SVT Scope Mount Troubles...

M

matthunt101

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So I'm having a problem with my SVT repro scope mount, it no longer stays forward and on the rifle upon firing. Hopefully one of you guys will know of a way to fix this. I'm thinking about getting a new cross-pin machined and get it made a little deeper so it will fit more snuggly onto the rifle and hopefully not move. This will however require me to also file the slot on the mount bigger to accommodate the new cross-pin. However before I do this, I was hoping someone here might have a better idea/solution.


As you can see the pin seems to have pushed some metal from the receiver back and it is now able to ramp up over the lip of the groove.

Wear on the cross pin.

The cross-pin in the mount. It seems like it needs to be a little lower.

Thanks in advance.
:cheers:
 
This is exactly why Soviets abandoned svt40 sniper rifles in favor of Mosin. Once the pin is wearing the receiver, the whole mount becomes lose and scope is no longer holds zero.
Unfortunately there is no way of fixing this unless you weld up the receiver and re cut the groove. Or as you said it, you will need bigger pin and bigger hole in the mount.
 
gewehr76 said:
This is exactly why Soviets abandoned svt40 sniper rifles in favor of Mosin. Once the pin is wearing the receiver, the whole mount becomes lose and scope is no longer holds zero.
Unfortunately there is no way of fixing this unless you weld up the receiver and re cut the groove. Or as you said it, you will need bigger pin and bigger hole in the mount.
Click to expand...

This is pretty much what I fingured...Although welding the receiver is something I may look into. I've also considered using some JB Weld on the pin itself to make the pin slightly large, but I'm unsure how long it would last.

DILLIGAF said:
I used Devcon to bed the pin in place as well as in the groves.

My scope mount has yet to move in 1000+ rounds
Click to expand...
I assume you're talking about their epoxy? I'm also not sure if this would help me fix my problem, but than again if I can force the pin a mm lower it may be enough to get me through for a little while. Where does one buy Devcon?
 
gewehr76 said:
This is exactly why Soviets abandoned svt40 sniper rifles in favor of Mosin. Once the pin is wearing the receiver, the whole mount becomes lose and scope is no longer holds zero.
Unfortunately there is no way of fixing this unless you weld up the receiver and re cut the groove. Or as you said it, you will need bigger pin and bigger hole in the mount.
Click to expand...

Exactly
 
I had the same trouble with mine and ended up filing the hole for the cross pin out deeper so it is now in line with the notch in the receiver.
Made a new locking pin for it and now it does not move at all any more .
Another problem with this POS aftermarket mount was that the scope would not zero,I had to shim the back end up with brass shims,but it still would not get even close.
Finally I got so mad that (after doing some careful measuring with a dial indicator) I put it under the shop press and pressed the support down.It should be pretty close now,just waiting for some nicer weather to take it to the range and try it out.
.
 
Butcherbill said:
Can you put a metal sleeve over the section of pin that is in the notch?
Click to expand...

Certainly something to think about.

With that said I was just in contact with Martin from Corwin-Arms, and apparently he's going to have some sort of adaptor coming in soon so that you no longer need to file down the receiver. So I'm going to look into that as well.

M1-Garand said:
I had the same trouble with mine and ended up filing the hole for the cross pin out deeper so it is now in line with the notch in the receiver.
Made a new locking pin for it and now it does not move at all any more .
Another problem with this POS aftermarket mount was that the scope would not zero,I had to shim the back end up with brass shims,but it still would not get even close.
Finally I got so mad that (after doing some careful measuring with a dial indicator) I put it under the shop press and pressed the support down.It should be pretty close now,just waiting for some nicer weather to take it to the range and try it out.
.
Click to expand...

Any chance you could PM me some pics of your handy work? Also, how much bigger did you need to make the pin?

:cheers:
 
Not much to be seen in a picture,how far down you have to file the hole depends on how deep the notch in the receiver is.
The notch in my receiver I machined it myself in the milling machine so it looks very neat.
Then I took the spring etc.out of the mount and slid it on the receiver so it would line up with the notch and estimated how much to file the hole out so the bottom of the
hole would be in line with the bottom of the notch.
Then took the mount of and started filing witch a small round file and kept measuring that I filed an even amount off on both sides.
When that worked out OK I made a new oblong pin,of course without the spring loaded thingy in it and Bob's your Uncle,it fits like a glove now,no more movement with the spring loaded plunger installed back into the mount.The oblong pin on mine measures 6.9 mm from the flat top to the rounded bottom.
Hope this will help you,
Herman
 
gewehr76 said:
This is exactly why Soviets abandoned svt40 sniper rifles in favor of Mosin. Once the pin is wearing the receiver, the whole mount becomes lose and scope is no longer holds zero.
Unfortunately there is no way of fixing this unless you weld up the receiver and re cut the groove. Or as you said it, you will need bigger pin and bigger hole in the mount.
Click to expand...

