











Unfortunately, I did not notice the cracking while I was firing. It is only by chance that I saved some of the casings and noticed the cracking later, so I have no idea if they were among the first or last rounds. I only shot a few, as I was firing the rifle for the first time, so I may have missed a few casings, but not many.desertgunner wrote:Spacecase,
the first picture: Are the shells in sequence as shot, if so, was the first to the right the first one?
If that is correct, then you have the damage building up shot by shot to the left.
IMHO this would point to heat-up and a chamber problem: Too wide when too hot....
How many rounds did you fire overall..?
Were the cracked ones in the last batch?
I would tend to agree with you, but since I did not shoot many (maybe 20 rounds), and 4 cracked, that seems like a high percentage. I'm going to have the rifle checked out either way; better safe than sorry.andrewd41 wrote:If your rifle only split a few??? I would not blame the rifle. I have put close to 400 rounds of Russian milsurp from 1976 within a month's time, and only split 3 rounds. I like you, I saved all the empty cases after each session just to see the results. 3 out of 400 lead me to believe the ammo is the suspect.
I'll add one thing here you left out. Throat errosion might be caused by escaping gases in most cases but remember these rifles were used with corrosive ammo and the throat would be a place that could be neglected to a point by someone only running a cleaning rod down the bore and not getting all the corrosive salts out of the chamber/throat. Remember also I have some 1985 Russian Lugansk that only splits cases like this in one rifle I have. A 1952 Polish M44 with a very pitted bore. It's hard to see the throat so I really don't know if it's erroded. The same ammo doesn't split like that in any other rifle though. Actually the next time Fred_G and I shot I'm doing a few ammo tests with that rifle and ammo and a bunch of other rifles and ammo. I'm going to see if any other ammo splits in that rifle. I'm also going to test some of the recent 1946 I got splits in any rifles because some have said they've been seeing this. I'll be trying out some of the 182gr heavy ball also. I'll let you guys know how it goes.Hombre wrote:I would not think it is due to throat erosion because as I said, to me the throat means the non-rifled area immediately forward of where the cartridge case sits in the chamber. The area of the chamber covered by the cartridge case is protected pretty much from erosion, by the case. (Erosion is caused by hot gases rushing over a surface.)Spacecase wrote:
Based on this, would you favor the conclusion that these cracks were most likely caused by throat erosion, or other factors affecting casing support?
It could be caused by an oversized chamber but I think your split is due to a bad case.

By definition erosion is the carrying away of material from a suface by a substance moving over it. In firearms the substance moving over the surface is hot gases. So if someone wanted to include the effect of corrosion they should say throat erosion/corrosion. I "left out" corrosion because I was asked about erosion.WeldonHunter wrote: …… I'll add one thing here you left out. Throat errosion might be caused by escaping gases in most casesbut remember these rifles were used with corrosive ammo and the throat would be a place that could be neglected to a point by someone only running a cleaning rod down the bore and not getting all the corrosive salts out of the chamber/throat. …….
My point is a void next to the case might afford a place for the case to expand to and split in the process. It's mainly just a suggestion because I'm not qualified to state it as an absolute.Hombre wrote:By definition erosion is the carrying away of material from a suface by a substance moving over it. In firearms the substance moving over the surface is hot gases. So if someone wanted to include the effect of corrosion they should say throat erosion/corrosion. I "left out" corrosion because I was asked about erosion.WeldonHunter wrote: …… I'll add one thing here you left out. Throat errosion might be caused by escaping gases in most casesbut remember these rifles were used with corrosive ammo and the throat would be a place that could be neglected to a point by someone only running a cleaning rod down the bore and not getting all the corrosive salts out of the chamber/throat. …….
However I agree that there are other things that can remove material in the throat (including cleaning with a wire brush) but whatever causes the loss of metal the throat does not support the case and changes to its diameter would not cause any splits.
I agree fully with that and if that is present I would imagine his GS could see it during his inspection. I think several of will be interested in what the GS findings are.WeldonHunter wrote:
.... My point is a void next to the case might afford a place for the case to expand to and split in the process. It's mainly just a suggestion because I'm not qualified to state it as an absolute.
Not sure what you mean by the "more forgiving "FIELD" gauge" But to me it would mean that the field gauge allows more headspace than the no go does.Spacecase wrote:The headspace gauges arrived, and my rifle passed both tests.
With the "NO-GO" gauge, the bolt did not close, and it also did not close with the more forgiving "FIELD" gauge, so that probably allows us to discard the potential headspace problem being the cause of the split cases.
Next step; GS.

I have a very good and honest GS; I'm sure you can find one like that as well.jeremyb wrote:I hope your experience with the Gun smith is better than mine.
