View Full Version : scope tester

03-13-2010, 05:25 PM
I made up a neat tool today that may be as old as the hills or a new idea. I get a lot of weird groups that point toward something possibly loose or moving inside the scope. Three shots in a very tight group and two in another tight group. Or four and one. I took a 1"x5"x6" block of alum (probably should have used steel) and machined the top to leave two long bases. It could have just been a flat surface drilled and tapped for bases. I mounted two scopes side by side almost touching each other. Both 36x's. One weaver and a sightron. Now by zeroing one in on an exact spot and then slowly looking through the other scope and carefully moving the crosshairs to the same spot, I plan on jarring this whole rig somewhat and seeing if the crosshairs of both remain fixed. With a varible power, you could power down, check, then back up and check. Of course if there is a change, you wouldn't know which scope it was, but in time I hope to find a pair that never drift to use to test other suspect scopes. I just finished it,so no real data yet, but I've got quite a few things I want to resolve.

Gene Beggs
03-13-2010, 06:46 PM
Charlie Hood made and sold what he called the Hood Scope Checker. I bought one and it worked so well I bought another one. With the Hood Scope Checker you slide the checker on your rifle's scope rail and tighten it in place and then you place a scope of known repeatability on one upper rail and the suspect scope on the other. You dial the scopes until they are centered on the same spot on a target and you fire a round. You zero the two scopes to POI and fire another round or three. The crosshairs of both scopes should still be on your group. If they are not, one scope is bad.

Francis, you are so right about the Hood scope checker. I keep a frozen Leupold 36 in a Bukys mount permanently installed on mine. I was sorry to hear that Hood is no longer making them. Without such a device, one is just guessing about the reliability of his scope.

In his book, "Extreme Rifle Accuracy" Mike Ratigan goes into great detail about checking scopes. He says his scope checker was made by Daryl Loker and I sure like the design. I wish it was available commercially.

03-13-2010, 07:32 PM
In Ratigan's book he also states....

That a "new" scope is just that... fresh out of a new box, and could quite possibly be a bad scope or a good scope... new does not mean good.

Also a "good" scope could be new or old and that although it is good it could be about to be a "bad" scope.

but once a scope is determined to be bad. It will remain bad or questionably bad until something is changed to the point that it tests good, at which point it could be about to be bad...

And that the only time you know that a scope is good or bad is during the testing... and after the test a good scope could become a bad scope...

take it for whatit's worth. The hood scope checker lets us take the guesswork out of a suspect scope so we know what to send back to Alan Tucker...


03-13-2010, 07:48 PM
Francis, you are so right about the Hood scope checker. I keep a frozen Leupold 36 in a Bukys mount permanently installed on mine. I was sorry to hear that Hood is no longer making them. Without such a device, one is just guessing about the reliability of his scope. I wish it was available commercially.

Now there is something for your next project. An item you can market to the rest of us. Go for it! :) Art

03-14-2010, 07:50 AM
This method that Hood used sounds pretty good. His double scope gun mount would do everything mine does and also simulate real world recoil and general gun handling issues. Sounds basically like a heavy duty set of rings with bases built into them for the upper set. I'm thinking that if this was done a long time ago, that scopes didn't have the large MM front bells that are common today, making the whole arangement uncomfortably high.

03-14-2010, 09:54 AM
Thanks guys, the pictures you posted look almost exactly like the mounting block I made except mine doesn't mount on a gun, but sits on a rest with three adjustment screws for leveling/pointing. I'll post later the info that I get about three weaver t36's, two sightron 36's, a redfield 6-18x, a nikon 8-32 and a tasco 10-40. (yes tasco---don't look at me that way!)

Bob Kingsbury
03-14-2010, 10:04 AM
Using a frozen scope without the adjustable mounts in one side
of the scope checker. It would be clear which had a problem

03-14-2010, 01:32 PM
I would certainly think that quite quickly I will find two scopes that no matter how much jarring, will show no deviation to each other. Both of these will be 'certified' (in my opinion anyways) to check other scopes against.
BTW, the nice people in china that made my 10-40 tasco, were considerate enough to put all the brand logos and made in china, on the bottom close to the barrel, as to be very hard to read when mounted.

03-14-2010, 11:21 PM
at the Shamrock or ship after the match.

"Snuffy" Smith howsmit@bellsouth.net

03-15-2010, 01:41 AM
Another view and I think you'll agree Charlie knows his stuff. I should add that you can mount the scope checker to the right or to the left depending on your port configuration. You may also find it is necessary to turn one scope 90 degrees in the rings so the turrets don't clash. When you do this elevation becomes windage and vice versa. Also take the turret caps off before you mount the scopes. I will say I've used this checker a number of times for my own scopes and Paul's as well as David Apple's and for guys who just knew it wasn't their fault they were throwing shots.
I looked at the picture again and that is David Apple's scope on the checker in this picture.

Francis, you seem to have checked a good number scopes, how many have found to be bad and what type of fixes did the mfg. complete?.........Don

jackie schmidt
03-15-2010, 07:30 AM
In order for a scope checker to work, you have to have 100 percent confidence that the testing scope is 100 percent reliable.

As for how Companies handle scopes that are sent back, I would say that many simply send you a new scope. That was Weavers policy for a while. I know how difficult it is to get one apart, if man hours is any consideration at all, that is probably the most cost effective route.

I can tell you this. I was sure I had a problem with one of my March Scopes. I sent it back. They took pictures of the entire scope dissassembled, (close-up of scopes serial number on the tube), and the procedures they went through to check it. They said they found nothing wrong, but double checked everything.

I put the scope on my 30BR HV, and it is working fine. The Rifle is shooting great.

I sold my other 50x Marches, and just bought a new 40x. I got tired of looking through that glass on the 50's, the 40 is much better.......jackie