How to set Zero in a air rifle

All posts related to air-guns (air-rifles, airsoft, air-pistols, air-guns etc.).
Grumpy
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Re: It just wont shoot straight

Post by Grumpy » Tue Nov 06, 2007 5:29 pm

If it`s smoking it would appear to be dieseling. Dieseling causes variable velocity but doesn`t affect accuracy as much as you imply.
Dieseling is bad news as it damages seals and knackers the spring - causing it to go `soft` and lose power.
If you shoot few shots at precisely the same spot does it group them together - albeit at a different location from where you are aiming ?
If it does it isn`t a problem of inaccuracy as such, rather that the sights need adjusting - requiring some machining or packing from what you say - or the barrel isn`t square to the action. Hopefully the former.
A bent barrel is also possible - but those are only usually found on cheap Chinese air rifles . A bent barrel will squirt shots around all over the place.
Grandpa Mack The Knife will sort you out.

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Mack The Knife
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Re: It just wont shoot straight

Post by Mack The Knife » Tue Nov 06, 2007 7:04 pm

Grumpy";p="30396 wrote:A bent barrel will squirt shots around all over the place.
No it wont. Infact you can get almost match grade accuracy. Feiwerkbau made a special air-pistol based on the FWB 65/80 using a long barrel that was bent into a complete circle to prove the point.

What can affect accuracy greatly is a damaged muzzle crown. I know you know that but that's another point that I would like Sid to check. Sid make sure the gun is unloaded and uncocked and then carefully check the muzzle crown (the business end of the barrel) for burrs or scrapes. If you see any, have the gunsmith recrown the muzzle.

Sid if the rifle is already grouping well then all you have to do is adjust the sights.

You will see two adjustment knobs. One on top which has numbers stamped on it and another to the right and rear of the rear sight. The former adjusts the elevation (up and down) and the latter the windage (left or right).

If your point of impact (POI) is lower than the point of aim (POA), raise the rear sight by loosening the elevation knob in an anti-clockwise direction - no more than half a turn at a time. Preferably lesser. The reverse is the case should the POI be above the POA.

The windage knob works on the same principle as the elevation knob.

Gramps.

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Post by Sid_kapur30 » Tue Nov 06, 2007 7:37 pm

Grumpy";p="30396 wrote: If it`s smoking it would appear to be dieseling. Dieseling causes variable velocity but doesn`t affect accuracy as much as you imply.
Dieseling is bad news as it damages seals and knackers the spring - causing it to go `soft` and lose power.
If you shoot few shots at precisely the same spot does it group them together - albeit at a different location from where you are aiming ?
If it does it isn`t a problem of inaccuracy as such, rather that the sights need adjusting - requiring some machining or packing from what you say - or the barrel isn`t square to the action. Hopefully the former.
A bent barrel is also possible - but those are only usually found on cheap Chinese air rifles . A bent barrel will squirt shots around all over the place.
Grandpa Mack The Knife will sort you out.

Uh oh - "This Account Has Exceeded Its CPU Quota" ( AGAIN. )
if i shoot 5 shots at a specific point i would get the very 5 shots together rather nearby each other (thats due to my aim) at the lower corner of the target but in the same line (not to the left or right of the point where i aimed just lower)

Thanks
Sid

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Post by Sid_kapur30 » Tue Nov 06, 2007 7:38 pm

Mack The Knife Bana";p="30404 wrote:
Grumpy";p="30396 wrote:A bent barrel will squirt shots around all over the place.
No it wont. Infact you can get almost match grade accuracy. Feiwerkbau made a special air-pistol based on the FWB 65/80 using a long barrel that was bent into a complete circle to prove the point.

What can affect accuracy greatly is a damaged muzzle crown. I know you know that but that's another point that I would like Sid to check. Sid make sure the gun is unloaded and uncocked and then carefully check the muzzle crown (the business end of the barrel) for burrs or scrapes. If you see any, have the gunsmith recrown the muzzle.

Sid if the rifle is already grouping well then all you have to do is adjust the sights.

You will see two adjustment knobs. One on top which has numbers stamped on it and another to the right and rear of the rear sight. The former adjusts the elevation (up and down) and the latter the windage (left or right).

If your point of impact (POI) is lower than the point of aim (POA), raise the rear sight by loosening the elevation knob in an anti-clockwise direction - no more than half a turn at a time. Preferably lesser. The reverse is the case should the POI be above the POA.

The windage knob works on the same principle as the elevation knob.

Gramps.
tried to adjust the points but the sight dont move up or down only its more like me just turning the knob for no good reason but shall try doing it half a point at a time see if that works :) plus i didnt notice any scrapes or any thing unusual at the firing end of the barell but will check them again tonight

Thanks
Sid

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Post by Mack The Knife » Tue Nov 06, 2007 7:45 pm

tried to adjust the points but the sight dont move up or down only its more like me just turning the knob for no good reason but shall try doing it half a point at a time see if that works :) plus i didnt notice any scrapes or any thing unusual at the firing end of the barell but will check them again tonight.
In that case, show it to the Delhi boys (perhaps you are doing something wrong) or take it back to the shop and ask for a refund or a replacement.

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Post by Sid_kapur30 » Tue Nov 06, 2007 10:06 pm

shot 3 groups of 5 shots each marked the area which i aimed for and have circled the area where i got em . Shot them right now on my roof using a little help from my kitchens tube light (it's dark)

will post the pics tomorrow :D

Cheers
Sid

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Re: It just wont shoot straight

Post by Grumpy » Tue Nov 06, 2007 10:12 pm

"Grumpy wrote:
A bent barrel will squirt shots around all over the place."

