Sighting in help please

MD DEERHUNTER · 09-19-2009, 03:31 AM

Couple weeks ago I went out to the range with my Thompson Center with Nikon Omega Scope. First I sighted in at 75-yards, took 2-shots and hit dead center on the target. Moved the target back to 100-yards and couldn't find the target. Moved it back to 75-yards and couldn't find the target. Moved it back to 40-yards and was at the bottom of the target. So after each shot I made scope adjustments til I couldn't adjust it anymore. But I was still shooting like 3 inches low. Where did I go wrong? Did I over adjust at 100 yards? This past week I got my scope boresighted again and going out to the range again today. Any suggestions? Thanks for your help. I'm shooting 250 grain Thompson Center Super Glide with 100 grains of 777 pellets.

HEAD0001 · 09-19-2009, 07:40 AM

Here is a simple way to do it. It takes a good bit of time to do this. But you will will not have to start over.

Shoot your rifle at 25 yards. At 25 yards never adjust your scope more than 8 clicks at a time. Clean the bore and reload. Then repeat until you are dead on. Then back out to 50 or 75 yards and repeat-with one difference. Never adjust your scope more than 4 clicks at extended distance.

Scopes like the Nikon Omega are not known as good tracking scopes. And you do not want to keep changing the scope back and forth. You want your tracking to go in a single direction until you get it where you want it. And the distance moved by 4 clikcks on one Omega is not exactly the same as the next one.

Go slow and keep the barrel clean. When you get it real close at your final distance then make sure your barrel is very clean between shots.

This will get you there. It takes patience. But if you want it done right then be patient. Tom.

MD DEERHUNTER · 09-20-2009, 01:58 AM

Thanks Tom. Sighted in @40 yards, it was off the paper to the left about an inch. Got in adjusted 1-inch high and then I moved my target back to 65-yards and got a nice group and I'm happy with it. Got my gun cleaned, put away for hunting season. Muzzleloader season opens October 22nd here in Maryland.

spaniel · 09-20-2009, 04:53 AM

Which T/C gun?

Part of the problem with some of them is the barrel configuration under the scope mount combined with the location of the screw holes. The scope does not mount in line with the bore and you end up with shooting low (like you experienced) and either running the scope all the way up (like you did) or totally running out of adjustment.

My easy and cheap solution was to cut the side of a soda can into shims, drill holes in them, and put like 3 layers under the rear of the scope base. Using a curved surface of the can you can cut shims that conform nicely to the barrel. Now my scope zeroes in the bottom range of travel rather than the upper end.

lemoyne · 09-20-2009, 06:54 AM

It sounds to me like you have a problem that does not relate to normal sighting in.
The scope is not parallel to the bore. Loose mount, mismatched mounts, something under one end off the mounts, or mismatched rings could cause this so could a loose ring [either bottom or top]. A bent scope barrel or a really bad scope. I would take off the scope and try the open sights if the sight in reasonably well then take off your mounts and make sure you have the right ones for the gun before you put them back on check the rings and make sure that they have exactly the same thickness base clean everything ,a metal shaving or a piece of paper in the wrong place can cause a lot of grief. Lee

LaneNebraska · 09-20-2009, 07:33 AM

Quote:

Originally Posted by lemoyne

It sounds to me like you have a problem that does not relate to normal sighting in.
The scope is not parallel to the bore. Loose mount, mismatched mounts, something under one end off the mounts, or mismatched rings could cause this so could a loose ring [either bottom or top]. A bent scope barrel or a really bad scope. I would take off the scope and try the open sights if the sight in reasonably well then take off your mounts and make sure you have the right ones for the gun before you put them back on check the rings and make sure that they have exactly the same thickness base clen everything ,a metal shaving or a piece of paper in the wrong place can cause a lot of grief. Lee

What Lee said +1 !