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Discussion Starter #1
Guys, I don’t have any pictures of the casings so I’ll be as descriptive as possible.

I got a 1941 Soviet refurb (my first SVT) that I finally took to the range. Cycles fine. Inspection of the case after the first shot showed that the case had bulged near the head, and bent the axis of the head slightly (if you set it on a level surface the case doesn’t quite point up straight. Case neck looks fine, and this was trialed on both soft point and FMJ Black Bear steel case. Not terrible bulging like the case was gonna blow, but enough to concern me. This all happened on the 1.3 setting and I’ve since dialed it down to 1.2 and given the rifle a fine tooth comb proper cleaning. I discovered no obvious issues during my inspection/cleaning.

Any input before I attempt to fire once more?

Herk
 

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I have not, I’d need to get the gauges.
From what you describe the bulging at the casehead could be down to excessive headspace, as 54r headspaces on the rim of the case if the headspace is within specs the casehead is fully supported between the end of the chamber and the bolt face but if the headspace is excessive it could leave the rear of the case unsupported and it will bulge at the casehead on firing.....at least that's my understanding of it.
 

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Discussion Starter #5
What can one do with excessive headspace if this is the case? Hang it up on the wall?
 

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Herk: Are all the important pieces "matching" (ie electropencil)? The Soviets had available different lengths of bolts to use in refurbishment to bring headspace into spec. I've never looked at the spent cases too hard from my range SVT's as I only shoot steel surplus and it goes straight to the garbage. Certainly never had any issues with eight or so of them. What you describe sounds like the banana shaped brass that comes out of Lee-Enfields- a result of oversize chambers and loose headspace. Try to post some photos of your cases.

Ruprecht
 

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Discussion Starter #7
Herk: Are all the important pieces "matching" (ie electropencil)? The Soviets had available different lengths of bolts to use in refurbishment to bring headspace into spec. I've never looked at the spent cases too hard from my range SVT's as I only shoot steel surplus and it goes straight to the garbage. Certainly never had any issues with eight or so of them. What you describe sounds like the banana shaped brass that comes out of Lee-Enfields- a result of oversize chambers and loose headspace. Try to post some photos of your cases.

Ruprecht
Everything is EP'd to match. Problem is, I don't have the cartridges anymore. I meant to keep them but somehow they've been misplaced. I only fired the two (1 SP and 1 FMJ) before common sense told me to call it quits. The only way to get a picture would be to test fire again. I wish I could find a reference picture to describe it.
 

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Discussion Starter #8
7.62x54.png

Please forgive me for the absolute trash paint work but I've tried my best to illustrate exactly where and how bad the bulging is occurring. The reference line on bottom is slightly exaggerated, but represents the axis change of the case head, slightly angled instead of perfectly 90 with the axis of the cartridge. There wasn't any discoloration or notable marking on the spent cartridge around the bulge.

I never claimed to be an artist :thumbsup:
 

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Remember this is a tipping bolt design'

If the round does not chamber completely and if the bolt does not completely 'tip into' to the full closed position, you will see this kind of weirdness around a fired case head.

You are fortunate that the rifle was sufficiently locked that it didn't cause an out of battery condition.


You might want to make a couple of dummy rounds to see if you can duplicate the not completely closed position of the bolt by merely cycling the action.

If you wish to test fire the rifle again, I strongly recommend you be sure your bolt goes completely into battery first.
 

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Discussion Starter #10
Remember this is a tipping bolt design'

If the round does not chamber completely and if the bolt does not completely 'tip into' to the full closed position, you will see this kind of weirdness around a fired case head.

You are fortunate that the rifle was sufficiently locked that it didn't cause an out of battery condition.


You might want to make a couple of dummy rounds to see if you can duplicate the not completely closed position of the bolt by merely cycling the action.

If you wish to test fire the rifle again, I strongly recommend you be sure your bolt goes completely into battery first.

Wow, that's a stroke of luck. I'll be honest I never lubricated it when I received it. I literally looked it over and went to the range which is unlike me. I was in a hurry. Lubrication of the entire bolt and carrier assembly was part of my inspection and cleaning, so hopefully the grease helped. I use the same lubriplate grease that I use on my Garand.
 

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2526750.jpg

This happens in two cases.
If the rifle bolt does not close fully. To do this, you can contact weapons repair specialists. They often have the necessary "calibers" for measurements.
This can also happen when a rifle has a very worn chamber. Then you can also contact weapons repair specialists.
There are also special tools to diagnose this problem. Although, you yourself can make an impression of the chamber from colored paraffin (wax) or a special alloy.
Measure the impression and compare them with the drawings.

P.S.
Try cartridges with a brass case and a copper-plated case.
 

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You gotta do something very special to force SVT to fire with bolt not fully closed. Unlike M1 Garand that will fire (and potentially could fire with bolt not fully closed) when safety mechanism is broken , SVT will not. So with functioning safety mechanism (Part 52 "Disconnector Operating Sear" according to Numrich, part #3 in original manual "automatic release" below) it won't fire with bolt not fully closed, with broken mechanism it won't fire at all. More safe for user, but maybe not the wisest choice for a battle rifle.
Of couse any system can be damaged and tricked into some weird functioning, however it would take some efforts. Do the chamber cast first. Also remove the trigger unit, see if disconnector is fine so you can sleep well, dry cycle rifle and see it does not relase trigger with bolt not fully closed. It's a simple and effective system, easy to learn and understand.

 

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Herk1944: As Horilka says, it's a well designed mechanism. With your springs removed and dustcover off (and gun unloaded!) slide the carrier and bolt back and forth. You'll feel the slight resistance just before the bolt goes into battery which is the disconnector pushing down on part #3 in the diagram (my old NRA book calls it the "disconnector operated sear"). The bolt is very close to being closed before this occurs so if all is functioning the cartridge can't be fired with much of the base exposed. With the rifle stripped, identify the disconnector and verify that it moves freely. Regarding other possible problems, do you have access to a borescope you could use to have a quick look at the chamber?

Ruprecht
 

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Don't forget to check for grunge or other junk that keeps the bolt from closing all the way. I've had that happen, especially on old military arms.
 

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Discussion Starter #15
I'll take a gander at the chamber again but everything looked clean. I did use a borescope to check the chamber. I wonder if the bolt just needed grease? It's clean and greased now. I'll get a headspace kit and use the techniques you guys have suggested for functional checks.
 
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