View Full Version : Mossberg 100 ATR won't zero

November 14, 2011, 12:54 AM
Hey all,

I recently purchased a mossberg 100 ATR chambered in 30.06 springfield, took it to the range, and couldn't get the darn thing to shoot straight. I tried using both federal and winchester 165 and 180 grain ammo, I boresighted it properly, and still I couldn't get it to hit the paper at 50 yds. One of the older gentlemen at the range offered to help me and he couldn't figure it out either. He did say that my form looked fine, and we inspected the muzzle crown which also looks fine. We cleaned the barrel, tried using different ammo, but to no avail. It was as if the gun had a mind of its own - it would occasionally hit the paper, but in a completely unpredictable pattern.

Frustrated, I left it at the range to have the professionals take a look and see whether they could get it sighted in at 2 inches high at 100 yds. They didn't seem to have any luck either. A few days later I returned and asked the lady at the front about what was wrong with the gun and she didn't really give me anything too specific. On the charge receipt it said "could be the scope."

The scope adjusts for windage and elevation move in the proper planes (no diagonal movement or anything like that), and I made sure the scope mount screws were tightened properly (snug, but not overtight). I just don't see how it could be the scope, although I hope thats all it is. What do you guys think? Is there a chance that it is something more expensive, like a warped or improperly machined barrel?

November 14, 2011, 01:18 AM
it is easy to have a screwy scope where the cross hairs will physically move inside the tube. Ive had it happen on my BSA and Burris scopes. I changed them all to leupolds, trijicons, and EOtechs.

It IS possible that you screwed the scope rings on too tight where you permanently damaged the scope tube, unknowingly. unlikely, but possible.

Your gun is only as good as your optic. You should spend just as much on the rifle as you do the scope.

I hear Vortex is a great up and coming company. Their binos are fantastic.

I HIGHLY doubt it is the rifle.

good luck and re-post the results.

November 14, 2011, 05:39 AM
Until you get holes in paper it is impossible to figure out what to do next. If you have to shoot at 25 yards or use a huge piece of paper for a target do so. Your gun and scope could be shooting 1/2" groups, but you could be 3' off in any direction.

November 14, 2011, 10:44 AM
Did you mount the scope yourself? The reason I ask is that about half the time when I mount a scope myself I get it wrong for no apparent reason and I wind up having to take it to a shop to have someone else remount it and boresight it.

Someone higher in the thread suggested firing it at 25yds to start. I'd go one better than that and start at a ridiculously short distance like 10yds (and use a BIG target). Then back out from there in 10yd increments. With an issue like you describe this may be the only way to find your point of impact. This probably will require shooting it in the outback as I don't know any ranges with 10yd increments starting at 10yds.

Your post caught my eye because I just sighted in my own 100ATR on Saturday. I had the scope mounted and boresighted by my local shop (a cheap $60 Tasco scope). At 100 yds my first shot just barely hit the edge of the target. 10in high and 2 in left of center. I didn't have any trouble adjusting from there. But if that shot had been an inch higher I'd have been searching for a few shots. The range I was at had only 100yd lanes open.

Good luck

November 14, 2011, 11:16 AM
Move to 25 yards, see how it groups (if it will even do that). My money is the scope is causing your problems.

November 14, 2011, 11:27 AM
The scope is broke.

November 14, 2011, 03:22 PM
Your gun is only as good as your optic. You should spend just as much on the rifle as you do the scope

This seems a little excessive to me in this situation. Yes, if I'm spending lots of money on a rifle. Not so much if I'm putting together a bargain rifle. The 100ATR can be had for as little as $250 in 30-06. More commonly it runs in the 300-350 range. 3-9x40mm should do the trick for a scope. A quick search of cheaperthandirt.com reveals that the most expensive 3-9x40mm runs $600 (Leupold). The least expensive is a Tasco Pronghorn at $32. There are plenty available in the $300 range, but these are way more scope than that rifle needs. I would think that for a $300 rifle, a $100 scope would be a good match. Anything more is like pimping out a Hyundai to me. I don't think the benefits of the better $300 scope justify the extra $200 spent.

On the other hand, putting a bargain scope on a nice rifle is like putting cheap tires on a Corvette. Buy the Gatorbacks. You have a Corvette for christs sake.

November 14, 2011, 04:39 PM
You don't have to spend as much or more on the scope than the gun. But in this case it would be a good idea. I've found very few scopes under $200 that were worth bringing home. On the other hand I've seen $200 rifles that would shoot as good as $2,000 rifles.

At right around $200 the Nikons and Burris are good scopes. The only sub-$200 scope I'd have is the $160 Redfield.

Once you get over $400 I cannot see enough difference to justify the expense. If I were buying a scope it would be something between $200 and $400 whether the rifle cost $200 or $2,000.

In this case it "COULD" be the scope. But until you get it on paper at some range there is simply no way to know. Get a bigger sheet of paper to shoot at or get a lot closer until you are hitting something. Then you will know in which direction and how far to make adjustments.

If you are getting decent groups and the scope adjusts then you will know the scope is OK. If you are shooting all over the place it is either the scope or mounts. If you move the adjustment dials and the POI does not change as it should then you have a bad scope.

November 14, 2011, 11:43 PM
It could be a bad scope, loose rings (stripped threads?), loose base or bases or the barrel and action are not properly secured to the stock. Are there any marks on the scope tube to indicate the scope has moved in the rings during recoil?

January 12, 2012, 11:02 PM
I purchased a Mossberg ATR 100 combo in a .270 and have the same issues. I have replaced the scope thinking thats what it was but it seem to send the shot where ever it feels like at the time. Sometimes it will hit the paper some times high right, then low right, than off to the left.. Did not make any sense. I got tired of it and finally emailed Mossberg. They asked me to send the gun to them and let them check it. Sent it in two days ago I will let you know how the results turn out.

January 13, 2012, 11:51 AM
i have done the same thing to a tasco scope on a marlin model 60 i was new into shooting and figured at that time if it was a 1inch scope ring then it was ment to be cranked completly shut. but yes that made the scope act all kinds of stupid. trial and error i guess

January 14, 2012, 10:35 AM
could be it doesn't like the winchester stuff.:(

January 14, 2012, 10:48 AM
As several others have suggested, I would start my moving close enough to the target to get holes in the paper. If the groups are spraying or point of impact does not move when the scope is adjusted, I would start by installing a different scope to see if the problem is solved or if it continues to do the same thing. If the problems continues with the second scope the problem is with the rifle or scope mounting hardware. I would start with the obvious such as checking the mounting in the stock, checking the bolt head etc. Beyond that a good gunsmith or back to the factory would seem to be the next step.

January 14, 2012, 11:02 AM
I have a 100atr in 243. It is not an inherently accurate rifle, but for the price I did not expect it to be. I originally purchased if for a ranch truck gun so I would not be beating up my good rifles. It served well in that capacity. It was capable of 2 to 3 inch groups at 100 yds with most factory ammo.

I have since done some work to smooth and lighten the trigger (pre accutrigger model from the lawyer proofing era) and installed it in a Boyd's laminate stock.

I now have hand loads that it will consistently shoot 1" or a little better at 100yds

January 14, 2012, 05:49 PM
First thing I would do- if you suspect the scope is giving you issues, *remove* it. Shoot it with irons (or naked if none present). If it is the scope, you'll probably shoot better at fifty with no sights than what you're currently getting.

From there, continue troubleshooting. Literally. :)