Gamo sighting changes every day

[CleanAir]

I pulled out my couple year old Gamo varmint with the supplied scope and set up a target spot in the back yard.  Target is 25 yards and I'm using a bipod.  The scope is nice and tight as is the trigger adjustment screw.  Day 1 I sighted in the scope and shot about 3 groups of 5 which were all reasonably grouped within the 1.5" circle.

Next day with a fresh target, all my shots were off both vertically and horizontally maybe an inch in one direction and 1/2in in another but still reasonably grouped.  I readjusted,  and shot 5 to 10 groups of 5 shots and things were good.

Next day, same story.  Had to re-adjust the scope and then several groups of 5 shots were good.

Today...  same story again.  Everything was going 2 inches high and 1/2" to the left...  so I readjusted again and all was good.  I'm baffled and the only thing I can think that is different is the temperature outside. 

 

[19Sheridan57]

   I am sorry you have had to wait so long for a reply.
     I am NOT an expert with these type rifles, but can offer some tips, til someone with more knowledge comes along. The supplied scopes on air rifles, are almost always junk. They help with sales by making you think you got a great combo. Same thing with exaggerating the fps on rifles. I usually will remove the scope with a new purchase, as soon as I get it. Does your rifle have rear iron sights ?? If so, remove the scope & set those sights . If not , another GOOD scope , usually $60 up , will be what you need . Also, if this is your first break barrel air rifle, read all you can about how to learn to shoot them. These are much different to shoot than a BB , or .22 bullet rifle.

[NHGuide]

The fore-end screws on almost every one of my synthetic-stocked Gamo break barrels need checking after 30  or more shots. I generally don't put loc-tite on them but in a couple of cases, I have had to in order to keep the point of impact consistent.  That's the only thing I can think of other than the lower quality scope they often come with.  I gifted a 'Big Cat' to my brother and within 50 shots the wire reticle was all twisted and broken inside.  A new scope with an etched-on-glass reticle solved his problem.

[19Sheridan57]

   Thanks.
 I forgot to mention those screws.

[Back_Roads]

 I have a friends Gamo Swarm in the shop for a look, my first things to check are the screws, then see if the scope stays zeroed, if not I will get them a good replacement.

[CleanAir]

Well those are all good clues, thanks everyone.  I will first try another scope and if doesn’t solve it I’ll try another air rifle before working on my shooting techniques.  I thought I was a consistent shooter but time moves on and things could have changed.

[19Sheridan57]

Well those are all good clues, thanks everyone.  I will first try another scope and if doesn’t solve it I’ll try another air rifle before working on my shooting techniques.  I thought I was a consistent shooter but time moves on and things could have changed.

     I would check those screws first. If it is the scope, cheap scopes are cheap for a reason. They may work fine on a BB rifle, but high powered pellet rifles will kill one in a hurry. Look for an " Air Rifle Rated " scope.

[Back_Roads]

 The Gamo I looked at had the mounting rings all wrong any way one could, and the turrets were turned all tight in  I remounted it and all is well until the scope fails. This is a lower power Gamo Swarm Whisper, 700 fps 14.3gr. pellet gun so scope may last a bit longer than a higher power break barrel.

[HPP-Mechanic]

I have this older, ugly Daisy 1000; its actually a Gamo,says "Made in Spain". This gun was spring-powered and shot 850ish. fps. It had the "twang" and quite a kick.  Then I decided to see how nice I could make it.  I installed a CDT gold trigger, re-finished the wood stock, fit a threaded adapter on the barrel...  The, I stumbled across a gas-ram conversion kit on Ebay, from Australia.  Power went slightly up, the shot cycle is noticeably faster, as you dont even notice the rifle move when shot. It got louder, and now wears a Buckrail moderator. But now, this thing is murdering scopes. Its killed a Hawke & a Hammer's scope. These are cheap scopes, but many have them survive on springers. The hammers scope mount failed first- slid back & stretched out at the dove tail end. Then I mounted a Zero-Recoil mount. Even with this mount, its killed 2 scopes!  With the gas-ram, the gun is less hold sensitive, and the recoil is less noticeable.  I tend to think that its the speed of the shot cycle, from a gas-ram, that kills the scope.

[CleanAir]

So Frank, when you say that "the rifle killed the scopes",  what is the indication?  Is it like what I experienced where the shot groups wandered from day to day or something else more concrete showing you that the scope is definitely roached?

[avator]

"Killed" scopes won't hold zero.

[CleanAir]

Hi Bill.  I guess what I'm getting at is that if one is having wandering shot groups as in my situation, is it definitely the scope that is the problem or could it be something else?  That's why I was asking if there was some other clear indication that the scope is broken... not holding zero or killed.  I feel like I'm just assuming it is the scope without being able to test it or see something that is broken because I don't know how to do it. 

If I put another scope on my rifle and then had the same issue of wandering groups it could either be that I killed a second scope...  or it could indicate that there is some other issue.  I'm not sure but I'd like to hear how you guys determine that it's definitely the scope.  Maybe you just know your ability with the gun and have a sense for it?  If this issue happened with the Turkish Winchester I've had for 20 years, I would have that sense but with this Gamo, I don't have the time in the saddle. 

