Possibly stupid question about scope staying zeroed

B

Botswana

New member
Ok, a vast majority of my shooting experience has been through open sights. I've shot rifles through a scope, usually a bolt-action, but always loaner guns.

I recently inherited a Marlin 30-30 with a scope mounted on it. I know the scope was zeroed but the gun has been sitting in a gun cabinet for close to 30 years, not counting a few trips in transit. It's well overdue for a good cleaning but there is no rust so the gun itself is in good shape.

I'm curious though, would the scope still be zeroed after all this time?

I'm about to invest in a bore lasersight anyway for a variety of reasons, just wondering if I should expect any accuracy out of this thing after so many years. Once zeroed always zeroed?

You think this sounds ignorant now, wait till I actually have to zero an optic.
 
The internal parts of the scope shouldn't have shifted relative to one another, so as long as the mechanical connection between the scope and the rifle hasn't been knocked out of alignment, you should still be pretty close.

I'm not saying for certain that it will still be perfectly zeroed after thirty years, but if it's "off", it's probably no more off than it's been for the past 29 years.
 
Caution when using some bore sighters: they can make you think you are way off when you're really not at all. I have mixed results with a couple brands and certain calibers. In my latest case the inserted end snagged the 30 cal rifling making the laser point off to one side. Figuring this to be the case, I did not dial the scope in until I test fired at the range. It was not off like the bore sighter indicated. I can pretty much tell when the bore sighter is right or wrong. I could feel the small plastic insert drop into some grooves on one side. That's why I didn't adjust the scope to line up with the pin point red dot.
 
Once zeroed always zeroed?
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If only that were true. I used to hunt with a group who believed that. They were all older than me and were better shots than me, all them had military backgrounds. Every year I would question them to see if they sighted in their gun and every year their answer was the same, "it shot straight last year so it should this year". Their lesson came on the final year we hunted together, we all got to watch a nice 4X4 mule deer run across a flat as one of our party shot, and shot, and shot. He emptied his gun, reloaded and repositoned, and missed 2 more times before the buck finally made it to safety. Once back at camp we setup a target at 25 yards and found out the gun was shooting at the 5 o'clock position, 6" from the bullseye. He took the gun in after the season and the gunsmith said his stock had warped causing the zero to shift.
 
...I recently inherited a Marlin 30-30 with a scope mounted on it. I know the scope was zeroed but the gun has been sitting in a gun cabinet for close to 30 years, not counting a few trips in transit...
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Your post implies that you have never shot the gun yourself. If that be true, then the "zero" that was set, was set by someone else. No two people will look trough a scope in exactly the same way. Therefore, it will have to be fired and zeroed by you to get it exact. Also, a gun that has "been in transit", may have been handled roughly, changing the zero somewhat or, even a lot.
 
Assuming the scope has not been severely jarred or bounced around, it will stay where it was put but, as AllenJ says, other factors may have changed the point of impact, so the scope might no longer be "zeroed".

Also, remember that the rifle was "zeroed" way back when with some specific ammunition; unless you have some of that ammunition, the rifle might not shoot to the same place with another kind (brand, bullet weight, velocity). Even if you do have some 30-year old ammo, it might not shoot the same as when it was fresh.

There is no way to be sure of the scope and rifle without sighting in on the range with the ammunition you want to use for hunting.

Jim
 
Bottom line is you well need to zero the scope.

Those laser bore sighters can send you in the wrong direction. Start at 25yds to get one paper and go from there.
 
Good scopes tend to hold their zero, but they should always be checked. Rough handling can definately change the zero, but the only way to tell is to fire the rifle. Put a target out at 25 yards and fire. You should be on paper. If in the black, take it out to 100 and fine tune a bit more. If 100yds is your goal, then finish zero. If not, then move to final distance and dial in.

I would be sure to check all the fasteners before going to the range to make sure they are tight.
 
Odds are that there is unlikely to be any major shift in point of impact compared to point of aim due to any change in the wood from changes in humidity or in using a different brand of ammo. It's just one of those things to check at the range.

Absent some form of abuse, a scope's internal adjustments don't change if not messed with by happy fingers.
 
A good scope should hold its zero. Your gun, absent abuse, should more or less be at its original zero. That being said, the original zero might not be a zero for you.

