Rifle shifting zero, Please help

**umshiniwam** · 24-03-2010, 14:37

Hi

I was hunting with a friend this past weekend and he used my BSA .30-06 to hunt blesbuck.
We checked the rifles zero on Wednesday at Sahara, before embarking on Saturday morning.
On the farm, I again checked the rifle at the farm's range. When sighted infor my friend, the rifle shoots about an inch left at 100 metres. As my mate was arriving later on Saturday afternnon, I fired two shots andthey were left but touching each otehr so the zero was perfect.
Saturday afternoon he used my .30-06 to shoot a ram at 100m and another at 196m, both heart/lung shots.
The next day another ram was headshot at 120m. the headshot was low but that is why I do not like head shots. No apparent problem with the rifle.
That afternoon he completely missed a ram at 140m aiming at the vitasl area from a standing position over shooting sticks, at 140m. He is a good shot so we were all suprised at this.
On day three things went wrong. Aiming at the heart of a ram at 120m, the shot went through the hindquarter and fortunately broke the animals hips.
This, combined with the previous day's miss lead us all to believe that the cope had lost its zero. I recall that the muzzle of the rifle hit the Land Cruiser's roll bar quite hard when we went through a ditch the previous day. At the time I did not thing that it was hard enough to cause the scope to shift zero.

The farmer's assistant took him to the range to check the rifle and I continued to hunt. He fired two rounds at 50m and the first one was about about five inches low and two inches right.
The second shot was also about five inches low but now four inches to the right The third shot at 50m was the right height but still left. He fired two shots at 100m and one was not on the paper and the other was a couple of inches right.

I plan to take the rifle to a range again sometime and test it further. It seems that the rifle is shifting zero each time that it fires, which leads me to believe that the scope may be faulty.
It is a Bushnell Banner 3-9x40 and is barely three years old. I have checked the bases and rings, and these do not appear to be the problem. The rear base is flush with the bridge and appears to still be flush. All rings were still tight.
The ammo is 165 gr handloads. Each load was electronically measured by myself. I don't think the ammo is at fault.

Could a clang against the rifle's muzzle case teh scope to shift zero? Even if so, surely i would shift and then stay there. Could the clang have damaged the scope which is causing the cross-hairs to move after the recoil of each shot?

I should also mention that there was a bit of rain while we were hunting and the rifle's wood stock may have gotten very slightly damp. Could this cause a problem such as this?

Any suggestions?

Thanks

**kayaker** · 24-03-2010, 17:03

Umshiniwam,

I recently had a similar issue. Mine was with a Bushnell Legend 2-7 that I first had on my .303 then on a .308. It would group well at first, then at each rnage session the groups would still be tight but shift wildly. Once it went onto the .308 it just started to spray shots all over the place.

The rings were lapped and tightened to 20 in/lbs of torque, I did not damage the scope by gorilla fitting

. The cheaper Bushnells have a reputation for having poorly assembled reticle erector assemblies that just crap the bed sometimes.

So - check the mounts, this is the first and easiest step. The check the stock is not touching the barrel. Check the muzzle crown to see if it was dinged and look closely for burrs on the end of the lands. If all of these are OK, try a different scope, to me it sounds like your Banner is toast.

I replaced my Legend with an Elite 3200 and so far so good. That was also the second time in my hunting life that I 'paid' the price for a low end scope, the first one was Bushnell Sportsman on my old .30-06 that snapped a cross hair while in a bakkie rack. I used to have a Lynx Professional and I abused it for some years with no issues.

Good luck
Brian

**Blunderbuss** · 24-03-2010, 17:59

Umshiniwam,

Does the rifle have open sights?
I was advised, when I first got my rifle, if I suspected there was a problem with the scope, to check accuracy over the open sights first. If that was problematic, then we looked at the bedding etc. If the accuracy was fine, then an alternative scope was fitted and tested. This advise was from a work associate who was fanatical about achieving clover leaf groupings.

Cheers
Simon

**umshiniwam** · 24-03-2010, 18:11

Thanks for the advice guys. I will follow and let you know.

**jagtersdok** · 24-03-2010, 20:24

Im not a Bushie fan, but I do know that they are not too bad. Before blaming the scope always check the whole rifle, the action screws etc. If all is fine and bases and rings are fine then go to the scope. I don't know how your friends rests or holds the rifle over the shooting sticks, because that definately also plays a big part. Maybe the thump shifted the action a bit loose on the stock, I have seen that happen before too.

**kayaker** · 25-03-2010, 02:47

Ja, start with the easy and cheap solutions.

Not all Bushnells are the same, as you know.In fact they are so different they may as well have different names.

The Banner and Sportsmen are low-end have a spotty reputation, I have an ancient Banner 4-12 on a .22. Its OK but shows it age and is slowly falling apart, but still works!

The Legend I had was OK, made in Philippines but, from day one the adjustments felt soggy and indistinct. It was very crips and clear though! I got the Elite 3200 as a warranty replacement. The 3200's are the next step up are the 'lowest end' of Bushnells better scopes; they are Japanese made. They are not a bad price. Once you get into the 4200 series these are quite expensive.

**Dimitri** · 25-03-2010, 11:52

Umshiniwam,

Besides the scope (which I think may be the problem), you should also consider bedding the rifle. When you say the rifle got slightly damp, what exactly do you mean? Having the stock absorb a "slight dampness" over a medium/long period of time may have lead to the stock swelling and the resultant uneven pressure of the "swelled up" stock on the barrel could cause problems with accuracy.

This happened to an uncle of mine who was hunting in damp, misty conditions in Greytown. His rifle, which had been shooting very accurately for years, was suddenly all over the place. A good bedding job seemed to sort it out.

I suspect that the opposite can also happen i.e. after spending 3 or 4 days in a super-dry environment like the kalahari, your stock may dry out and warp slightly, thus resulting in potential accuracy problems.

Good luck with sorting it out.

**umshiniwam** · 25-03-2010, 12:27

Originally Posted by Dimitri

Umshiniwam,

Besides the scope (which I think may be the problem), you should also consider bedding the rifle. When you say the rifle got slightly damp, what exactly do you mean? Having the stock absorb a "slight dampness" over a medium/long period of time may have lead to the stock swelling and the resultant uneven pressure of the "swelled up" stock on the barrel could cause problems with accuracy.

This happened to an uncle of mine who was hunting in damp, misty conditions in Greytown. His rifle, which had been shooting very accurately for years, was suddenly all over the place. A good bedding job seemed to sort it out.

I suspect that the opposite can also happen i.e. after spending 3 or 4 days in a super-dry environment like the kalahari, your stock may dry out and warp slightly, thus resulting in potential accuracy problems.

Good luck with sorting it out.

Thanks Dimitri.

The rifle is glass-bedded. There was about half an hour's rain while my mate was hunting in the veld. I was not with when it got wet but I don't think it was soaked.

**Wismit** · 25-03-2010, 13:26

A friend of mine also had such a problem. He fastened the screws of the scope mounts again and the problem was solved.
Try it and good luck.

From the photos in the other thread it doesn`t look as if you had too much problems. Great man !!!

**Animal** · 25-03-2010, 13:41

The best would be to get the rifle to a good gunsmith to check it out. Then any of the maybes could be checked out and fixed!
If they guy you talk to have long stories drop by the shop and we will sort it out for you! I know the guys from Bushnell well so if it is the scope we can get them to have a look at it for you too!
Kalahari Arms cc 011-795-1100