Change in Zero of Fwb 700 alu

[snapy050]

Hi fellow shooters!

I have been shooting with my fwb 700 alu from past 4 months.. I have noticed that the Zero of the rifle changes with the usage of air..

For example.. When I start shooting with 200 bar, I set The rifle to 10.9-10.8 in my sighters.. but then when I am shooting 60 shots continous, on about 175 bar, I feel that the zero changes at about 7 'o clock.. to may be 10.3- 10.4.. later when I reach to 150 bar, I start getting a few 9's when I realise and give some clicks to counter that..

Mind you this is only an example.. I also start sometimes at 175 or 150 bar.. So can you guys plesase give me a detailed explaination on how this zero changes and at what pressure it changes in your rifle if it does.. Please specify whether u use walther, fwb, anschutz or other brand while you explain your point of view..
Once I have lot of replies, I will reveal a little more of my knowledge that can help your shooting.. So kindly contribute and help to better the shooting sport on the whole!

Rajesh Manpat
Indian National Shooter

[cdf]

It is not at all inconcievable that we could be talking about eye fatigue . A second possability is muscle fatigue . The late Don Nygord described the problem in a pistol shooting context . We could also be seeing sensory adaptation of your trigger finger .

Have you tried shooting from a rest at different pressure readings ?That is probably the only way to prove or disprove . If the problem is confirmed by results obtained from a fixed rest , it could be that your regulator is non linear ( not dispensing the same pressure at differing tank pressures ) .You might also try to check out whats happening on a chrony .

Chris

[snapy050]

It is not at all inconcievable that we could be talking about eye fatigue . A second possability is muscle fatigue . The late Don Nygord described the problem in a pistol shooting context . We could also be seeing sensory adaptation of your trigger finger .

Have you tried shooting from a rest at different pressure readings ?That is probably the only way to prove or disprove . If the problem is confirmed by results obtained from a fixed rest , it could be that your regulator is non linear ( not dispensing the same pressure at differing tank pressures ) .You might also try to check out whats happening on a chrony .

Chris

But then when I give some clicks when it hits 10.3, I get back the good 10's unless i do a major mistake, its always a good 10! Do you still think its about fatigue..

And about checking the pressure over rest.. Will try it out next week and post the results.. Until then please keep the discussion alive as its one of the most important doubts that a beginer can get when he starts air rifle.. knowing that the zero of the rifle dosent change throughout the match.. is a major morale booster and gives a lot of confidence in shooting.. Lets hope that the results turn positive and the group does not change..

Next week I have decided to conduct tests mounted over bench rest.. first at 200 bar then 175-150-125-100-70

I will be shooting 2 groups of 5 shots in 2 different cards and will post the pics of target.. any other suggested ways of testing? please post fellas...
And keep your thoughts coming.. as i feel encouraged to solve it for you and for myself..

[Jose Rossy]

Next week I have decided to conduct tests mounted over bench rest.. first at 200 bar then 175-150-125-100-70

I will be shooting 2 groups of 5 shots in 2 different cards and will post the pics of target....

I think that's a sound plan. If you can mount a scope, so much the better since you are not interested in shooter-induced effects for this particular test.

Agree that a wandering zero is a major headache.

[Richard H]

It is not at all inconcievable that we could be talking about eye fatigue . A second possability is muscle fatigue . The late Don Nygord described the problem in a pistol shooting context . We could also be seeing sensory adaptation of your trigger finger .

Have you tried shooting from a rest at different pressure readings ?That is probably the only way to prove or disprove . If the problem is confirmed by results obtained from a fixed rest , it could be that your regulator is non linear ( not dispensing the same pressure at differing tank pressures ) .You might also try to check out whats happening on a chrony .

Chris

But then when I give some clicks when it hits 10.3, I get back the good 10's unless i do a major mistake, its always a good 10! Do you still think its about fatigue..

And about checking the pressure over rest.. Will try it out next week and post the results.. Until then please keep the discussion alive as its one of the most important doubts that a beginer can get when he starts air rifle.. knowing that the zero of the rifle dosent change throughout the match.. is a major morale booster and gives a lot of confidence in shooting.. Lets hope that the results turn positive and the group does not change..