Bottom line is take it out and shoot it and see where it is for you. As pointed out above, start at 25, go to 50 and finally 100. If you are on paper at 25 and 50 you can tweak it at 100 yards until you are happy with its zero.
 
A thirty year old scope...

was manufactured without the current improvements, so it may not be as durable as current ones. Also, scopes, old or new, have a lot of different levels of quality. Each brand name, and each model line within the brand, will have a different level of quality built in.

In addition to the uncertain ability of that old scope to hold zero, when currently being used in the field, it also will undoubtably be inferior in its ability to gather light, making the image dim in the early morning and late evening - just when you need the brightest image possible. Modern lens coatings were not available 30 years ago, to deal with this problem. Current scopes are available with multiple lens coatings on every surface of every lens. They are described as "fully multi-coated" lens, and denote higher quality optics.

I would suggest trading out the old scope for a new one. Even a $200 new scope should be superior to most 30 year old scopes. Unless it is a Swarovski or some other very high dollar relic from the past. Unlikely, IMHO for a rifle of that type/caliber.
 
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Even very good older scopes can have problems after 30 years. Recently, my favorite Baush&Lomb Balvar 8b had an eyepiece coupled lens separate, causing the image to be ringed with what appeared to be a lace frame. It still shot to POI, but it was time to retire her.

Your marlin will tend to hold zero for many years, unless bumped or someone takes the magazine tube and forend off for cleaning. Screw tension on the forend or magazine tube screws can change POI and group size to some extent. It's not usually much, considering they normally group just under 2" at 100 yards, but perhaps enough to miss small targets.
 
Forget the boresighter. Pull the bolt and set the rifle on sandbags with your target of choice centered in the bore when you're looking through it from 20-30 yards. Then, without moving the rifle, adjust the crosshairs until they're centered on the same target. Go to the range for fine tuning.

At the range, take a shot at 5o yards with the crosshairs centered on your taget. Adjust the gun on the sandbags until the crosshairs are centered on the target again. Then, without moving the gun adjust the crosshairs until they're centered on the bullet hole. You should be pretty close now to start shooting groups and making the appropriate scope adjustments.

In your case, you may find the scope is pretty close to right when you do the first boresighting, but you never know...
 
The problem with older scopes are that many of them used steel springs for tension. The bottom line is that as they get old they loose tension and do not keep a zero. Be mindful when you are sighting in, if you make a correction on the scope and impacts do not change, you may have a problem.
 
Many moons ago,,,

When my Grandfather passed away I had hoped to get his scoped 30-06,,,
It was a Remington something or other model with a Weaver 4X scope.

I was a teeny kid of 5 when he bought it for his "deer rifle",,,
I do remember going with him to the gun store to buy it.

He bought 100 rounds of ammunition that day as well,,,
He said that would last him a lifetime of hunting.

Anyways, a cousin got the rifle,,,
And 20 some-odd rounds of that original ammunition.

Papa sighted it in off the back porch the day he got it,,,
Then it was 1-3 shots a year to get his deer,,,
After that it went back in his gun cabinet.

The point of this story is that the rifle/scope,,,
Held it's 100 yard zero for over 20 years.

Papa wasn't an avid hunter,,,
He just wanted to have venison every now and then.

Neither was he a sport or target shooter,,,
The closest he came to that was rat shooting at the dump with a scoped .22.

But I think that was more about being away from my grandma,,,
With the thermos of "Irish Coffee" he always had with him.

Scopes can hold a zero for years and years on end,,,
Maybe it was the low round count that helped.

Aarond

.
 
Your post implies that you have never shot the gun yourself. If that be true, then the "zero" that was set, was set by someone else. No two people will look trough a scope in exactly the same way. Therefore, it will have to be fired and zeroed by you to get it exact.
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I get told that year after year about my units M16s, that even though theoretically it was zeroed last year, everyone looks through the sights different, etc... We were all taught the same way, though, post centered in peep, target bisected by post. Each year, I walk away from the zero range with my 15 remaining rounds, and a target with a 3 shot cloverleaf through dead center. Granted, I have been lucky enough to not get a rifle used by someone who "does their own thing," but still...

I'm betting, barring rough handling or environmental contaminants, it'll be either zeroed already, or within an inch or two.
 
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