SVT 40 issue

jongun

jongun

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Well decided to take a look at the brass from my SVT 40 I was shooting the other day and to my horror realized the majority of the cases have split necks. Looks as though they are not quite snug in the chamber and when fired are stretching out causing the brass to thin and split. The ammo I was using is Sellier&Bellot SP 180gr and I measured the average length of the cases after firing and it was 2.122" and for comparison using the same ammo my Mosin gave an average of 2.107".Brass looks good from the Mosin.I'm interested in reloading for both rifles but may just reload for the Mosin and just shoot the cheap surplus in the SVT 40.

Any thoughts about this? Don't figure there's much I can do :(
 
You could try turning the gas down a touch, is it set to 1.3? Those guns have fluted chambers to assist with extraction, that may be part of the issue. You could also try some PRVI brass, who knows. I just fire MFS non-corrosive through my SVT, it's cheap and dirty, just the way I like it
 
Not sure what it was set at as I'm not 100% sure how to read the gas setting but would assume the higher the number the higher the pressure. Also would the number that's facing down towards the barrel be the set pressure? That seems logical to me as that is where the gas comes from. The necks are also quite obviously marred from what I now know is the fluting in the chamber. I've compared prvi brass to s&b brass in 7.62x39 and the prvi seems a whole lot better so may have to give that a try. Reason I want to reload is the MFS ammo is steel core or steel jacketed depending on the ammo you get and thus not allowed at my range :(
 
Okay so found out from another source how to read the gas setting and mine was set at 1.5. It is now set at 1.1 and I will go from there to see if that helps at all.May be a while before I have a chance to get some more ammo to test though :(
 
Another post reminded me of something I forgot to mention in my original post concerning the fact that the primers were left protruding after firing. This leads me to believe I've got some pressure issues as I've never seen this before in other firearms.

Please any advice is very much appreciated :)
 
Rocket Surgery said:
You could try turning the gas down a touch, is it set to 1.3? Those guns have fluted chambers to assist with extraction, that may be part of the issue. You could also try some PRVI brass, who knows. I just fire MFS non-corrosive through my SVT, it's cheap and dirty, just the way I like it
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My SVT has to be set to 1.5 to eject the MFS 203gr reliably. What setting are you running?
 
jongun said:
Another post reminded me of something I forgot to mention in my original post concerning the fact that the primers were left protruding after firing. This leads me to believe I've got some pressure issues as I've never seen this before in other firearms.

Please any advice is very much appreciated :)
Click to expand...

More likely you have headspace issues.
 
jongun said:
How would I go about addressing a head space issue?
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Protubing primers can be a sign of low pressure as well, in your Mosin, the primer set back flat after firing? I'm sure its not a headspace problem, dont forget that sometimes, on military rifle, chamber are cut generously and with goods reasons, a round must be able to chamber even when the chamber is dirty or there's dirt on ammo as well hence the reason to a large chamber. This is even more important in a semi auto rifle. A bolt action rifle is easier to chamber a dirty round because the bolt have more caming force if i can say. Large chamber doesnt mean excessive headspace. I have a Lee Enfield that left protubing primers after firing and the headspace is correct.

Joce
 
svt1940 said:
Protubing primers can be a sign of low pressure as well, in your Mosin, the primer set back flat after firing? I'm sure its not a headspace problem, dont forget that sometimes, on military rifle, chamber are cut generously and with goods reasons, a round must be able to chamber even when the chamber is dirty or there's dirt on ammo as well hence the reason to a large chamber. This is even more important in a semi auto rifle. A bolt action rifle is easier to chamber a dirty round because the bolt have more caming force if i can say. Large chamber doesnt mean excessive headspace. I have a Lee Enfield that left protubing primers after firing and the headspace is correct.

Joce
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Yes the primers are left flush(at least not protruding) after firing in my Mosin. I can see the logic in having different length chambers in semi auto and bolt action rifles of the same so called chambering.So more and more I'm thinking that there's nothing I can do to make this rifle not destroy my brass and therefore wont be expecting it not to :D

Should have asked this before but does anyone get reloadable brass from their SVT 40's? For example brass from my SKS gets pretty scuffed up from what I assume is from hitting the op rod but still looks plenty safe to reload. No marks from extraction in the SVT just the marred necks from the fluted chamber and of course the splitting.
 
jongun said:
Yes the primers are left flush(at least not protruding) after firing in my Mosin. I can see the logic in having different length chambers in semi auto and bolt action rifles of the same so called chambering.So more and more I'm thinking that there's nothing I can do to make this rifle not destroy my brass and therefore wont be expecting it not to :D

Should have asked this before but does anyone get reloadable brass from their SVT 40's? For example brass from my SKS gets pretty scuffed up from what I assume is from hitting the op rod but still looks plenty safe to reload. No marks from extraction in the SVT just the marred necks from the fluted chamber and of course the splitting.
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You can reload SVT brass but dont expect manys reloads. Mark on the neck disappear on resizing for the most part,just watch for split neck.
Joce
 
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