Rifle Scopes Adjusting USO EREK knob - get the 20moa out?

[valise]

So I picked up a second hand USO 1.8-10x.

I read the instructions, watched the video a couple of times, searched the threads here, watched the video again and took the scope out to the range.

I don't have a bore sighter so I set up 25y and get on paper, move it out to 100y and I'm shooting 4 inches high.

Come back, read the instructions, watch the video, search the threads and go back out.

I can't make the reticle go low enough to get it bore sighted at 100 yards. I notice the video says they ship with a 20moa pitch.

Can I 'adjust' the pitch back to 0 MOA? Or send it to USO?

 

[NoExpert]

Re: Adjusting USO EREK knob - get the 20moa out?

If you're shooting 4" high wouldn't the reticle be too low already? May need to turn the erector screw the other way.

Also start out with getting the reticle mechanically zeroed by laying the scope in the rings and rotating it side to side while adjusting the elevation and windage knobs till the reticle stays centered in the scope. This should help out a lot, then play with the erector screw if you can't get it centered with the elevation knob alone.

 

[valise]

Re: Adjusting USO EREK knob - get the 20moa out?

Saturday I simply sighted in using 3 shot group and reticle adjustment at 25 yards and shot some nice groups (it's on my 77/17 hm2 at the moment - go ahead and LOL now). When I went to check the 100 yard, it was 4 inches high.

So I re-read everything. I set about mechanically zeroing by barrel sighting at 25 yards, then rotating the scope - think I got it close enough - then went about EREK adjustment.

The EREK Allen screw is rotated C.Clockwise till resistance met, then rotate knob down, back off 6-8 clicks (this puts it about Zero line), then rotate Allen screw clockwise to bring reticle into match. Problem is at this last point the reticle only goes UP and I want it to come down more...?

I'll re-review John's link, but think I had it correctly noted.

 

[Brain]

Re: Adjusting USO EREK knob - get the 20moa out?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: valise</div><div class="ubbcode-body"> When I went to check the 100 yard, it was 4 inches <span style="font-weight: bold">high</span>.

Problem is at this last point the reticle only goes <span style="font-weight: bold">UP</span> and I want it to come down more...? </div></div>

Your issue isn't one of figuring out an EREK knob, but rather what the basic principles of scopes are.

If you want POA to match POI, which direction do you think the reticle needs to go if POI is 4" high?

 

[Aries64]

Re: Adjusting USO EREK knob - get the 20moa out?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Brain</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: valise</div><div class="ubbcode-body"> When I went to check the 100 yard, it was 4 inches <span style="font-weight: bold">high</span>.

Problem is at this last point the reticle only goes <span style="font-weight: bold">UP</span> and I want it to come down more...? </div></div>

Your issue isn't one of figuring out an EREK knob, but rather what the basic principles of scopes are.

If you want POA to match POI, which direction do you think the reticle needs to go if POI is 4" high? </div></div>
Ah, the harsh light of reality...


Keith

 

[valise]

Re: Adjusting USO EREK knob - get the 20moa out?

I'm willing to have my 'doh' moment when this is all done but let me restate this without the 4'' high reference and hopefully see this harsh light.

Without shooting at all, I do not seem to be able get the reticle LOW enough to match physical bore sight under 100 yards (haven't tried further out).

I can shoot a group and move the reticle to match, POA = POI. Basic principles in tact.

However moving target distance out, new group was high relative to expected bullet trajectory at 100 yards, which shouldn't be more than an deviation inch in my case.

USO website - scope mounting video 35 seconds into it - "you're USO scope comes preset with a 100 yard zero on a 20 MOA down base"

I am running 0 MOA base, thus I can't get the bore sight + POA + POI to run even.

Back to my original question - can the 20 MOA down slope of the scope be adjusted out??? Apparently not as I've reached the limit down using the EREK adjustments and the reticle only adjusts upwards while still being too high relative too bore.

 

[Redmanss]

Re: Adjusting USO EREK knob - get the 20moa out?

You're still not getting it. Your shots are impacting higher than your point of aim. Your reticle will not move any lower, but at the same time it doesn't have to. It needs to move up.

Aim in on the target again. Shoot a group. While aiming at your original point of aim and holding the rifle perfectly steady, adjust your elevation <span style="font-weight: bold">UP</span> until the reticle is on your group. Shoot another group. POA/POI should be pretty darn close to each other. Congratulations, you're now zeroed, give yourself a face palm....

Don't let the "built in 20 moa" thing get stuck in your head, and remember the bullet doesn't lie.

 

[NoExpert]

Re: Adjusting USO EREK knob - get the 20moa out?

Okay, so if you're bore sighted on a dot 100 yards away, is the reticle aimed under or over the dot? If under you need to go up (CCW), if over you need to go down (CW).

 

[valise]

Re: Adjusting USO EREK knob - get the 20moa out?

At the 1 hash I can match up bore sight and reticle, room to travel in both directions.

At the 0 hash (bottom of travel for the knob) the reticle is 27moa high with full resist CCW to the Allan screw, not allowing the reticle to lower.

To get here it Jason at USO suggested [thanks - V]...
"Move your knob all the way up counterclockwise until it stops. Now do the same with your center screw. look where your reticle is. [This part isn't mentioned in the video link - V]

Now looking through the scope slowly move the center screw clockwise while holding the knob until you see the reticle move. As soon as it starts moving stop. [New clue - V]

Now dial your knob down "clockwise" Do this slowly and after every couple of clicks stop, look through your bore and make sure your rifle didn't move. Once your knob is bottomed out back it off 5 clicks counter clockwise. Now see where your reticle is. If it's centered on the target where your bore is, your done. If it's not move the center screw until it is. this will get you as close to "0" downbase with a zero stop as possible."


As soon as the wind dies down I'll get back out and try groups again.

So when you set the ZERO on your EREK knob, did you put it at the zero or one hash?

 

[NoExpert]

Re: Adjusting USO EREK knob - get the 20moa out?

I set mine at the zero with 10 clicks (1 MIL) available before it bottomed out. This gave me some "just in case" room for different ammo and atmospheres plus the full 9 MILs on the knob. I plan to do this on the new USO I'm getting as well.