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Old March 5, 2013, 03:49 PM   #1
JayClark79
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End of scope adjustment range?

Hey gang I just got back from the range and I was sighting in the scope on my Mossberg 715t... My scope seems to be at the end of its elevation adjustment (all the way up) and im shooting still low.. Its right on the 3rd mildot... Left to right Windage is right now.

Is my scope sitting to high off the barrel? Is there anything I can do? Id rather not be stuck at the 3 down mildot lol

The shots were at 75 feet
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Old March 5, 2013, 06:17 PM   #2
sc928porsche
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Sounds as though you will have to shim the back of the scope. I always try to shim at the scope mount, but sometimes it cant be done. Shims can be made from a soda can and a pair of sissors. You will want to take the mounts off the rifle and lay some shims between the rifle and the mounts (in your case the back) then reinstall the mounts. If you have been sighting at 100 yds, try 3 shims to start. You can add or remove to get you back on. Be sure to recenter your scope adjustments first.
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Old March 5, 2013, 06:33 PM   #3
RonR6
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Are you sure you moved your scope adjustment in the correct direction. If its a bolt action pull the bolt and sight down the bore with the rifle on a rest and adjust in only direction you have left, see if it gets closer to center. Just a thought to help out. I helped a friend adjust his scope at our range and he had that problem, turned the adj knob the wrong way.
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Old March 5, 2013, 07:00 PM   #4
mapsjanhere
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Ok, first, you're shooting at 75 feet. You don't sight your scope at 75 feet, especially not with a rifle where the scope sits a couple of inches above the barrel. That said, you still are doing something wrong there. 3 mildots are about 10 MOA, or 2.5 inches at 25 yards. If your scope is 2.5 inches above the barrel you're scope line is parallel to the bore. It should be that with the reticle centered. As most scopes have at least 25 MOA travel you should bottom it out, especially not low, because if you're shooting low at 25 you will be shooting low everywhere.
My first suggestion is, take the scope off and remount. Just to make sure you didn't tighten something wrong. Then remount again, but with the rings switched. If the rings are uneven, you just made yourself a great long distance rig as your now have a huge adjustment range . If that doesn't help, try a different scope. If that can't sight either, the rail on your gun is bad.
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Old March 5, 2013, 07:17 PM   #5
JayClark79
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Well i originally sighted at 50 feet and I had it set in pretty good but it was definently at the max elevation at that point.. I went to tighten the screws down and screwed it all up... So today i started at 75 feet just because the scope has a setting for 25 yards.. there is no setting for 50 feet.. the settings go 3 yards, 5 yards, 25 yards, 50 yards, 100 yards, infinity

Even at 15 feet/5 yards it was still way low..

I havent measured but I will later, the scope is sitting on top of the carry handle on the gun so it may be higher then 2.5 inches.

I can get scope rings that are 5mm shorter... would that make much of a difference if the scope is after all higher then 2.5 inches?
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Old March 5, 2013, 07:28 PM   #6
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Is shimming a common thing? I was thinking the line of sight at that point wouldnt be parallel which would cause trouble when changing distances?
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Old March 5, 2013, 07:34 PM   #7
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Bad scope.
Bad mount or mounted incorrectly.
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Old March 5, 2013, 08:20 PM   #8
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A scope on a carry handle is going to be 4" or so over the bore.
What kind of scope and mount are you using?
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Old March 6, 2013, 04:17 AM   #9
JayClark79
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Its a UTG bug buster with the medium profile mounts
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Old March 6, 2013, 01:01 PM   #10
SSA
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As suggested above
Quote:
take the scope off and remount. Just to make sure you didn't tighten something wrong. Then remount again, but with the rings switched.
Get the adjustments in the scope centered.
Try to get it sighted in at 50 or 75 yards. It's going to hit low at closer ranges. Nothing you can do about that.
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Old March 6, 2013, 01:33 PM   #11
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Quote:
A scope on a carry handle is going to be 4" or so over the bore.
Quote:
Try to get it sighted in at 50 or 75 yards. It's going to hit low at closer ranges. Nothing you can do about that.
I just noticed what he was trying to do and am in full agreement. It would take a miracle if he was able to get that set-up zero'd at 25 yards.

Using some basic information I calculated a 2" MPBR (maximum point blank range).

- approx. 2/3" low at 25 yards
- first zero approx. 32 yards
- second zero approx. 82 yards
- 2" MPBR approx. 92 yards.

Still doesn't get him down to the 3rd mildot so I'd recheck everything and swap the rings around.
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Old March 6, 2013, 05:44 PM   #12
JayClark79
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So you guys are saying that because of the scope being so far above the barrel it would be impossible to get sighted in a such a short distance?.. I can see that making sense.. Ill have to find an our door range around my area.
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Old March 6, 2013, 06:48 PM   #13
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Not impossible.

If you have a scope with enough adjustment, or an angled mount, or if you shim enough under the rear of the scope, you can sight it in at 25 yards. Then, you'll be 4" or something high at 50 or 75 yards. And you'll still be low at 15 yards.

If everything you have now is correct and straight, you should be able to sight in at some distance. 50 or 75 yards might be easier to achieve than 25.
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Old March 6, 2013, 06:55 PM   #14
mapsjanhere
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I'm still surprised, according to the description he's got a close combat sight, those should adjust to any zero. Unless of course it's supposed to be zeroed at 100 and the dots are the close distance aim points.
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Old March 8, 2013, 09:15 AM   #15
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4" above the barrel would need 4 minutes "up" at 100...
and 16 minutes at 25 yards- meaning a total adjustment range on the scope of only 32 minutes...which just about every scope made would have.

And he says he's "way low" still. The math doesn't add up.

One of the more useful "tools" I have is the Leupold boresighter. Not only is it generally fairly accurate- at least enough to get on paper- it provides a visual reference point on a graph within the viewfinder so that you can change scopes and "zero" to the same reference point- and it would show if there were a difference if re-mounted.

I wouldn't waste another trip (range fees) solely to test this again- I would borrow a scope if possible to swap out if you don't have another, or just return it to place of purchase for exchange. IMO, the odds point to defective scope above other possibilities.
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Old March 8, 2013, 10:09 PM   #16
reynolds357
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Nothing is wrong with zeroing at 25yds. In most rifles, a 25 yd Zero is very close to a 200 yard zero. I usually zero at 25. Only take 2 shots that way. Then move to 200 or 300 for load development etc. etc.
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Old March 9, 2013, 12:32 AM   #17
Metal god
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Quote:
the settings go 3 yards, 5 yards, 25 yards, 50 yards, 100 yards, infinity
I don't understand this quote ^^ Are those numbers for the yardage the scope should be sighted in at when dialed to them ? Meaning if you have it set on 50yds it should be zeroed at 50yds ?

Those numbers sound like the parelax adjustments to me . Are you using the top turret on the top center of your scope ?
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