Protecting SVT 40 receiver notch with repro mount
Results 1 to 27 of 27

Thread: Protecting SVT 40 receiver notch with repro mount

  1. #1
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default Protecting SVT 40 receiver notch with repro mount

    About to head to the range this week with this '42 original (but refurbed) sniper rifle. No luck with accuracy with this one yet so have done some shimming to tighten up the receiver-wood fit. Also had to make a new copper insert for the notch to avoid damaging it. The side view of the copper piece shows how poorly this repro mount is dimensioned. With the insert in place the mount cross pin is a sliding fit and if used without insert the rounded pin will slam against the top rear of the notch and deform it. I used copper as it is soft enough to expand and stick firmly in the notch. No idea who manufactured this mount as it has no markings but all 3 of the ones I've purchased have the same problem. If you use a repro mount check the fit of the pin as the notch can be pounded out of shape very easily.

    Ruprecht
    Attached Thumbnails Attached Thumbnails DSCN4861.JPG   DSCN4863.JPG   DSCN4867.jpg  

  2. #2
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    4,287

    Default

    Why would the pin slam against the rear of the slot? The recoil should cause the rifle to move rearward, while the scope wants to stay put, putting pressure on the front of the notch if any.

    Have you checked your side to side play? That was the issue I had to remedy for the reproduction mount on my ex-sniper. Also, the plunger springs are too weak.

  3. #3
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    jjjxlr8: The rather stiff spring in the mount compresses on recoil then drives the mount back against the notch. I've never seen any evidence of the pin touching the front of the notch- just the rear. No detectable side to side play on mine and, surprisingly, the axes of the 3 repro mounts are all well aligned with the bore on my 4 original snipers. Not the case with other non-snipers I've slipped the mounts onto and tried to boresight. I'd be very curious to hear if others have found repro mounts that don't have this problem with the pin height.

    Ruprecht

  4. Remove Advertisements
    GunBoards.com
    Advertisements
     

  5. #4
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    4,287

    Default

    Yeah, I guess the mount makes contact with the cleaning rod door at the back of the receiver before the cross-pin ever could hit the front of the notch. The cross-pin does sit a bit higher than it needs to. I see marks on my cross-pin more than on the receiver notch, though. I might try the shim idea to see if it improves contact on mine.

    Thanks!

    Do you have a picture of your plunger spring?

  6. #5
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    4,287

    Default

    Here's a photo of the reproduction ("Finnbear") mount pin vs. original. CH posted a really good comparison of these 'fake' mounts vs. original a few years back and this photo is his. Notice how much larger the original pin is.

    Attachment 1897449

  7. #6
    Join Date
    Nov 2008
    Location
    USA
    Posts
    2,520

    Default

    Interested in hearing more on how your rifle shoots with the copper insert and other shims. I have a 1941 SVT sniper that I want to get up and running.

    Thanks,
    PA
    Looking for PU scope number 10062. See post http://forums.gunboards.com/showthre...light=pashutr3

  8. #7
    Join Date
    Dec 1969
    Posts
    1,410

    Default

    I have shot SVT Snipers for years with original and Finnbear mounts (some of Finnbears were real) as were the ones we bought in Finland. I have also inspected real & fake notches on many rifles. I have never observed any metal distortion in either direction of the notch. Think you are seeking a solution for a non existent problem. (I am sure I will hear about this comment.) Skid

  9. #8
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Quote Originally Posted by sssniper View Post
    I have shot SVT Snipers for years with original and Finnbear mounts (some of Finnbears were real) as were the ones we bought in Finland.
    I have no doubt the originals were properly sized or that there may be some repro's that fit. I also have no doubt that others have run into the problem I have with these junky repros currently being sold here in Canada. I have a '41 refurb sniper rifle that now has a deformed notch due to this and I suspect other owners would prefer not to damage the one (superficially) visible feature that distinguishes them as genuine.

