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Rifle Scopes USO ER25 - EREK Knob Questions

BenTerrible

BenTerrible

Which way did my bullet go?
Full Member
Minuteman
May 26, 2009
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I thought I had this thing dialed last week at the range. I just realized I only have 13 mils of actual reticle movement. The allen screw on top will not rotate CCW anymore ( I believe this is what moves the erector? ) The EREK knob will keep turning of course, however, when looking in the scope while doing so I can see the reticle stop when I hit 13 mils.

First question, is this typical? I was under the impression I could get 25 or so mils of elevation. Maybe I have this thing way out of whack?!?!
 

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did you see the instructions on their website?
U.S. OPTICS - Instructions

I had problems with their 1-6 w/erek knob when i first got it too. I didn't know about how the internals worked (especially when comparing to setting and adjusting other scopes). but after seeing this vid, and adjusting it properly...it works well. Good luck
 
I watched the video a few times. It says to bottom the erector screw by turning it CCW while holding the EREK knob. Then to bottom the knob all the way. I had this applied and had to come up lots to find zero.
 
As the scope sits, I can't move the top screw CCW anymore - it is maxed out. I have a 100 meter zero right now. So, in theory I should be able to dial up some elevation with the EREK knob, then bring the reticle back down by turning the top screw CW. This should shift the position of the erector relative to the reticle, giving me more elevation, correct? But then won't my EREK knob index be out of whack in relation to the index scribed on the scope body?
 
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BenTerrible said:
As the scope sits, I can't move the top screw CCW anymore - it is maxed out. I have a 100 meter zero right now. So, in theory I should be able to dial up some elevation with the EREK knob, then bring the reticle back down by turning the top screw CW. This should shift the position of the erector relative to the reticle, giving me more elevation, correct? But then won't my EREK knob index be out of whack in relation to the index scribed on the scope body?
Click to expand...

Ignore the engraving under the knob. It is only for reference. What base are you using? Flat? 20 MOA? 30 MOA?
As it is right now, does the knob stop at your 100M zero, or will it keep going down past it?
 
The EREK system will not give you anymore elevation or defy the laws of physics. What it does is allows the erector assembly to move independently of the elevation knob. If you have your 100yd Zero and you have 13mils of elevation travel; that is what you have. No amount of fiddling with the knob or allen screw will change that. If you want to reclaim more of the travel to elevation then you need a higher canted base. Simple as that.
 
I can dial down a bit from my zero.

Rifle has a 30 MOA rail.

My concern is that I can still dial elevation without reticle movement.
 
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BenTerrible said:
I can dial down a bit from my zero.

Rifle has a 30 MOA rail.

My concern is that I can still dial elevation without reticle movement.
Click to expand...
Lets armchair diagnose this:

-Have you track tested the scope by shooting paper?
-What action is this? What rail? Have you bedded the rail?
-How much Windage from center do you have dialed in?

The fact that you have a 30moa rail, but running about midway in elevation sounds like you're receiver might not be straight. Or if you have windage dialed in to get your zero, you're loosing available elevation as the erector tube is over to one side.

I could be way off base, but from what little I have to go on, this is where I'd be looking.
 
Rifle is the Barrett M98. The 30 MOA rail is machined into the receiver.
 
I used the CS Tactical method at the range but bore sighted it instead of using the magnetic tool. I now have a 100y zero, i can dial down 1 mil from that and have 2 full turns of the erek knob for elevation. The EREK knob was a little scary at first but it works well. Love it.
 
ive got a couple uso 5-25 with the erek

I set the knob first (to the zero stop or a few mils below the zero)

Then i shoot and adjust with erek ( adjusting it up or down with the allen wrench)
When i get it close with that i fine tune it with the knobs and lock it down.

on my creed with a 20moa base, i have over 20 mils up
on my saum with a 30moa, i have 24 or 25 mil up
 
I did just that. I bottomed out the EREK knob, then dialed zero with the allen screw. The EREK knob will continue to elevate well past 13 mils, but the reticle stops moving after 13 mils. I fear the erector is not centered. Need to confirm this with optical bore sighter.
 
BenTerrible said:
I did just that. I bottomed out the EREK knob, then dialed zero with the allen screw. The EREK knob will continue to elevate well past 13 mils, but the reticle stops moving after 13 mils. I fear the erector is not centered. Need to confirm this with optical bore sighter.
Click to expand...

You probably have your windage way off from center. What rings do you have? USO has windage adjustable rings so that you can maximize your erector travel in all directions
 
I will check on the rings. Also, I have a windage stop, forgot to mention that.
 
Circling back around to this...

Finally got the magnetic bore sight in the mail today. This still isn't making any sense.

I followed the videos step by step, first centering the erector. Next I bottomed the EREK knob to create a zero stop, then turned the center screw CCW until I felt tension.

Why am I 9 mils low??? The cross hairs are 9 mils above the center of the bore sight target, putting the bullet 9 mils low at 100 yards.

Is this typical? I am basically losing 9 mils or elevation.

Thanks ks in advance.

-BT
 
Circling back around to this...

Finally got the magnetic bore sight in the mail today. This still isn't making any sense.

I followed the videos step by step, first centering the erector. Next I bottomed the EREK knob to create a zero stop, then turned the center screw CCW until I felt tension.

Why am I 9 mils low??? The cross hairs are 9 mils above the center of the bore sight target, putting the bullet 9 mils low at 100 yards.

Is this typical? I am basically losing 9 mils or elevation.

Thanks in advance.

-BT
 
Got this stupid issue figured out...Barrett has 3 generations of the M98B.

First gen has a flat base.

2nd gen is a 20 MOA base.

3rd/current gen is a 30 MOA base.

I have a flat base....F me.
 
i hear what you are saying i was at the range and i went from 600 to 800 yards and ran out of elevation. the knob turned and clicked but the reticle stopped moving. but i did not zero the scope on this new rifle with the EREK> i just set it with the knob.

i have ordered a 20 MOA base and i am going to re zero it using the EREK. but no one could explain why my scope keep dialing and clicking but the reticle had stopped except i did not have it set up right. but when i backed it back down it tracked perfectly.
 
buffybuster said:
Or if you have windage dialed in to get your zero, you're loosing available elevation as the erector tube is over to one side.
Click to expand...

While this may have been true with older scope designs, I have not found one modern scope where the erector comes anywhere near contacting the main scope tube, and the limit of the erector travel describes a square. In other words, the elevation travel is identical with the windage centered or maxed out in either direction.
 
If your still having issues setting up the EREK knob give me a call and I can put you in touch with a technician that can walk you through it.

Becky @ U.S. Optics (714) 582-1956 Ext 203
 
I didnt realize how important knowing the specs of the scope base would and could effect the scope elevation , thank you geoff3
 
BenTerrible said:
I watched the video a few times. It says to bottom the erector screw by turning it CCW while holding the EREK knob. Then to bottom the knob all the way. I had this applied and had to come up lots to find zero.
Click to expand...

I had to come up a good 3 mils from bottom to zero too. Having said that it left me plenty of room for elevation.
 
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