I guess I'm used to being able to see or determine what's broken when something is not working.

[caudie]

"Killed" scopes won't hold zero.

To me, the quote from Bill, means:

Try it on another gun, if it holds Zero - it ain't "Killed".

[ER00z]

I had similar issues when I first got into adult airguns/break barrels... Got hooked by the marketing hype of Nitro Piston airguns, had a new (at the time) Nitro Venom Dusk and a fancy UTG/CenterPoint scope... Ended up with many more airguns and scopes.

Long story short, it's most likely the scope. My suggestion would be a new optic. There are some budget options that work out well on piston guns, I've had good luck with Daisy's 4X32AO scope and a Pinty 4-16X40AO scope, either could be had under $70. There are probably many others for under $100 that work as well, but these two have proven themselves on my stronger springer/gas piston airguns.

Links to help identify models... Not necessarily an endorsement, just convenient. Check around for pricing/availability
(these didn't work, you'll have to add "https://www." )

amazon.com/Winchester-Daisy-Outdoor-Products-Scope/dp/B002QB5E52/

amazon.com/Pinty-4-16X40-Illuminated-Flip-Open-Sunshade/dp/B01LXZCD4I/   

If you have a larger budget there are plenty of decent options and often those come with lifetime warranties. I like Burris scopes, not everyone likes their reticles and not all models have parallax optimized for traditional airgun ranges. I personally use and like these on springers/gas rams, can be had under $200... Just keep an eye out for sales.

amazon.com/Burris-Optics-Fullfield-Riflescope-4-5-14x42mm/dp/B019KDSRBG/

amazon.com/Burris-Fullfield-2-5-10x42mm-Hunting-Reticle/dp/B08HR9NNC3/

These days there are many options that are "springer rated". I picked up a discontinued/clearance Tasco scope for $20 that's lasted a few years on my HW95 and yet had a $150 springer rated scope fail in under 50 shots, so you never really know. All of the scopes I've referenced above have lasted on my "magnum" class piston guns that make 24fpe to 28fpe, but by no means are they the only one's that'll hold up. There are plenty of good options from UTG/CenterPoint, Hawke, Hammers and etc. (just listing a few). Just look into what kind of warranty is offered and make sure to read the fine print.

[ER00z]

Hi Bill.  I guess what I'm getting at is that if one is having wandering shot groups as in my situation, is it definitely the scope that is the problem or could it be something else?  That's why I was asking if there was some other clear indication that the scope is broken... not holding zero or killed.  I feel like I'm just assuming it is the scope without being able to test it or see something that is broken because I don't know how to do it. 

If I put another scope on my rifle and then had the same issue of wandering groups it could either be that I killed a second scope...  or it could indicate that there is some other issue.  I'm not sure but I'd like to hear how you guys determine that it's definitely the scope.  Maybe you just know your ability with the gun and have a sense for it?  If this issue happened with the Turkish Winchester I've had for 20 years, I would have that sense but with this Gamo, I don't have the time in the saddle. 

I guess I'm used to being able to see or determine what's broken when something is not working.

Sometimes scopes just lose the ability to hold a zero. They can be re-zero'd and after "X" number of shots they start to drift or with some jolting/bumping around they're just off.

Sometimes the internal springs break or come lose. When this happens, you can try to adjust the turrets to re-zero and either the point of impact doesn't change or is wildly inconsistent, can miss your target completely.

Sometimes scopes just get beat to a pulp on spring/gas piston guns. It's not all at once, but many little jabs. Wire reticles can break/rotate, adjustable objective lense retaining rings can back off, cap-less turrets with resettable zero can have the turret screws back out/fall to the ground and lose the turret knob, scope internals can just break (tubes, lenses, springs & etc.)

Sometimes I say sometimes too many times... But having open sights is always a plus, alternatively look into a "See All sight" (just know it's not for everyone)

Cheap scope turrets generally don't track well (meaning adjustments are sloppy, more or less). I'm sure there are plenty of videos that can be found which can explain scopes, good vs not so good, how to check for failure & etc. much better than I can type here.

Wish you the best of luck

[avator]

Other things can be wrong and checked.
Make sure your scope is not slipping in the rings or the rings are not slipping on the dovetail grooves on the gun.
Make sure the rings are actually in the grooves on the breech and the screws are tight.
Make sure your stop pin on the rings it set in the hole on the breech if you have one.
Make sure your not clipping at the muzzle break or ldc if you have one.
Do a tissue test to see if the breech seal is leaking.
Do a chrono test to see if the piston seal is leaking.
If you have another break barrel gun you and try the scope on that... it's possible that the scope will not act the same on a gun without recoil (pumper, C02 or PCP).
Try shooting the gun for accuracy with open sights.
If it's any of these things you would be wasting your money buying a new scope.

[Tater]

Did you ever check the fore-end screw for tightness?

[Rocker1]

 Sounds like scope or screw issure to me.  David