Unertl scope - losing zero

[Bradley Albrant]

Hello all, I recently got a Springfield 1903 with a vintage Unertl scope on it (12x). I had sighted this in at 100 yards and it seemed to hold well.

Upon using it up north and having accuracy issues I checked it with a bore sight to learn the scope was now upwards of 2" off at just 15 yards.

Do these scopes normally have issues holding zero? Can anything be done to prevent such a large shift?

 

[Hecouldgoalltheway]

Carlos hathcock used to use them to shoot fleas off mice at 1.3 miles with ball ammo after crawling through the jungle for 3 days alone on a suicide mission that he always survived. They can't be that bad.

 

[Aftermath]

@pmclaine

 

[pmclaine]

Your bases are tight? The mounts are holding tight in the bases? Your mounts are correct for the bases? the plunger is moving properly in the bore to keep the tube firmly against the turrets? Your pope rib is secure to the tube and the front of the scope is secure in its mount?

Internally there is not much to go wrong that could shift zero. Even the reticle cell is pretty snug in the bore of the tube just forward of the ocular lens piece.

Check all of the above.

 

[Random Guy]

The tension of the plunger and its related spring needs to be consistent. The mounting screws can come loose too after firing, and after tightening, I put some paint at 12 o'clock so next time I'll know if the front sight knob comes loose...I had windage drifting off in a match years ago...afterwards I noted that the front mounting screw was slightly loose.

 

[Charger442]

are you returning your scope to battery position if you are not using a recoil spring to do it for you?


check all mount screws and lube the plunger. make sure that one of the turret knobs isnt stripped.

they are rock solid scopes and mounts, for their age. id be concerned until i found what should be an obvious culprit.

 

[fa38]

If you are shooting issue type ammunition and the sight has a recoil spring I would either take the spring off or set it so that the scope sort of free recoils to the point that you have to pull it back for each shot. Pulling it back each time becomes sort of automatic.

You may have a loose crosshair. Look thru the scope and give the scope a light hit with a cartridge case. If one of the crosshairs moves you could take the crosshair cell out and carefully, very carefully put a small drop of glue on the anchor points. Its easy to wreck both crosshairs. I had a Unertl that had a loose vertical wire and the glue job worked.

 

[billy1946]

I have built 4 clones 1903 using Unertl scopes and have never had a problem with holding zero. This on with a clone Unertl.