I don't know about this- never seen a badly (or even slightly) damaged notch on a real, original sniper SVT. So either they were never used as a sniper rifle or the real, original mounts actually fit (more likely). The mounts appear to be designed to dampen recoil with the mount moving forward, compressing the spring on firing, and then sliding back into battery. With the 3 replica mounts I've had the pin is much too high up above the receiver and the damage occurs. It's easy enough to shape a copper or brass insert that takes the recoil and protects the receiver. Back to the history, the real main reason that the SVT failed as a sniper rifle was accuracy! It was observed that the first shot from a full magazine might strike many MOA away from the remaining shots- which might group alright. Not being able to rely on the first shot going where intended obviously reduced their value as a sniper rifle.

milsurpo
 
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milsurpo said:
I don't know about this- never seen a badly (or even slightly) damaged notch on a real, original sniper SVT. So either they were never used as a sniper rifle or the real, original mounts actually fit (more likely). The mounts appear to be designed to dampen recoil with the mount moving forward, compressing the spring on firing, and then sliding back into battery. With the 3 replica mounts I've had the pin is much too high up above the receiver and the damage occurs. It's easy enough to shape a copper or brass insert that takes the recoil and protects the receiver. Back to the history, the real main reason that the SVT failed as a sniper rifle was accuracy! It was observed that the first shot from a full magazine might strike many MOA away from the remaining shots- which might group alright. Not being able to rely on the first shot going where intended obviously reduced their value as a sniper rifle.

milsurpo
Click to expand...

Absolutely there were other issues with SVT in sniper role, than just that pin and receiver issue. Its just that its harder to shoot semi auto rifle accurately than bolt action. Shooter has to do his part every time he pulls the trigger. This is evident in the process of zeroing the rifle. As per manual- when new rifle is accepted in to service it has to be shot at targets of certain size at 100m with sights set at 3, and the most important part of it is that it had to be done by best shooters in the batallion. So after 4 shots fired, if holes are within 15cm radius of each other it was deemed acceptable and rifle was zeroed, then issued to trooper who would be using it.
So If this was the only issue, then they would come up with side mount or other means of mounting the scope
 
matthunt101 said:
Thank you very much. Should make my life a little easier.
Click to expand...

Don't listen to BS about the SVT mount system was the reason rifle failed as sniper. There are no evidences of it. Authentic snipers with authentic mounts did not have issues of holding zero, and there were no notch damage. Original sniper issues were overall accuracy worse than bolt rifle and some rifles having "1st flyer" issue. That's it. It did not fail, just better and cheaper solution was adopted.
Issues you're having is because repro mount is out of specs. Too high. Two solutions were already offered. Lower the hole in the mount and made custom pin to fit bigger hole. Second one is to use brass sleeve in the notch, effectively raising it up to the level of cross pin. Brass also takes some damage and keeps notch from further deformation. That is what I use on my sniper. You'll have to change sleeve from time to time, I made mine from .45 brass I picked at range.
Also note - your rifle is not authentic sniper so there's a chance it will not be very well aligned with mound axis. Repro mounts themselves are of different qualities, some sit just high, some even higher. Mount also could be not very well aligned with its rails. Mount might not hold tight, I had to squeeze mine in vice to make it sit tight on the rifle.
 
DILLIGAF said:
I used Devcon to bed the pin in place as well as in the groves.

My scope mount has yet to move in 1000+ rounds
Click to expand...

Do you mean Devcon can fill the gap and hold the pin and actually prevent the damage? It just polymer, how could it be? Maybe you already have perfect alignment of pin and the notch?
 
Horilka said:
Don't listen to BS about the SVT mount system was the reason rifle failed as sniper. There are no evidences of it. Authentic snipers with authentic mounts did not have issues of holding zero, and there were no notch damage. Original sniper issues were overall accuracy worse than bolt rifle and some rifles having "1st flyer" issue. That's it. It did not fail, just better and cheaper solution was adopted.
Issues you're having is because repro mount is out of specs. Too high. Two solutions were already offered. Lower the hole in the mount and made custom pin to fit bigger hole. Second one is to use brass sleeve in the notch, effectively raising it up to the level of cross pin. Brass also takes some damage and keeps notch from further deformation. That is what I use on my sniper. You'll have to change sleeve from time to time, I made mine from .45 brass I picked at range.
Also note - your rifle is not authentic sniper so there's a chance it will not be very well aligned with mound axis. Repro mounts themselves are of different qualities, some sit just high, some even higher. Mount also could be not very well aligned with its rails. Mount might not hold tight, I had to squeeze mine in vice to make it sit tight on the rifle.
Click to expand...

I'm inclined to agree with you, the mosin was simply cheaper and just as effective in sniper role. I've never had an issue with first round flyer with my rifle thankfully, and have gotten reasonable accuracy out of my rifle. My only issues are like you said, the mount is slightly out of spec, the notch is too high and the mount centers a few mm to the left of the barrel axis.
I think I'm going to try out the brass sleeve while I wait to get the new pin made. Worst case it won't work for me and I'm no worse off than before, best case it works until I am able to get the pin made and file the hole bigger.
Thanks for the advice and help.
:cheers:
 
So here's a little update, after reading all the suggestions above, I made this little spacer last night out of an old casing I had lying around. As you can tell the workmanship isn't fantastic but since it only took me about a half hour I think it's pretty good. I'm hoping this will provide enough grip onto the receiver so that the scope will stop sliding off the back. I'm hoping to get to the range on Sunday, so hopefully I'll be able to provide a report of whether or not it worked Sunday night.
:cheers:


 
So just thought I'd update this thread even if it is a little bit later than I had intended. Had it out to the range last weekend and the addition of the brass seems to have fixed my troubles. Everything stayed rock solid was quite happy to say the least.

:cheers:
 
Horilka said:
Glad it worked for you.
Click to expand...

Me too! haha
I had to adjust the zero on my scope slightly, and I'm still a little off, but I'm very happy with the result so far. It didn't move at all while I shot it and the recoil forced the shape of the brass to fit a little better. I'm actually getting better groups now than when I first got the scope and it was fitting "well".
Still planning on getting a new cross pin made eventually though. Just waiting for the machine shop at school to slow down a little bit....
:cheers:
 
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