View Full Version : Warped Scope???
July 11, 2009, 11:42 AM
I have a Simmons Wide Angle 44Mag scope on my Marlin 883 .22WMR. I took it out yesterday to varify Zero at 150 yards. I could not get on the paper! I moved down to 75 yards and tried again with the same results. I used the Iron sights to get on target, then looked through the scope. The center of the scope looked to be off around 4 feet to the left of the target at 75 yards.
I came back home and removed the scope and mounts, the mounts look fine so I mounted them back to the rifle and just set the scope down into the mounts (without the top of the rings installed). I placed my sand bags on my workbench and picked a spot on the wall to use as a reference point. I put some tape on the wall and drew a dime sized circle with cross hairs. when I align the bore of the rifle with the circl and look threw the scope it's off what looks to be about an 1-2 inches at an estimated distance of 10 feet. I rotate the scope 90 degrees (Top turett being 0 degrees) and the windage comes to center of the circle same with 180 degrees. At 270 degrees the circle begins to rool away from the cross hair.
Now that all of that is out of the way, Is there anything I can do to fix this problem besides buying a new scope?
July 11, 2009, 12:16 PM
Luckily it's just a Simmons (cheap $). Unfortunately, it's a Simmons (poor warranty). Buy a better scope. You could send it to the factory and pay $30 for shipping and handling, or take that $30 and add it to the price of the scope and get one that is much better.
July 11, 2009, 03:18 PM
If I thought the scope was warped, I would run a dial caliper on both ends and the tube with the scope in 'V' blocks or setting on the bottom half of the rings, if I wanted to center the cross hairs I would use the same set up, if the cross hairs scribed a circle around a point I would know the cross hairs are not centered, not a problem, it is recommended the scope point of aim be centerd with the point of impact.
July 11, 2009, 06:06 PM
What you are describing is a difference of about 60 minutes of arc off center for a 2" error at 10' and 30 minutes of arc for 1" error at 10'. According to Simmons (http://simmonsoptics.com/) the scope has 60 minute adjustment range, so the latter could be accounted for by the scope being at one of its adjustment extremes. If adjusting didn't bring it in, you either have a damaged scope or your rings don't line up with the barrel. Those are really the only two options that I can see?
Set up to bore sight on the wall target again with the scope out of the rings. Then get back as far as you can and look through the rings themselves. They should be looking at a spot above the target by the height of the ring centers from the bore center; usually around an inch an a half. They should not be looking either side of center.
You can make a scope spinner out of wood and round head nylon bolts from Lowe's or some other such place. You set the scope on it and turn it, adjusting the elevation and windage until the crosshairs stay centered while you turn it. I always do that before mounting a scope, so I know I am starting at the ring zero.
July 12, 2009, 10:44 PM
awbrock, from the celing hang a strang (string) and all the weight it will support, the string is a straight up and down (plumb) line instead of the target on the wall, then do everything you did before, except align the vertical cross hair with the string then adjust the cross hair to the far right then stop, you can count the clicks back to the left extreme or align the cross hair with the string then adjust the cross hair to the left (without moving the scope) then hang another string that aligns with the left extreme adjustment, half way between the two plumb lines is center, or you could count the clicks, from right or left half the clicks is center.
Elevation, vertical cross hair, iso-iso, rotate the scope 90 degree and do the same repeat the procedure.
July 14, 2009, 03:23 PM
Awbrock, from your original post, it sounds like you are saying the scope worked OK before but when you were trying to verify that it was still zeroed it was way off.
If that's the case, something probably broke loose inside the scope.
If on the other hand, it was never sighted in previously, the other posts gave good advice on how to proceed.
July 20, 2009, 01:09 AM
Thanks for all of the help guys.
The scope performed well before, I could consistantly hit a 1" circle at 200 yards. I even won a steak dinner from one of my friends after hitting a 1" metal fence post at 238 yards 3 out of 3 times.
I removed the rings and checked everything out, I made a ring alignment tool simular to the ones Wheeler makes. The rings were part of my problem. I used the Weaver rings "clamp type" the ones that pinch the recessed cuts on top of the reciever. They were out of alignment and well not very rigid. I have been playing with the idea of making a jig and drilling and tapping the reciever to mount a good set of rigid bases and rings, but I'm a little strapped for cash and time is a bit of a commodity.
I'm in the process of making one of those nifty blocks with the nylon bolts (great idea). Thanks!
I have mounted the scope using my original equipment (but with better alignment I used the string hanging from the ceiling and recentered the cross hairs) I just haven't had time to take it out yet and punch any holes!
Thanks again for all of the help!
July 20, 2009, 07:57 AM
What you describe is exactly what once happened with a friend's Marlin 783 (?) .22 Mag boltgun.
It turned out that the receiver grooves were not milled parallel to the barrel/bore.
The easiest cure would have been to D/T the receiver for scope base(s) - which he didn't want to pay for.
If it was a new rifle, he would have sent it back to Marlin under warranty, but since he bought it at least third hand, he just used it with the irons for awhile before sending it on down the road.
I found the problen via laying a long straightedge along each receiver groove, in turn, w/o the scope mounted.
When placed on one side, the forward end almost hit the barrel, while on the other side it pointed a few inches away from the muzzle.
July 20, 2009, 10:42 AM
After you get the crosshairs re-centered, a better mounting system and it's bore sighted (if possible), try this scope sighting technique:
Mount the rifle solidly with a mount and/or sandbags, etc. Put the crosshairs on the bullseye and fire one shot. Use a bright marker, bright tape, etc. to mark the impact point. Then remount the rifle solidly with the cross hairs centered on the bullseye. Important: The rifle must not move!
Now, with the rifle solidly set in place and the crosshairs on the bullseye, look thru the scope and without moving the rifle, move the crosshairs onto the impact point.
If you were able to move the crosshairs without moving the rifle, the bullet will hit under the crosshairs for whatever range you just sighted it for. I've used this technique for all kinds of rifles in all kinds of calibers. For those types that can not be bore sighted first, I'll do it one time at close ranges and then move the target to the normal range. Normally, the rifle is perfectly sighted with just one shot (Assuming good scope & mounts, etc) Hope this helps. Keep yer powder dry, Mac.
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