brass and let it flow on firing to take up the extra space and just run with the super long chambering. However if you don't understand the process it can be a bit intimidating. There are safer way's to do it but to involved for this thread. Your best bet is to get a casting of the chamber and have a Smith or a local barrel maker with good measuring equipment to check out the casting and chamber dimantions.
How can it be to deep of a ream if the headspace is OK?
The only way it could be to deep, which is doesn't appear to be from the last pics, is if the reamer was purposely ground oversize or to special order. If it's a homemade reamer, it could just have been ground to final dimensions improperly.
I'm with the bad batch of brass on this one.
Here is the shoulder for those who want to see it.
And the measurements of new vs. fired for anyone who is an expert:
Base above belt: .509" .512"
Shoulder: .489" .494"
Neck: .2895" .299"
Those look fine to me and your measurements prove it.
Jonnyofalltrades
Regular
- Location
- North-central Saskatchewan
The measurements are certainly fine, diameter wise. The case being belted really makes it more complicated than it should be, as he can't just measure to the shoulder of fired vs unfired and see if his headspace is off.
To me those cases look like excessive headspace is the problem.
PM me if you want to borrow headspace gauges.
- Location
- Western Manitoba
What are you seeing in the pictures that suggest the headspace - from bolt face to forward edge of the belt - is "off"? There are a number of rifles chambered to various belted cases here - I would like to know what to look for. All that my belted case headspace gauges will measure is the space between the bolt face and the forward edge of the belt - so you must see something that I am not seeing, for such a gauge to show the issue.
You guys were right, the chamber had an awful rough finish to it. I spent some time polishing to a nice shine and finished with a slight cross-hatch and will try some different ammo next.
I'd love to send the barrel back to the manufacturer but it's not such an easy proposition. I'll see if this works first.
I wouldn't have polished anything personally. Kinda screws up the return for refund option as you are enlarging the chamber even more. Your gun though.
Why not?
The amount of people who don't seem to understand what headspace actually is, yet are still offering, "advice" in here is staggering.
The way I see it is a headspace gauge won't detect a problem but a go/no-go might.
Also, if the barrel was ruined due to improper reaming it was junk to begin with and still warrants a refund. Unfortunately it was virtually new yet second-hand so returning it may be impossible, and shipping the barrels back and forth even more so.
I will head to the range with two other different boxes of ammo today (if the weather holds out) and will report back.
Also, if the barrel was ruined due to improper reaming it was junk to begin with and still warrants a refund. Unfortunately it was virtually new yet second-hand so returning it may be impossible, and shipping the barrels back and forth even more so.
I will head to the range with two other different boxes of ammo today (if the weather holds out) and will report back.
I had to look it up but the belt is part of the reamer. Thus the chamber shoulder is always in the same relative position to the belt front face.
I suppose it is possible the reamer was incorrectly ground ... sh!t happens sometimes.
However it is most likely the chamber was simply cut too deep, which a headspace gauge would show. Keeping in mind the SAAMI headspace range is only 0.004" it is super easy togo way too far.
The headspace could easily by 3-4x too long, which would cause the case head separation, without any obvious damage to the primer, which is nearly 0.130" tall.
I suppose it is possible the reamer was incorrectly ground ... sh!t happens sometimes.
However it is most likely the chamber was simply cut too deep, which a headspace gauge would show. Keeping in mind the SAAMI headspace range is only 0.004" it is super easy togo way too far.
The headspace could easily by 3-4x too long, which would cause the case head separation, without any obvious damage to the primer, which is nearly 0.130" tall.
Headspace gauges are usually GO, NO GO and FIELD.
A rifle should accept the GO, may not accept the NO GO, and should not accept the FIELD.
In a belted magnum, the gauges only address the gap between the bolt face and the end of the rim counterbore in the barrel.
If there is excess headspace - a situation where the rifle would accept a FIELD gauge and could be even looser than that, the firing pin drives the case forward until it is stopped. As pressure builds, the case expands and grips the chamber walls. Because there is excess headspace, the face of the cartridge head is not in contact with the bolt face. Pressure forces the case head back, stretching the case. Stretched too much, it separates. Frequently, if there is excess headspace, the primer backs out and is then reseated when the case comes back to the bolt. Badly flattened primers can result. Your primers do not show excessive flattening.
A rifle can also gauge perfectly and there could still be excess headspace if the belt on the cartridges are short. Belts can be measured, to see if they are within specs.
Headspace gauges tell nothing about how the body of the chamber is reamed. If headspace is correct but the chamber body is too deep or to large in diameter, the case is positioned by the belt, and the case will fireform to fit the chamber. For example, if a .300WinMag cartridge is fired in a .300Weatherby chamber, the headspace should be correct but the case will fireform to fit the longer Weatherby chamber.
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If that were the issue, the primers would have backed out or been totally flattened. That's not what the pics show.