    Ruprecht

  10. #9
    Join Date
    Dec 1969
    Location
    NC
    Posts
    11,450

    Default

    I think the deformation problem is bigger than the repro mount and pin. It is multi-factorial IMO. The springs are not the same, the ones that preload the mount. The key/lock is inferior on every repro in my experience. Some do not carefully pre-load the mount but do drive in the key. Original keys and mounts must have been fitted to the rifle, the mounts are numbered after all. The repros are surely not hand fitted. Repro metal quality is just inferior. All variables just sets the person with and original notched sniper for deformation of the notch if they shoot it.

    I have had six and all had a little damage/deformation to the original notch. The originals were not what they hoped them to be and the repros are just not gonna do a perfect job when you shoot them. JMO.

    I do think trying to make the fit of the mount and rifle as near perfect as possible, using shims or whatever, is a noble cause and should help accuracy. It is a real shame the original mounts were scraped, lost, tossed, whatever. We would know much more if they were still around along with their original rifles.

  11. #10
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Mike: about 4 years ago, just as I was getting into SVT 40's, an original (apparently) mount came up on e-bay listed at around $1000.00. I passed on it thinking that there had to be a few out there- man was I wrong! Haven't personally seen another for sale since- other than battlefield relics. Soft shims like the one I show don't last long but do protect the receiver and I don't tend to put a lot of rounds through my sniper SVT's anyway. I've only had 2 of my 4 to the range so-far and the '41 is as accurate as my No. 4 T's as long as I concentrate real hard on the trigger pull. The '42 shown in post #1 was horrible during its first test in spite of a better bore. Getting back to the mounts, it is unfortunate that the pin height is too high- certainly can't be explained by variance in the notches on the sniper rifles. The notches on my 4 are identical in terms of fore/ aft position on the receiver and height of the flat bottom of the notch above the side-rails that locate the mount.

    Ruprecht

  12. #11
    Join Date
    Jan 2010
    Location
    Colorado
    Posts
    206

    Default

    Ruprecht, I believe you are spot on as I have had the SAME problem with my original sniper and repro (Sarco) mount and pin. The pin bashed the back of the notch and just catches the top edge of it. I like your solution! Want to make another one and sell it?? I would buy that in a heartbeat.
    By chance did your copper shim help the accuracy?
    Bill

  13. #12
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    HeavyB: Based on tests with brass insert and my '41, accuracy seems to be unchanged with the mount now no longer free to move back and forth. Not sure why the original designers felt the scope/ mount needed to have this feature (buffer?)- the recoil with 6 port muzzle break is pretty mild. It was a pretty tedious job filing the insert and I need to see how many rounds it will stand up to given how soft copper is. What kind of accuracy have you seen out of yours?

    Ruprecht

  14. #13
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    4,287

    sick

    Maybe the repro mounts were designed this way so that the owners don't have to file such a deep notch in their receivers. The market is pretty small based on the number of ex snipers out there. There are lots of railed non sniper SVTs though!

  15. #14
    Join Date
    Jan 2010
    Location
    Colorado
    Posts
    206

    Default

    You know I started to think that the amount of time it took to shape out the brass probably makes it tough to want to make one for someone else - so please disregard the comment of selling one, I will spare you and do it myself haha! But I like your idea - I think that is a good solution.
    Mine will give 2 to 2.5" groups at 100 yards with ideal conditions, but after that barrel gets hot, (maybe 5 or 6 shots) my shots just start stringing left! And noticeably - dang things will almost walk right off the paper.
    Bill

  16. #15
    Join Date
    Jan 2010
    Location
    Colorado
    Posts
    206

    Default

    jjjxlr8, I TOTALLY agree! They built it to the specs their market needed.

  17. #16
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Quote Originally Posted by jjjxlr8 View Post
    Maybe the repro mounts were designed this way so that the owners don't have to file such a deep notch in their receivers. The market is pretty small based on the number of ex snipers out there. There are lots of railed non sniper SVTs though!
    That's definitely a good point! I have done this myself with a '41 to have a repro "sniper" for plinking and fun shoots. You don't have to do much filing to make it fit. With your prices south of 49 I don't know if I'd be filing one- the one I used cost me all of $200 (Canadian) two Christmases ago. Had planned to break it up for parts but found it to be rather nice and have put many rounds through it in addition to using it for testing different bedding techniques.

