Rifle Scopes mounted new scope-14 mils for 100yd zero? Update

[robdes]

I took a new gun to the range yesterday. POF P-308 with a PRH 3-15 with 1.4" high rings. It took a full turn of the elevation knob to get the scope zeroed at 100. So it was shooting 14ish mils low. Did I just loose 1/2 of the travel of my scope? Is something wrong that I am not thinking of?

BTW- the POF is sweet. I am a shitty shot. The wind was howling and I was all shaky on starbucks. Getting under 1moa was easy.

 

[Pete E]

Re: mounted new scope- 14 mils to get 100yd zero?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dtac</div><div class="ubbcode-body">I took a new gun to the range yesterday. POF P-308 with a PRH 3-15 with 1.4" high rings. It took a full turn of the elevation knob to get the scope zeroed at 100. So it was shooting 14ish mils low. Did I just loose 1/2 of the travel of my scope? Is something wrong that I am not thinking of?

BTW- the POF is sweet. I am a shitty shot. The wind was howling and I was all shaky on starbucks and getting under 1moa was easy. </div></div>

Was the reticule optically centered in the scope before you started? If so, I would say you have a potential problem...

 

[robdes]

Re: mounted new scope- 14 mils to get 100yd zero?

I'm not sure what you mean. The crosshairs were and are in the center of the scope "picture".

 

[Pete E]

Re: mounted new scope- 14 mils to get 100yd zero?

What I mean is that when you buy a scope, the reticule is not always "centered"...So instead of having say 10MOA travel up and 10 MOA travel down, somebody has been fiddling with the turrets and left it such that you now have 15MOA down but only 5MOA up..

So usually before you mount a scope you check that the reticule is centred so you have equal travel up or down, and left and right..Its not essential, but it gives you a good starting point to work out any problems that might occur during zeroing, ie like you have now...

Regards,

Peter

 

[robdes]

Re: mounted new scope- 14 mils to get 100yd zero?

Ahh- I sure hope that was it. The fact that it took me exactly one turn makes me think that is what happened.

 

[michaelt454]

Re: mounted new scope- 14 mils to get 100yd zero?

How many mils do you have left of up travel?

 

[robdes]

Re: mounted new scope- 14 mils to get 100yd zero?

I have 13.5 mils left. The scope is a single turn with 14 mils of adjustment on the knob. When I zeroed it, I used of the entire 14 mils and then reset the elevation knob. So know, I can only turn the knob to 13.5 and not to 14. That should be enough, but it is just weird.

 

[robdes]

Re: mounted new scope- 14 mils to get 100yd zero?

Is it possible that my rail is not parallel to the barrel?

 

[Switchblade]

Re: mounted new scope- 14 mils to get 100yd zero?

First:
Break in your scope's erector's by moving the knobs all the way to lock both ways for at least 20 rotations. Now count from lock to lock so you get a total count of clicks, then come back to center and stop.
Bag your rifle so it is tightly plumb, level, will not move and remove the top half of the rings. Look through the scope as you turn it 180* left and right. If your reticle 'scribes' an arc, move teh scope, and make adjustments to windage and elevation until your reticle is rotating upon it's axis.
Insure your scope is now plumb, level, and where you want it in teh rings. Place the top half of the rings and tighten them up insuring you do not move your reticle or cant it.
You are now mechanically zeroed and can now bore sight at 100M. If all your rails, rings, and mount surfaces are square and tight, you should have no problem getting to zero within a few clicks.

 

[Bobcape]

Re: mounted new scope- 14 mils to get 100yd zero?

<span style="font-family: 'Comic Sans MS'"> <span style="font-size: 11pt"> <span style="color: #3333FF">

There is another way to find the optical center. I used to work for a firearms manufacturer and we got some factory training from Leupold once. They teach a different method. If you place a mirror right against the objective lens and then look through the scope, you will see two crosshair images. Adjust the scope until the images merge into one and the scope is optically centered. I find it easier this way. Both methods will work just fine.

Bob </span> </span> </span>

 

[robdes]

Re: mounted new scope- 14 mils to get 100yd zero?

Update-
Ok, I think I figured it out. The POF rail system uses a number of set screws to locate and level the rail. I seems like one of these was over-tightened and it caused the rail to have a high spot in the center meaning the rail was not flat. the half of the rail over the receiver was not parallel to the barrel. It was like it was a 40moa rail canted in the wrong direction. I think i have the rail straightened out. I'll have a chance to shoot it this weekend- we shall see.

 

[Valken]

Re: mounted new scope- 14 mils to get 100yd zero?

tag