[5ptdeerhunter]

Shot my 870 on Saturday. I was sighting in my Bushnell Trophy 1.75-4x. I only had 8 slugs but figured I could get it close enough until I bought some more. I was shooting down a hill but I figured the range at about 100 yards. The first 3 shots hit in a small triangle about 7" high and 2.5" right. So I moved the adjustments 28 down and 10 left. (1 click = 1/4".) I looked through the scope and thought it was blurry. I had a friend check it for me to make sure it wasn't just my eyes. But I shot some more anyway. I fired 3 more shots. The 1st shot hit 13" low and 13" right. The 2nd hit 1/8" high and 1" left. The 3rd shot hit 1" low and 15" right. I got frustrated and just moved back the adjustments and fired one more it hit 6" high and 6" right. I gave the gun to my friend to try my last slug and he hit right near my first triangle. I hate sighting in guns. My friends aways get guns that are sighted in and I have to do all that work on mine.

But I want to know if anyone has had a problem with the focus of the scope changing after adjusting it? Or having there gun shoot that way? I had a good rest. I wasn't moving much at all. I was sitting down and had a sturdy bipod. I have had problems with incosistency before with this scope and gun combination, but the slugs I am using are custom loads and shoot great in my other guns and my friend's guns.

[Traveler]

If you have to refocus your scope after shooting or making any other corrections you have a poorly made scope. If you have had trouble using this type of scope before why do you still attempt to use one?

Spend a little more money and get a better set of optics.

[redneck2]

are moving around by themselves inside your scope

I had a Simmons 44 Mag scope on my muzzle loader. Bad case of "wandering zero". I finally got smart, trashed it, and got a B&L, after missing out on a 14 point buck (the deer was shot the next weekend by somebody else)

Lose that scope and get the best one you can afford, even if you don't think you can afford it. I had a fixed Bushnell 4X for several years on my 870 and it worked OK. I'd suggest something along the lines of a B&L, Leupold, or Burris. Adequate lower priced scopes are the Bushnell and I've heard the new Weavers are good.

Make SURE it says waterproof/fogproof...and get Butler Creek flip caps for both ends

A slug gun has a lot of recoil and beats a scope pretty hard.

edit...I didn't see that you already had a Bushnell. Guess it kinda proves the thing about lower priced scopes. If you look at a cut-away of a variable, they've gotta do a lot of things (change power, stay waterproof, stay zero'd).

I've been hunting for over 40 years. In scopes, you get what you pay for.

I'd stay away from Swift, BSA, Tasco, Simmons, etc. Also, if you have a good dealer that you do business with, they might take a scope off a trade in rifle. My local dealer is happy to do that as the rifle/scope combo usually doesn't bring much more than just the gun alone. HTH

[HSMITH]

The cheapest good scopes out there are the Leupold Vari-XII and higher, and the Nikon Monarch series. The fellas are right, it is bad optics that are causing you the grief. The added eye relief of the good glass will be a blessing too on a slug gun. Spend some money and it will get SOOO much easier.

[RussB]

I have had good luck with cheap scopes on shotguns, so I'm not going to say, "just buy another scope"

I will say, go out and buy slugs, lots of 'em.

A 100 yards is a bit optimistic for sighting in slugs...start at 50yds. Use a solid rest, and trigger control.

Next, I shoot a (minimum) 3 shot group before I make any adjustment to the scope. (just like you did)

Now, once you're all sighted in, clean the barrel, and fire a shot cold out of the gun. Repeat 2 more times. When you hunt, the barrel will be cold. You need to compare POI from a cold barrel to a hot one. Leading can mess things up, too.

Oh, and make sure the scope mounting stays tight. Re-check it while shooting.

[ojibweindian]

I know this is WAY late and $$$$$ short, but I'd like to say something for posterity.

It's quite possible that the ammo is to blame. If the gun doesn't like the ammo, the target will look a lot like you're paterning a shotgun. As an example, I have a Bushnell Banner 4-12x40 that I thought was screwed. I was literally getting 5+ inch groups at 100 yards with a load I put together. I backed off the charge a few grains and, behold, I now get groups between 0.60 and 0.75 inches at 100 yards. And the scope tracks well, too.

[Dave McCracken]

Let's start from Square One.

Make sure the scope is mounted properly.

Make sure the barrel isn't loose. I tighten the mag cap up as far as my hands will make it and then use padded channelocks or visegrips to take it ONE click tighter. Double check to ensure the barrel doesn't move.

Establish zero at 25 yards for starters and see how the groups, uh, group.

Try another two or three slugs(Good thing 5 packs are cheap) to see if the ammo isn't right for that 870. Those custom slugs may shoot great in your buddy's gun but be less accurate in yours. Once you find a slug your 870 "Likes", buy lots of the same lot.

If all that doesn't do the job, buy a new scope.

HTH...