Next week I have decided to conduct tests mounted over bench rest.. first at 200 bar then 175-150-125-100-70

I will be shooting 2 groups of 5 shots in 2 different cards and will post the pics of target.. any other suggested ways of testing? please post fellas...
And keep your thoughts coming.. as i feel encouraged to solve it for you and for myself..

Actually yes it still sounds like fatigue because you keep using air so it should keep moving down if that is your thesis. The only other thing you could do is cHrony it and see if the velocity changes.

[cdf]

Eye fatigue combined with a wee bit of dehydration could screw you up , when you break and click your sights , you are resetting your brain and taking a break .

If you shoot as bad as Richard H or me all tens are treated equal .

Air rifle is a very demanding discipline , you can only maintain physical and mental focus for a certain amount of time .

Chris

[Richard H]

Speak for yourself, shot a 99 and a 97 at the match last night. Shot 560 in AP today. The riflle is definately helping the AP shooting.

[cdf]

How can belly shooting help your AP , other than teaching you how to take napps between shots . I've got to give it a try .

Chris

PS: G.H. must be coaching ya.

[Richard H]

Like I said before I've been in training for prone since Kindergarten when we use to take our towel so we could lay down and have a nap. At the time I didn't know it but I was working on my position.

[snapy050]

In fact I had the same doubts.. but my scores tend to get better towards the end of the match.. Every match I have shot.. I have had my best card towards the end.. Usually its a 100 or 99.. So no questions about loss of fatigue.. I also learn to relax between shots so as to reset my mind and body and spend a few seconds to remember the last shot that hit a 10.. I begin to do exactly same procedure for the present shot.. So overall.. I do not struggle with fatigue whether body mind or eyes.. Hence I am very much interested to know how my rifle behaves during the corse of the match..

I also shoot .22 prone and 3 positions.. There I use anschutz 1903 model and I face huge problems with wandering zero.. It is said that mine is a cold barrel which means that I have to shoot without resting the barrel.. Each time I have to relax, I have to put an empty case in the chamber.. you guys might say that Its the case with every barrel as they are all metal made.. But mine shoots 4 o' clock 5-6 if I leave the barrel open to air circulation..

So the difference is not much in an air rifle.. but as you guys know.. every 10 counts..

[cdf]

The only way to prove or diprove is a bench scession , preferably with a chronograph , firing test strings at various bar readings . You are a good enuff shot to pick up on stuff the rest of us wouldn't notice . You obviously have a lot of talent to be producing these kinds of scores without jackets etc .

One of the symptoms of a doubtfull regulator is wide velocity fluctuations .

Chris

[Guest]

About a year ago I posted the same issue on this forum. My FWB700 would change it's point of impact as the pressure would change. I confirmed this on the bench using a 20x scope at 10 and 20 meters. As I remember, as the pressure would decrease the POI would drop about 5mm full pressure vs. meter touching the yellow. I solved the issue by frequently filling but this should not be happening with this quality of gun.

[Thomas Monto]

When we were at the PARA World Championships in Sargans Switzerland this past summer, there was a gunsmith there.

He would shoot the rifle over a snail type chronograph and if the rifle (pistol) did not meet specs. he would tear it down. Replaced the seals, checked the regulator with a pressure gage using the rifle's air cylinder. If the gage did not register correctly the regulator was removed an a new one installed (and rechecked). Also the cylinder was checked (mostly for broken pressure gages) and if it did not meet specs it was torn down and repaired. Next he checked the trigger and properly adjusted it (I presume for sear engagement and weight). The rifle was then tested over the chronograph, adjusted as necessary, reassembled and tested again. All of this took about 15-20 minutes and cost about $40.00 equalivant US. Compare that with what is charged in the US. Last time we had one rebuilt in the US it was a $100, (plus $100 shipping) and they did not do as through job. In fact the one I recall had to be sent back as the trigger was completly messed up. Another rifle sent in twice still has the rifle fire on occasion when the gate is closed.

The result of the rebuild was the rifle grouped better. This may have been a mental reason, rather than actual group, but whatever works for the shooter giving confidence.

TM