POI shift on the SVT

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Rayleigh_Scattering

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This weekend I failed miserably in my attempts to hit things with my SVT-40.

The lion's share of the problem is likely my own lack of skill and experience. I need practice with trigger usage, and I need to improve my tooling for ammunition manufacture. I also need to find or figure out techniques for "how to aim while breathing hard and kneeling on rough ground", which will require some thought (including path planning and signature management).

But I do know that the POI on this thing shifts as it heats up. I saw that while sighting it in, in a vague sort of way, and am pretty sure it manifested on the weekend.

Is there anyone out there who can relate their experiences with their SVT, and how the POI shifts? Also, what did you do to manage this effect, and to what extent did you succeed?
 
What distances were you shooting from? And what size targets? Only tried kneeling or tried a rest to confirm?
And why don't you try using store bought ammo just to test things out.
 
norlandgeese said:
What distances were you shooting from? And what size targets? Only tried kneeling or tried a rest to confirm?
And why don't you try using store bought ammo just to test things out.
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In the field c100m, basketball sized target, kneeling with no rest.

Sighted it 2 days earlier for 2" high at 25m (indoor), kneeling with rest.

Confirmed on-target at 50m prone with improvised rest that morning.

>store bought ammo

May have to. That would remove one of the uncertainties.
 
If your 50m prone confirmation was grouping good, then as next steps I would recommend trying store bought ammo+ 100m Prone/Rest, as an additional measure if you are afraid of not being on paper at 100m add a large cardboard backing behind your target.


Rayleigh_Scattering said:
In the field c100m, basketball sized target, kneeling with no rest.

Sighted it 2 days earlier for 2" high at 25m (indoor), kneeling with rest.

Confirmed on-target at 50m prone with improvised rest that morning.

>store bought ammo

May have to. That would remove one of the uncertainties.
Click to expand...
 
Rayleigh S.: I have done a fair bit of shooting with half a dozen SVT's and shifting POI was not an issue with any of them (many other issues, however). I've noted horrible (long) trigger pulls, very loose fit of barreled action in stock, poor general "bedding" in refurbs, pretty marginal bores in some, rear sight slider shifting on firing (caused vertical stringing, obviously), etc, etc. I have one that simply won't shoot well but have a couple that are excellent and will due 1.5- 2.0 inch 5 shot groups at 100 yards.

I would recommend doing some testing with the gun in a lead-sled type arrangement on a bench to try to remove operator error as much as possible. The trigger pull is so different on these that I have a hard time going from SVT to something like a Lee Enfield on the same range trip.

If, after testing, you do have bad vertical stringing you could check that there is some free-play in the lower metal guard, when cold. If this is tight then heating of the barrel might change POI. Think Garand. You may also need to shim the receiver in the stock or even work on the bedding at the forend tip to, possibly, fix it.

milsurpo
 
Milsurpo, I read some where recently a method for improving accuracy on these rifles. He made sure the barrel channel was clear, spot sanding contact points between barrel and stock, then shimming under the barrel band area to have a solid contact point. Have you ever tried anything like this?
 
1) Check actions screws are tight.
2) Keep your head on the same spot (cheek weld).
3) Keep your thumb on the 1st finger side of the stock, don't wrap it over the wrist.
4) Same pressure against the shoulder for each shot.
5) Don't clutch you fingers on the front hand, just let the rifle sit on the palm between the thumb and first finger. otherwise it will shake.
6) Learn to use a sling as a shooting aid.
7 to infinity) Practice dry firing and calling your shots.
You should always be able to tell where your shot was aimed at.
 
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BTW Rayleigh_Scattering, what MOA / inches grouping and vertical stringing were you actually getting at a 100m?
I re-read the posts, just want to make sure we are not chasing unrealistic capabilities from a off-the-shelf old SVT.
 
I'd stay away from aftermarket ammo for the SVT40, the higher bullet weights tend to run the action really hard. Shooting 180gr, mine eventually broke operating on 1.1 gas setting. Keep in mind though I was operating stainless steel piston and cup set, with slide with a lot less friction than the rusty pitted stock ones .
 
JDForBrkFst said:
Milsurpo, I read some where recently a method for improving accuracy on these rifles. He made sure the barrel channel was clear, spot sanding contact points between barrel and stock, then shimming under the barrel band area to have a solid contact point. Have you ever tried anything like this?
Click to expand...

Yes, with a few rifles. I found full floating barrel to work best but also some success with increased up-pressure at forend tip (either by shimming there or by shimming at rear of receiver flat which rotates everything around the stock pin). There should be a few old threads here and on gunboards showing what people have tried. On a historical note I would say that bedding with pressure at forend tip (actually through the metal ring on the upper guard) was what the Soviets started with. In the best book on the subject (by Chumak, and in Russian) the author presents info that this form of bedding may have been the cause of accuracy issues. He also claims that "2 point bedding" (which I believe to mean full float) was being tested at one point. My most original SVT 40's ('43 Bulgarian light refurbs) have definite full float created by inletting at rear of upper flat on stock.

milsurpo
 
norlandgeese said:
BTW Rayleigh_Scattering, what MOA / inches grouping and vertical stringing were you actually getting at a 100m?
I re-read the posts, just want to make sure we are not chasing unrealistic capabilities from a off-the-shelf old SVT.
Click to expand...

I can only estimate the actual angles and distances.

I remember clearly dirt puffing up on the hillside left, right and above the deer as it stood there staring at me from something under 100m.