    Ruprecht

  18. #17
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default Copper shim works.

    Made it to the range with this '42 a couple of weekends ago. The copper insert worked perfectly- it stayed put and completely protected the receiver notch through 60 rounds of Chinese light ball. I had only tested this rifle with commercial heavy bullet FMJ prior to this outing and with the heavy stuff it wouldn't keep 5 within a foot. I've shown one of the better results from this trip which, while a big improvement, is still pretty poor but note 3 shots in an inch (two almost on top of one another). I've had similar results with several SVT's- 2-4 inch groups but very often 3 in an inch or less. This isn't the first shot flyer phenomonon commonly attributed to the SVT as I've often noticed the tightly spaced rounds at the start of a group.

    On another note, I'm curious to see if anyone else has noticed the following: while increasing the gas setting from 1.2 to 1.3 to 1.5, during this shoot, I noticed the POI drop at least a foot. To me this suggests that the force with which the cyclinder/rod, etc are driven back is directly affecting the orientation of the muzzle at exit of bullet. Is that possible? The gas port is about 4.3 inches from the muzzle and the operating rod typically has about 0.050inch play before the bolt carrier mass is taken up. It doesn't take many milliseconds for the bullet to get from port to muzzle- is it long enough for the operating rod to push the muzzle down and affect the bullet path? It's worth noting that another gas op. rifle with accuracy issues (G43/K43) has gas tap even further from muzzle.

    This particular rifle came from refurb with fully floated barrel with what I would call a fair bore. I've shimmed at rear of receiver and between spring and triggerguard tang (to increase the clamping pressure). As you can see it's in a good condition heavy later stock. I don't know if it's possible but the date beside the star almost looks like '42 to me.

    Ruprecht
    Attached Thumbnails Attached Thumbnails DSCN4883.jpg   DSCN4884.jpg   DSCN4885.jpg   DSCN4886.jpg   DSCN4869small.jpg  

  19. #18
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    4,287

    Default

    The POI is affected as you are bleeding off more gas just before the bullet exits.

  20. #19
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Quote Originally Posted by jjjxlr8 View Post
    The POI is affected as you are bleeding off more gas just before the bullet exits.
    I wondered about that but couldn't believe the affect would be enough to cause the change in POI that I saw at 100 yards.

    Ruprecht

  21. #20
    Join Date
    Dec 1969
    Location
    NC
    Posts
    11,450

    Default

    Solmon had a lot of data and experimentation with a Podosk scoped SVT. He tried floating and other things, various loads, had some great groups(in the one to two MOA range IIRC). Search his posts and hopefully they are still around.

    My best groups with any scoped SVT were a bit over 2 MOA but most are more like 6 MOA on average. The best was an added notch Izhevsk. Four rifles were rifles which were refurbed snipers with original notches and repro mounts. The best mounts were the Finnbear mounts but one cheap mount did very well. My only original mount is a dug mount. It is tight so I am gonna give it a try at some point, on one of my two remaining rifles that were snipers when built but refurbs.

    I am betting an original sniper, even with their shortcomings, was a 2-3 MOA rifle and 3 or 4 of a 5 shot group being much tighter. LP used one for many of her kills. I doubt anyone will be able to test a nice original SVT sniper to get more data. Maybe Ratnik has more statistics??

  22. #21
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Quote Originally Posted by jjjxlr8 View Post
    The POI is affected as you are bleeding off more gas just before the bullet exits.
    jjjxlr8: I tried to test this possibility with a ballistics calculator. For my favorite .303 commercial load it would require a 500 fps drop in MV to have a one foot drop in POI at 300 yard all else being equal. Leaves me doubting that simply changing gas settings could have this order of magnitude of effect at 100 yards with 7.62 x 54. Either explanation, as a sniper no way you would change the gas after zeroing.