"Mack The Knife wrote"
No it wont. Infact you can get almost match grade accuracy. Feiwerkbau made a special air-pistol based on the FWB 65/80 using a long barrel that was bent into a complete circle to prove the point."

Oh yes it will. There`s a world of difference between the application of physics and mechanical engineering to a deliberately curved match barrel and a clunky plinker that has bent because of the application of brute force and ignorance - and the crappy grade of steel used. I had a Chinese air rifle with a bent barrel and at ten yards it would fill a 20" circle with randomly placed pellets.........and occasionally it would launch them outside the circle.
The deliberately curved match barrel has a constant curve and constant bore - although there are variations which used a modified curve - a variable radius decreasing towards the muzzle - however the bore is still as constant as possible. Bend a barrel and the curve is both non-constant and you distort the bore which is anything but constant. Apart from anything else the irregular bore distorts the pellet which is then re-distorted back into an approximation of its original form......which isn`t exactly condusive to accuracy.
Curved barrels have aldo been used in some .22 lr and centrefire rifles ..... with varying degrees of success. One of the main requirements is a short bullet.
On the subject of curved barrels ; Have you ever seen a picture of the German WWII `Krummlauf` device ? Almost exlusively fitted to the Sturmgewehr 44 assault rifle although initially developed on the Gew 98 but it was found that the long bullet presented problems which didn`t occur with the bullet used in the 7.92 Short cartridge used with the StuG 44. It was a curved barrel extension designed to allow shooting around corners or over the top of trenches etc. Made in three different curves: The `J`, 30 degrees: The `P`, 90 degrees and the `V`, 40 degrees although only the `J` was made in any quantity.
I did think about a damaged crown but that also tends to spray shots around indiscriminately.......depending on the amount of damage. With a drop of over a foot ( from the sound of it ) and reasonable groups it won`t be a damaged crown. Its either sights - most probable - or an incorrectly machined/fitted barrel.
I absolutely agree that it should be returned to the vendor. Why spend time, effort - and possibly money - on fixing an item that isn`t right ? You wouldn`t accept a new car that wouldn`t drive in a straight line would you ? A gun that doesn`t shoot straight is an ornament......or a club.

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Post by Mack The Knife » Tue Nov 06, 2007 11:19 pm

Grumpy,

Why did you get out of bed! :mad:

Okay, let's leave the FWB 65/80 aside and take an airgun who's barrel has bent slightly due to the shooter touching off the trigger when the barrel was still in the 'broken' position. I have seen and shot such airguns and the accuracy does not suffer. The only thing that changes is the point of impact.

Now if you are refering to some severe bends then I would be surprised to see the pellet exit leave alone there being any semblance of accuracy. However, that is not what we are talking about.

Good night! :mrgreen:

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Post by Sid_kapur30 » Tue Nov 06, 2007 11:19 pm

Hey guys i finally managed to get the rifle shoot at the correct height had to turn the knobs atleast 8 times (anticlockwise) and wallah
i think i was turning it clockwise till now :oops:

now adjusting it for its slugs going towards right :)

Thanks a ton
Sid

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Re: It just wont shoot straight

Post by Grumpy » Wed Nov 07, 2007 12:13 am

"It just wont shoot straight".

Until the sights are adjusted.

I think I`m about to suffer an attack of hysterics !!!

Dodger, you know that I only come here to annoy you. Disagreeing with you is the highlight of my day !

( Now I`m really having hystrics ! )

:D :shock: :roll: :cry: :P :twisted: :lol: :oops: 8) :idea: :idea: :evil: :( :o 8) :? :roll: :wink: :idea: :mrgreen: :idea: :P :?: :!:

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Post by Mack The Knife » Wed Nov 07, 2007 9:51 am

Hehehehe...

Vikram, just how old is Grumpy? The truth this time, please!

Sid, glad you figured it out. You chump! :mrgreen:

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Post by dev » Wed Nov 07, 2007 10:52 am

Sid_kapur30";p="30441 wrote: Hey guys i finally managed to get the rifle shoot at the correct height had to turn the knobs atleast 8 times (anticlockwise) and wallah
i think i was turning it clockwise till now :oops:

now adjusting it for its slugs going towards right :)

Thanks a ton
Sid
Kya insaan hai tu. :lol:So much noise because you didn't know how to use the horizontal and vertical correction screws?
Good that you figured it out and hope that you will enjoy the rifle.

Dev
To ride, to speak up, to shoot straight.

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Post by Mack The Knife » Wed Nov 07, 2007 11:20 am

He obviously has poor teachers in Delhi...

Ahem!

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Post by Sid_kapur30 » Wed Nov 07, 2007 12:10 pm

well i was turning it clockwise till now how was i suppose to figure out anticlockwise ghumana hai aur woh windage wala screw ghumane par bhi move nahin kar raha woh i'll show some one in person.
and thought the point marked as 1 means it zeroed for 10 meters :( i was clueless about you still having to adjust it
but i know that i shout have experimented more

Thanks
Sid

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Re: It just wont shoot straight

Post by Grumpy » Wed Nov 07, 2007 12:47 pm

I have this vision of Sid now ........ a very nice bloke but just a little thick ( `Sid Nice but Dim`............. I don`t suppose any of you will understand that reference......)
Is Delhi a bit like Norfolk ?
Norfolk is generally reckoned to be the dimwit capital of Britain - allegedly because of certain habits in the past. Norfolk is rather sparsely populated so it used to be a long way to walk to find an unrelated wife...........so people didn`t bother. Alledgedly.
Sorry Sid.
Glad you sorted the rifle.

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