SVT40- accuracy controls

[Ridolpho]

I'm curious about the anecdotal stories of accuracy problems including wildly errant first shot so I decided to begin a little accuracy test of my own examples. For starters I thought I'd strip each of the four and attempt to see how the action/ barrel are bedded in these refurbs. The rifles are Tulas (two 41's, one '42, and one '44). Two have the groove at top of the bolt cover and are probable original snipers. All have very well preserved metal surfaces and show signs of quality work in the refurb. To be brief, all four show consistant bedding points as shown on the photo. With the stock installed all four have significant (5 lb+) up-pressure at the tip of the stock. This pressure is either entirely on the ring in the lower metal jacket or, in one rifle, on both metal and about one inch of the wood. I don't believe the metal jacket assembly is rigid enough to impart any up-pressure at its tip but, rather, will flex as the barrel oscillates. The cleaning rod is also "along for the ride". Rearward, the barrel to barrel re-inforce are free while the receiver ring and small flat forward of the cross-pin bear on the stock. Of great interest to me, three of the four display absolutely zero longitudinal free-play of action in stock with cross-pin and trigger assembly inplace. The fourth (a non-sniper) has considerable free-play (at least 0.008") which is what I get the impression some feel could lead to the big spread between first and second shots and which could be solved with shims. To me, the biggest unknown seems to be the effect of all the junk hanging on the front of the barrel (ie. forward of the tip of the stock). These parts are probably highly variable in fit from gun to gun. So, question to the accurizing gurus out there: How well thought out is the position of the stock-end up-pressure from a barrel oscillation point of view and what approaches might be worth considering for optimizing one of these rifles? I plan to take a couple to the range this weekend to start some tests. Love the design- simple, logical.

Ridolpho

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[jmoore]

You may be a trail blazer on the subject, at least in this hemisphere. I'm down to two and a few spare parts. Both are Finnish captures, so no Post-WWII rework. Looking forward to your findings!

[WarPig1976]

Good thread, looking forward to the results..


The soldier above all others prays for peace, for it is the soldier who must suffer and bear the deepest wounds and scars of war.

Douglas MacArthur

[Ridolpho]

Thank's guys. I'll be hitting the range tomorrow (Saturday) with a big pile of quality commercial ammo. Sunday we may get our first big snow of the season. I wish there was more written (in english) on the SVT38/40 but all it has received so far seems to be passing (but useful) mention in books about other rifles (for example, in "Hitler's Garands" by Weaver). Has anyone out there any knowledge about books in Russian that might exist- I've recently tracked down a Russian language prof. at the local University.

Ridolpho

[Ridolpho]

jmoore: I forgot to ask- what, if any, repairs or changes did the Finlanders make to your two rifles?

Ridolpho

[jmoore]

They did nothing more than mix some parts and add the SA mark, as far as I can tell. One is matching except for the trigger group, the other may have a few other mismatched parts, but both keep the parts to the same mfg.

[Ridolpho]

Well, I can see this is going to be a lot tougher than I thought. Made it to the range with two rifles but ended up only shooting one ('42 Tula with sniper notch). This gun has very tight action body fit- no detectable free play but bore is only fair with dark, slightly pitted grooves/ decent rifling overall. The rest of the mechanicals look hardly used post refurb so strange the bore is as it is. Unfortunately the gun was not zeroed (way off) and the equipment I had with me wasn't up to the job of drifting the front leaf. Forced me to hold off to right on the targets I had which, I might say, weren't much good for these open sights. Then I had to play with the gas setting to get it cycling (totally reliable on 1.3). Main fact about this gun is long, heavy trigger pull- one of the worst I've run into. Photos show the two best (aargh) 100m 5 shot groups of the day. The one on the right is about 5 inches, the one on the left has 3 shots in about 1.25 inch and a fourth pulled and a fifth......? It slam-fired after number 4 and probably went well above the target. Went to put the scope on for a few groups only to find I'd misplaced the pin. End of session. The ammo that I used was "WPA" steel-case, 174gr fmj. It's my intention to establish typical groups with all four (well, now it's five) of my SVT's which have a variety of action fit, bore condition, trigger pull, etc. Three of the five will hold a scope and these will be shot both scoped and over the iron sights. Might try a few experiments like shooting without cleaning rod/ metal guards, shimming loose action bodies, etc. I'll revive this thread in a month or two when I've finished. You might want to buy stock in "WPA".

Ridolpho

[jmoore]

I figured out how to lighten the trigger pull, but it requires relocating the spring seat on the sear. It's the strangest firing mechanism! If you go swapping trigger groups, watch that the disconnector pin in the receiver engages properly the safety bent at the front of the pack. Very often it won't work right without fitting.

[jjjxlr8]

There are a few slow motion videos of the SVT40 firing that might give you a hint as to what pressure points might be more important..

I think this is one but I'm unable to view it right now.

[WarPig1976]

There are a few slow motion videos of the SVT40 firing that might give you a hint as to what pressure points might be more important..

I think this is one but I'm unable to view it right now.

Yup, that's the one..