POI Change with scope over time

bushwhacker

bushwhacker

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I decided to post this after reading post below about POI change with zoom change. My Tasco 3-9 variable, which I had on my rifle for a number of years, seemed to develop a glitch. I would sight it in on 9 power before moose season and when I next checked it out a year later, it would be off by maybe 3"@100Yd. I soon learned to only adjust it HALF as many clicks as should have been requried, and after chasing it back and forth a few times, would get it centred. I would keep track of my adjustments, and when I had it on, I would be just about where I started from. After having this experience a couple of times, I got fed up and changed to a Bushnell. It seems to hold its setting. I still have the scope sitting in my drawer, have resisted the temptation to advertise it on EE, because I don't want to stick someone with a bad scope, but wonder if anyone has had similar experiences.
 
bushwhacker said:
I decided to post this after reading post below about POI change with zoom change. My Tasco 3-9 variable, which I had on my rifle for a number of years, seemed to develop a glitch. I would sight it in on 9 power before moose season and when I next checked it out a year later, it would be off by maybe 3"@100Yd. I soon learned to only adjust it HALF as many clicks as should have been requried, and after chasing it back and forth a few times, would get it centred. I would keep track of my adjustments, and when I had it on, I would be just about where I started from. After having this experience a couple of times, I got fed up and changed to a Bushnell. It seems to hold its setting. I still have the scope sitting in my drawer, have resisted the temptation to advertise it on EE, because I don't want to stick someone with a bad scope, but wonder if anyone has had similar experiences.
Click to expand...

It would have done the same thing if you just fired 10-20 rounds through the rifle - the group would have wandered around until it settled back where it was orignally. Sounds more like a rifle glitch but it is a strange one.
 
Sound like you scope is at it's end of life. It might hold a zero in a rimfire, but it may be punch drunk now.
 
bushwhacker said:
I still have the scope sitting in my drawer, have resisted the temptation to advertise it on EE, because I don't want to stick someone with a bad scope
Click to expand...

Send it to bushnell for repair or throw it out.;)

Sometimes cheap scopes do funky things....
 
Bushwhacker,
What you are seeing is common. Guys will shoot their rifle and adjust sights until they have their zero set for a warmed up and dirty barrel. If it happens to be a heavy varmint rifle set up for gophers all is well. Next time they will come back with their cold barrel and wonder what happened to their zero. Maybe they scrubbed the bejesus out of the bore as well. The only thing that matters is that the first cold shot or 2 goes where its sent, but that point seems to get past some experienced shooters. Ideally a barrel will shoot to the same POI hot, cold, clean or dirty but don't bet on it.
A related problem is the shooter who finally gets his rifle dirty enough to shoot, then takes it home and cleans it.
 
The Bushnell Trophy seems to hold the zero OK. The Tasco did too, for a few years. I would have bought a better scope originally, but I finally got the widow to sell me the rifle a week before Moose season, and I just had time to buy the scope at the closest Crappy Tire and sight it in. It wasn't that the rifle wouldn't group, the group just wasn't in the right place. I usually fired 3 shots first, and then checked. I might use singles to get it back on line and then three to verify. The fact that if I should have had to turn 12 clicks to get it back and only 6 would sometimes be too much or close was probably an indication. Blargon said send it to Bushnell. Do they service Tasco? I would want an estimate first.
 
I saw a cross sectioned zoom scope once. It looked like a watch. A lot of small pins, cams and springs. A lot to go worong. This is why I prefer fixed power scopes for serious work.

The differences between cheap scopes ands expensive ones includes the repeatability of the cliks and the zero when zooming.

A zero that shifts with zoom is not unusual for a cheap scope. I have a real cheap zoom on a Ar-15 that got zeroed yeasra go. I have no intention of touching it in the future. Clicks and zoom don't matter on that rifle, so the cheap scope is ok.

You could have done the rough zero on 9 power then let the rifle cool and do a fine tune at 3X, where you hunt.

The comments about zroing warm rifles are valid. I have seen guys shoot 20 shots, zeroing a hunting rifle and leave the range with a big smile. Unless the rifle has been well bedded, the zero shifts with heat.
 
Yep. Had a Tasco, long ago, that would not hold zero. The horizontal would move when the bolt was opened and closed. Watched it through a bore sighter then changed to a Bushnell Scopechief.
If the scope is old and out of warrantee, it's likely not worth fixing.
Go here to find out if your scope is covered by Tasco's warrantee.
http://www.tasco.com/support.cfm
 
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