After running out of bullets I switched to profanity and jumping up and down making rude gestures (which proved about equally effective). At that point he spotted me and trotted off over the hill in a not-particularly-excited fashion.

I'm not proud of my marksmanship, although my signature management appeared to be working, and I'm pleased to say that my check-for-backstop-before-finger-touches-the-trigger interlock was nicely engrained.

I'll either have to get significantly better at this, or I'll have to pull my engagement envelope in much closer and put more skill points to stalking. Spray-and-pray is not the way to do this.

Those are excellent points Diopter, as I see I was doing most of those things wrong. Excitement and poor technique may be the problem, but those are both things I can work on.

>higher bullet weights

123gr soft point. Mid-range load of 4895, with no pressure signs on the primer of the one casing I recovered and flawless cycling at a setting of 1.3. A bit light, but it's all I could get in Calgary when I needed it.
 
Rayleigh S.: What exactly is "signature management"? Not familiar with that one! A properly functioning SVT 40 should be able to give you perfectly adequate precision for hunting. I should have asked before if you have managed to get it perfectly zeroed? I have one that was shooting 2 ft low and to the left as purchased (right fresh from refurb). A session with a good bench where you can really establish some baselines would probably be very helpful at this point. I'm attaching a typical 5 shot group I get from my well used '41 Tula original sniper. Bore is only fair and the stock has two pins in the wrist to stabilize a bad crack. I did have to put some (removable) gasket paper shims in to tighten up the receiver-stock fit. Just about every group I shoot with it has 3 shots within an inch and a couple that open it up a bit. The trigger is pretty bad. Note that this is with PRVI 182 grain FMJ. Some feel the heavy ball ammo is bad for these but I figure since I'm shooting fairly small volumes for accuracy it probably won't hurt. For hunting purposes you might consider some of the commercial offerings.

milsurpo
 
milsurpo said:
Rayleigh S.: What exactly is "signature management"? Not familiar with that one! A properly functioning SVT 40 should be able to give you perfectly adequate precision for hunting. I should have asked before if you have managed to get it perfectly zeroed? I have one that was shooting 2 ft low and to the left as purchased (right fresh from refurb). A session with a good bench where you can really establish some baselines would probably be very helpful at this point. I'm attaching a typical 5 shot group I get from my well used '41 Tula original sniper. Bore is only fair and the stock has two pins in the wrist to stabilize a bad crack. I did have to put some (removable) gasket paper shims in to tighten up the receiver-stock fit. Just about every group I shoot with it has 3 shots within an inch and a couple that open it up a bit. The trigger is pretty bad. Note that this is with PRVI 182 grain FMJ. Some feel the heavy ball ammo is bad for these but I figure since I'm shooting fairly small volumes for accuracy it probably won't hurt. For hunting purposes you might consider some of the commercial offerings.

milsurpo
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>should be able to give you perfectly adequate precision for hunting

I believe that. If the problems I had were due to the rifle it would never have entered service, no matter how loudly the Wehrmacht was banging on the doors of the Kremlin.

I must develop my skills.

>signature management

How I manage my visual/audio/scent signature. I had much cause to ponder it while watching other groups of deer receding into the distance, although I am likely using the wrong term for it when applied to people (rather than platforms).

I was stationary, down-wind, a not-conspicuously-different colour, not readily identifiable as human-shaped due to crouch and partial concealment, face shaded by the hood, and had a strong wind to mask incidental sounds. Some of that was planned, some was luck. I come to understand that most of it is technique and perception.

It just occurred to me that there was plenty of tall grass between me and my intended victim, and that I was firing the lightest and fastest projectiles I have ever used. And my horizontal error did seem to be worse than the vertical one.
 
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OP, was it just grass or were there any little saplings in the mix? I ask because at that range a bullet will buck some standing grass without to much affect provided its not to thick, from my experience anyway. Whereas hit one tiny branch and it's game over.
 
JDForBrkFst said:
OP, was it just grass or were there any little saplings in the mix? I ask because at that range a bullet will buck some standing grass without to much affect provided its not to thick, from my experience anyway. Whereas hit one tiny branch and it's game over.
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>one tiny branch

Lots of big macho prairie range grass, but no bushes that I remember. My memory image of the animal has it appearing up out of an even "grass sea" at about the elbow, which was level with my point of aim.
 
Hmm, I've shot through tall grass before at ranges out to 300 without much if any notable effect. But, the closer to the muzzle the greater the effect. You can shoot through even small branches if they are very close to your target without much ill effect on POI, close to the muzzle though, or even half way between, forget about it. A lot of grass, especially if close to the muzzle can make a mess of things. If it's only some, and if it's green, you can get away with a surprising amount. It's one thing most hunters would hugely benefit from is shooting through different vegetations at different distances between shooter and target. Can learn a lot about what you can and can't get away with. I was fortunate enough to have the opportunity to do it on the tax payers dime. End of the day, if you haven't practiced it, don't shoot through anything except your target.
 
I think there is no real way around it, just have to go to the 100 yard range and shoot some sample 5 round groups off a solid rest.
Post the resulting targets photos here and then no doubt many experienced folks can provide you with some concrete input.
 
>range

Agreed. There's no substitute for real rounds down range.

And keeping in mind the excellent info posted by the wise folks above.

First I'll see how she works off the bench.

Btw: any suggestions on how to keep the brass a bit closer to home plate?
 
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