group size

[ds1]

Something strange has happened on the last two training sessons.

 

100m - (problem) I shoot 4; 5 shot groups; of these groups 3 groups have flyers - low left at 7 o`clock. Average group sizze is 1moa including flyers possibly larger, flyers are always in the same place often 2 or 3 shots within a 5 shot group - almost like 2 seperate groups.

 

200m next - 4 groups, 5 shots per group all are fine - 1/2 moa with no flyers.

 

300m next - 1 group 10 shots, easily sub 1 moa with no flyers.

 

Back to 100m - ####### flyers again.

 

Anyone have any idea why I'm getting flyers - always low left at 100m and not at other distance.

 

Many thanks,

 

David.

[brown dog]

Is it the same 'everything' at all ranges? Position, rests, ammo batches etc

[ds1]

Yup, everything the same. No changes in magnification, set up or ammo.

 

Guessing if it could be parallax at 100m (scope nxs 12-42x56 - set at42x) possible parallax and best focus could be different at 100m, less critical at 200m+.

[Streeker59]

Are you using boat tails. I read an article once that suggested that some BT's require at least 200 yards to settle. The evidence was that this guys rifle and ammo combination would not print tight groups at 100 yards but would take the goolies off a knat at any distance beyond 200.

 

Have you tried flat based bullets and do you get the same result?

[Barrelsniffer]

Are you using boat tails. I read an article once that suggested that some BT's require at least 200 yards to settle. The evidence was that this guys rifle and ammo combination would not print tight groups at 100 yards but would take the goolies off a knat at any distance beyond 200.

 

Have you tried flat based bullets and do you get the same result?

 

 

Ive had same exp as that above using BTs..100yds shite further than 200 blob on ? strange..but then used diff powder to sort the shite out...back to square one

[Chris-NZ]

At the risk of insulting you, how do you set the parallax?

 

The procedure for focussing everything is

- focus the reticle against a blank light background, preferably the sky

- set the parallax by looking at the target with the rifle on a rest. Move your head from side to side and if there is -any- movement of the reticle against the target, readjust and check again. Don't rely on any markings on the scope for this.

 

If your groups are still weird, look elsewhere :0

Good luck.

 

Chris-NZ

[ejg223]

Paper target flopping in the wind???

edi

[brown dog]

Yup, everything the same. No changes in magnification, set up or ammo.

 

Guessing if it could be parallax at 100m (scope nxs 12-42x56 - set at42x) possible parallax and best focus could be different at 100m, less critical at 200m+.

 

David, I'm a bit non-plussed!

 

My first instinct is 'something's been changed' -

 

Just to clarify:

 

What rifle/calibre is this?

 

Has this ammo previously been used satisfactorily at all distances in this rifle? (exactly the-same; no component changes at all)

Have any muzzle attachments been changed (ie anything that could affect gas flow at the muzzle)

 

If it's 'no change' to the preceding 2 ...could it be 'mind' ?

[foxing2night]

Hi David,Sounds to me that your bullet selection what ever it is???. Is not going to sleep at 100 yards?? But it is going to sleep at further distances??

 

What I am trying to say is that it takes longer to stabilize .

 

Common with some boat tail bullets or rifle twists and the FPS that they are doing??

Combo of the three???

 

Darrel

[CliveWard]

At the risk of insulting you, how do you set the parallax?

 

The procedure for focussing everything is

- focus the reticle against a blank light background, preferably the sky

- set the parallax by looking at the target with the rifle on a rest. Move your head from side to side and if there is -any- movement of the reticle against the target, readjust and check again. Don't rely on any markings on the scope for this.

 

If your groups are still weird, look elsewhere :0

Good luck.

 

Chris-NZ

 

Chris,

 

Good advice there. Zero parallax and best focus are not the same on some optics. You need to check for parallax as you have described.

 

 

Cheers

 

 

 

 

 

Clive

[CliveWard]

Hi All,

 

Just out of interest has anyone anywhere done any testing with accoustic screens to see if this assumption about bullets needing range to stabilise is true?

 

I'm quite sceptical about it that bullets that are on a diverging course away from the point of aim at 100 yards will then somehow steer themselves back onto the point of aim at say 300

 

 

Cheers

 

 

 

 

 

Clive

[MarinePMI]

Clive,

 

I haven't used screens, but I have watched many a vapor trail in my day. It always amazes me how much a bullet moves around in flight, and yet consistently hits the near same point of impact...

[ds1]

Thank you for the help and advice, a little update after another range session:

 

.bullets are 155 grain Scenars (boat-tail) however in the past they have grouped well at 100m but 167 Scenars are slightly better at 100m but loose out in wind drift.

 

.NXS scope I tried parallax free against best focus, in truth very close at 100m....more critical at 50m, so I dont think that is the issue now.

 

Range session on Wednesday - a different range, I shot at 100m and 200m, barrel was not cleaned. 100m first, dramatic improvement in groups using same neck sized only ammo. 200m respectable with the same ammo but several shots showed vertical stringing. Next I tried body sized ammo - shotgun groups +2moa.

 

In the past body sized ammo has shot slightly worse than neck sized. I know the chamber is big in that barrel and the start of the barrel feels rough . Next step is to try a new barrel - new barrel already now on. Will see if this helps.

 

David.

[Guest ewen]

I think you are just a crap shot.. :-)

[baldie]

I think you've answered your own qustion David.It sounds like your throat is on the way out.

[ds1]

Hi Ewen, we both know that I am a crap shot but this is even crapper than usual.

 

Hi Dave, I put both new and old barrel side by side and put a tightish patch through - new one was smooooth, old one felt like a cheese grater.......old barrel is now off and new one on so we will see next week.

 

David.

[Patriot741]

Hi David,

 

Have you tried a heavier bullet in you rifle ? I had similar results through my rifle with 155gr & 168gr Sierra HBBT's but I'm now using 175gr's and I'm getting tight groups at all distances. I've also got Geoff to try the same load an he's now converted over as well.

 

Derek.

[ds1]

Hi Derek,

 

Great you are on here - solved the problem with a new barrel, now if I could just solve the general crap shooting bit I would be happy. Sods law I was at Holesov on Thursday - groups out to 300m had been sub 1/2 moa from the start. Then I shared a target with Karel at 300m...he was using an old Tanner rifle and 4x scope - he had to lube the rounds to get them to extract. He kicked my ass but good at 300m - I cant wait to be reminded about it every time I go there.

 

David

[Ronin]

Glad youve resolved the problem David, now all you have to do is get that nut behind the butt sorted

 

 

 

Welcome Derek, hope youve finally recovered from neverending bus ride

[Patriot741]

David,

 

That wouldnt be the new barrel you were going to try to fit back in May was it ? I'm glad you've got the problem sorted out though. Karel seems to be able to shoot just about anything. When Geoff and I took Karel to Bisley he did the same thing with every rifle he tried. We told him he's not going again ! Say Hello to Karel for me next time you see him.

 

Ronin,

 

You never get over that coach trip across Europe. Next time I'm going to try locking myself in my Pelicase !

 

Derek.

[baldie]

Welcome Derek, great to see you on here.

Say Hi to Geoff for me.

 

Dave.