    Mike R: My best ever group with a genuine SVT sniper ('41, well worn bore, stock with two pins at the wrist) has all 5 within or touching a 1.5 inch square. 3 out of the 5 are in a 0.80 inch group. On another occasion, with that rifle, shots 1-3 formed a 0.75 inch group. Shot "4" doubled with #4 being 6 inches high and #5 in the bank behind the target. The trigger mechanism (maybe combined with how I'm holding it) with that one seems to be the reason for occasional doubles but I do think the rather horrible pulls on the SVT contribute a lot to the precision problems. I hate going from something with an excellent trigger to an SVT during a range session.

    Like you say, no one will probably ever get a chance to rest a like-new SVT sniper. My 4 have poor to fair bores and are refurbs so may have original barrels but little else. The best I could do would be to take one of my non-snipers that have pristine bores (I have a few like that) and mount a scope on it.

    Ruprecht

  23. #22
    Join Date
    Aug 2012
    Posts
    247

    Default Barnaul 174gr, happy, happy, notch protector works so far!

    I know cleaning an SVT is not that difficult, read that everywhere. I HATE the recoil spring assembly. I have large arthritic hands and dealing with that assembly is not easy for me at all. So I have looked for some non-corrosive ammo to use in my original 41 SVT sniper. My gunsmith made up some notch protectors from photos I provided. Took it to the range, got 2-3" groups at 100yds. Probably can do better once I develop a better bench technique for that long, wiggly forearm/barrel. This particular SVT has a dark barrel. (I have 2 others with much nicer bores, that's why I am shooting this one!)

    Rifles groups almost as good as those I get with my least accurate M305 (Chinese M1a) and Hirtenberger surplus ball ammo.

    The notch protector works so far, but very few rounds fired so far.

    Barnaul 174 cycled nicely at 1.3, not particularly dirty, works for me.

  24. #23
    Join Date
    Feb 2008
    Location
    Ohio
    Posts
    4,287

    Default

    Quote Originally Posted by kujuak View Post
    I know cleaning an SVT is not that difficult, read that everywhere. I HATE the recoil spring assembly. I have large arthritic hands and dealing with that assembly is not easy for me at all. So I have looked for some non-corrosive ammo to use in my original 41 SVT sniper. My gunsmith made up some notch protectors from photos I provided. Took it to the range, got 2-3" groups at 100yds. Probably can do better once I develop a better bench technique for that long, wiggly forearm/barrel. This particular SVT has a dark barrel. (I have 2 others with much nicer bores, that's why I am shooting this one!)

    Rifles groups almost as good as those I get with my least accurate M305 (Chinese M1a) and Hirtenberger surplus ball ammo.

    The notch protector works so far, but very few rounds fired so far.

    Barnaul 174 cycled nicely at 1.3, not particularly dirty, works for me.
    Have you ever tried using a cartridge to hold the spring assembly?


  25. #24
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Yes, Kujuak, as jjjxlr8 says, use of the cartridge makes disassembly and reassembly very easy. The cartridge also can be used to release the triggergroup and to release the upper band. Note that there are some dustcovers that won't lift out of the receiver when pushed back the length of a cartridge but these are rare- I,ve only found one on a simplified, flat backed Podolsk.

    Ruprecht

  26. #25
    Join Date
    Nov 2008
    Location
    USA
    Posts
    2,520

    Default

    Thanks for the additional info and range report.

    PA
    Looking for PU scope number 10062. See post http://forums.gunboards.com/showthre...light=pashutr3

  27. #26
    Join Date
    Apr 2014
    Location
    Calgary, Alberta
    Posts
    639

    Default

    Quote Originally Posted by PAshutr3 View Post
    Thanks for the additional info and range report.
    PA
    PAshutr3: Let us know how your '41 works when you get it up and running. Regards.

    Ruprecht

  28. #27
    Join Date
    Aug 2012
    Posts
    247

    Default but of course! still a P.I.A.

    Quote Originally Posted by jjjxlr8 View Post
    Have you ever tried using a cartridge to hold the spring assembly?

    That is the method I always use. It still would take 3 hands, one with "spider fingers" for me to find the process easy and to do this without ending up with bandaids on my thumb. Thanks for the suggestion.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •