SVT40 / Ammo issue.

tswancoat

tswancoat

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So awhile back I got a SVT40 and today I was finally able to get it out to the range. I had thoroughly cleaned it prior to taking it out. Ammo came from CT and looks like this:



Dropped in 1 round to start and it was a FTF. Ejected the round, primer has been struck but no boom. Ok, so I load another single round and it fired, ejected and the action locked open. Perfect! Grabbed the spent case to inspect and it looked like this:





Hmmm. Pretty dirty. Looks like some gas is blowing back about 2/3 of the case length before stopping. Well, let's try this one more time. Load 2 rounds to see if action will completely cycle. Pull trigger, it goes boom but fails to eject spent casing. It looks like this:





Dirty again with debris blown to the back of the case. Didn't feel any gas blow back bu I'm guessing enough escaped to prevent the action from cycling fully however I'm no expert on the subject.

Had a couple more FTF's and decided to call it to do some investigation.

Here's a pic of an unfired primer:



The case dimensions are spot on with the exception of the neck diameter. Supposed to be 0.336" and measured 0.333" so pretty negligible or no?

So what do you guys think? Weak firing pin spring? Primer pockets too deep? Firing pin too short? Any insight would be appreciated

Tyson
 
They looks like the empties my SVT's throw maybe a bit more blowback on yours, I believe they have a fluted chamber and that's why you see a bit of blowback, keep in mind that Chinese ammo is a bit dirty. I've never had and issue with FTF's in any of my SVT's, they strike primers pretty hard, try with different ammo, could be really hard primers (I've never shot Chinese ammo in that date range). As for failing to eject, try turning up the gas setting with that ammo and see if it makes any difference. Remember, you want it to run in the lowest possible gas setting, I have one that likes 1.2, another that gives me a few stovepipes at 1.3, depending on ammo.
 
I don't like the look of fired cartridge. Try to clean the chamber with with toothbrush - maybe there's some hardened cosmo there. Inspect visually.
As for FTFs - check if firing pin moves with no obstruction. Try soviet surplus or bulgarian surplus ammo. Some ppl report FTFs with chinese.
 
The cases are normal for a SVT-40. They have a fluted chamber to help with extraction and that is what causes it (and is also why it is next to impossible to reload for a SVT-40). Mine does the same thing as yours with most surplus. These are not rifles that will run with every type of ammo and some are very picky. Personally I just use the MFS steel case now as there was only one type of surplus my rifle actually liked and would shoot everytime (and unfortunately I didn't stock up on that one kind).
 
OP, do you know what your gas setting is? That may be the reason you're not getting it to eject as well as it should. The gas setting on mine is at 1.5 right now and it ejects fine (briskly, I might add :d ).

The cases are normal for the SVT, as it does have a fluted chamber to help with extraction/ejection. You may want to try to get into the chamber with a chamber brush and clean out the cosmo that might be in the flutes themselves. If you have a long enough cleaning rod that the chamber brush will fit onto, you could use a power screwdriver or electric drill to really make that chamber brush spin. Of course, you have to put some kind of solvent (I use Hoppe's No 9) on the brush.
 
I've got some that look like that, while others eject much cleaner. Its not unusual at all. My "dirtier" svt's are the ones with better rifling. How does the bore/rifling look?
 
Hey thanks for all the quick replies fellas. I'm gonna give the chamber another once over just to be sure then tinker with the gas settings to see if I can get her to spit em out properly. It's currently at 1.3.

Still a bit unsure about the FTF problem though.

Tyson
 
I was shooting some of that code 61 stuff too and had some ftf. Hasn't happened with other ammo. That chinese 61 89 is very good though overall. My scout mosin setup shoots its best groups with it.
 
clean the chamber with AR15 chamber brush. attach it to a drill and go at it. make it as shiny as possible. Ive dealt with this problem on couple of my friends SVTs after i cleaned the chamber for them the problem was solved
 
tswancoat said:
Hey thanks for all the quick replies fellas. I'm gonna give the chamber another once over just to be sure then tinker with the gas settings to see if I can get her to spit em out properly. It's currently at 1.3.

Still a bit unsure about the FTF problem though.

Tyson
Click to expand...

Ftf probably ammo related. The chamber is fine. It is striated to reduce surface area on the case to help with ejection.
Dial if up a notch and it will probably be spot on. Adjustments may be necessary for different ammo.
 
I have not had very good luck with PRC ammo. In both my 2 SVTs and my freinds, we get the odd ftf. They run great in all the Mosins but hard primers rule them out for many SVTs.
Just last week, we took out 4 91/30s. We fired 5 rd groups at 100 yards with both Chinese and eastern block (Bulgarian) ammo. In all cases with all 4 rifles, the Chinese had groupings at lest 25% larger. The Mosins were all in excellent condition and one of them is a Finn with Tika barrel that shoots consistently 2.5' groups at 100.
So I would say that was a pretty good test.
The Chinese ammo was the stuff from Canada Ammo. Great for plinkin with a Mosin but not for anything a bit more serious.
My buddy came in third place at last years Calgary battle rifle shoot with his Mosin using Russian ammo.
 
Fluted chamber has nothing to do with the fact that extracted case body is covered in powder residue all the way down to the rim. Groove cuts contribute the the black lines on the case neck and shoulder only. There are two things that could cause this: a) hardened cosmo or pitting in the chamber and b) some amount of extremely dirty powder residue could get into the chamber _after_ the case was extracted and thus next chambered case is dirty.
There's nothing to worry in case b) but case a) is not good, it could mean that expanding case does not seal the chamber properly. Thus I would recommend to give a good cleaning to the chamber and thoroughly inspect _first_ fired case. It should be reasonably clean except for black lines caused by groove cuts.
 
Horilka said:
Fluted chamber has nothing to do with the fact that extracted case body is covered in powder residue all the way down to the rim. Groove cuts contribute the the black lines on the case neck and shoulder only. There are two things that could cause this: a) hardened cosmo or pitting in the chamber and b) some amount of extremely dirty powder residue could get into the chamber _after_ the case was extracted and thus next chambered case is dirty.
There's nothing to worry in case b) but case a) is not good, it could mean that expanding case does not seal the chamber properly. Thus I would recommend to give a good cleaning to the chamber and thoroughly inspect _first_ fired case. It should be reasonably clean except for black lines caused by groove cuts.
Click to expand...

That is what happens when I use steel cases (which aren't the best for sealing) and I had the same results when trying to use the same type of Chinese ammo the OP is using (which is believe is copper washed steel if I remember correctly).
 
tswancoat said:
Hey thanks for all the quick replies fellas. I'm gonna give the chamber another once over just to be sure then tinker with the gas settings to see if I can get her to spit em out properly. It's currently at 1.3.

Still a bit unsure about the FTF problem though.

Tyson
Click to expand...

When using surplus ammo, FTF's really aren't that common, but they do occur. IIRC most of the 54r surplus ammo available now was intended for use in machine guns, so quality control isn't a real priority. I've had a couple of FTF's from Chinese surplus ammo in both my Mosins and SVT.

It's probably a bad primer.
 
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