(repro) 91/30 PU sniper rifle initial sighting in and zeroing details ?

[RobSmith]

Bought one of those at a gun show recently, the price was right (could never justify the price of an original). Seems to be well made, built on a 1939 tula with repro scope, I assume the mount is probably repro too although it's electropenciled with the rifle's serial # and seems to have a triangle and arrow mark so I wonder if it's a "new old stick" original . Now I need to sight the beast in. I know that this involves playing around with the mount. Does anyone have rough values on how much shimming/filing may be required and just how to do it "right" ? Same with the mount elevation screws, does anyone have rough values of how much movement per turn to expect or anything of that nature ? All of the online sources I have seen so far are rather sketchy on the details of the "proper" procedure to follow so I don't hopelessly mess the thing up.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[vintage hunter]

First thing you need to do is remove the scope and mechanically center the reticle, otherwise you'll just be pi$$ing in the wind and will end up with an off center aiming post once zero'd.
Next go to mosinnagant.net and click on the sniper section and there you'll find a detailed ''how to'' article on zeroing the PU sniper.
Why do you say it's a repro? Sounds like the mount at least could be authentic, the arrow in a triangle is the Izhevsk arsenal mark. Can you post some good pics of the scope, mount and markings on the barrel shank?
I have a Century Arms clone built from a Finnish Tikka 91/30 I'm quite happy with but saw where Classic Firearms still has some refurbed originals for $550 USD. Tempting.

[RobSmith]

PU sniper rifles didn't come into production until 1942 and she is built on a 1939 rifle ... Regardless I like it a lot, the workmanship to my eye at least is quite nice. Bent bolt handle has a bit of discoloration at the weld point but I guess I can polish that up if I wanted to. Screw ends for the mount have been both ground smooth inside the receiver and then reblued, not something you'd expect from shoddy work and something that was quickly put together (not the stuff you see on "ex snipers" with crudely plugged up holes and such). Scope doesn't have any clicks, just like the originals. Bore seems to be a bit on the rough side but them again I haven't given it a good cleaning yet so it might be just dirt and caked up cosmoline. Stock is hardwood wartime variety. Even the trigger is by far the best I have yet seen on a mosin, literally zero slack and a clean, relatively light break, no grit or creep whatsoever (tells me somebody's probably spent some time working on it too).The thing is both visually and mechanically identical to an original except for the markings. Already put the scope dials at zero all around and the reticle looks nice and centered, when I center the reticle in the field of view I come up with elevation value of 9 and windage zero which I understand is an "ideal" setting. I read the article you mentioned, like I said I find it a little short on actual details in terms of how much of what does what. I also really don't like the idea of filing down things but that's another matter. I don't have pictures as of yet, will try to take some in a few days, hoping to go shoot her for the first time and see if she naturally points anywhere near where the glass says it's is pointing.

[vintage hunter]

how much of what does what.

This is the best info I've come across on zeroing these things.
Don't remember where but I have read that each graduation mark on the windage drum equals 1 mil(3.6'') @ 100 meters but I've never tried it to see.

Mine had to be shimmed to get the windage right and I found that shimming the base .001'' moved POI about 1'' @ 100 meters but this will probably vary from rifle to rifle. Only way I know to determine elevation screw values is fire a group from a steady rest @ 100 meters then turn the screws 1/4 turn, fire another group and measure the shift in POI. Multiply by 4 for a full turn.
As for filing things goes that's how it was done with the originals during set up. Good luck.

[RobSmith]

The repro scope that I have doesn't have graduations in the classic sense, just numbers that go up to 13 and indicate the BDC range the range indicated in hundreds of meters. Judging by how much the gap between numbers increases as the range increases I'd say it should be pretty close.

[mike radford]

One advantage in getting a real refurbished PU is that there is little chance they will need any major change in the settings they left the factory with. They should need no shim nor grind. You may have a factory replica and most of those are roughly factory zeroed with average light ball also.

I bore sight at 100 yds, the old fashion way, bolt out and look down the bore. Adjust the scope to equal the bore picture while keeping the rifle as steady on bags or rest as possible. If you get weird numbers on your scope once this is done you will have a much longer process. If the windage is weird, you may have the big hassle of grind or shim depending. If elevation is odd you can adjust the elevation screws on the mount base so it reads 1 with the bore sight.

Great rifles and well worth owning a real PU while the price is a steal. No other WW2 sniper can be had for less than about ten times as much.