parallax error

[hareng]

Whats this Si the Niko or Comp series?

Seen many 60+ where the ret moves with focus adjustment from 'ALL' makes and models. More evident in the warmth or cold with expansion and contraction, erector tube tilts! So far theres only one company to understand the problem, cured 6 years ago and not dependant upon price.

Even when in focus you can and will still get pa error or head bob. Not strictly true BDT its the opposite, look to the left through eye bell, image veers off right when in focus Rob. Have many videos, problem is getting manufacturer to accept theres a serious problem, took me 4 years to get your scope producer to accept Rob no apology or thank you 5 returns over 18 months, plus 2 returns and 5 replacements on first scope. Every other producer dismisses as a problem because they don't test for it.

[Ratinator]

Whats this Si the Niko or Comp series?

Seen many 60+ where the ret moves with focus adjustment from 'ALL' makes and models. More evident in the warmth or cold with expansion and contraction, erector tube tilts! So far theres only one company to understand the problem, cured 6 years ago and not dependant upon price.

Even when in focus you can and will still get pa error or head bob. Not strictly true BDT its the opposite, look to the left through eye bell, image veers off right when in focus Rob. Have many videos, problem is getting manufacturer to accept theres a serious problem, took me 4 years to get your scope producer to accept Rob no apology or thank you 5 returns over 18 months, plus 2 returns and 5 replacements on first scope. Every other producer dismisses as a problem because they don't test for it.

Not got a comp yet , Sunday fingers crossed.
Its on the Mk1 big nikko.
I have run a few tests and I think it may be the twin cone stripper. think its just coincidence that it has happened on two similar targets.
One thing I did notice is I need to set the scope up on the mounts with the windage turret wound in one turn.
When I went round the clock with it far right one turn down went low compared to the others.
I have had big nikkos in the past ,where you could see the ret move when the side wheel it base
And I have known mag ring to get stiff if you have use too much windage.

[RobF]

Not got a comp yet , Sunday fingers crossed.
Its on the Mk1 big nikko.
I have run a few tests and I think it may be the twin cone stripper. think its just coincidence that it has happened on two similar targets.
One thing I did notice is I need to set the scope up on the mounts with the windage turret wound in one turn.
When I went round the clock with it far right one turn down went low compared to the others.
I have had big nikkos in the past ,where you could see the ret move when the side wheel it base
And I have known mag ring to get stiff if you have use too much windage.

Yeh. Common with most scopes. They get tight when one turret is close to extreme because it has less room to move in the tube.

Are you shimming?

Could be twin cone gumming up but could well be barrel if it's an original. Short or long they can be problematic. Could try cleaning. Normally shots now and then go in one direction. There's a reason I don't have an original Steyr barrel on anymore.

[Ratinator]

No shims just rubbish grub screws .
My barrel is a Bsa but I'm in the process of fitting a mk4 on it with carbon sleeve.
16mm of steel on the front of the rifle is far too heavy.
My mk4 is going down to 13 mm with a carbon fibre sleeve , if it works the BSA will get the same treatment.
I will get the bore centred at the same time.

[RobF]

Just pick the best barrel. Don't obsess about weight, plenty of areas to lose that on the chassis.

[Ratinator]

Just pick the best barrel. Don't obsess about weight, plenty of areas to lose that on the chassis.

I'd rather carry a brick on my shoulder than an outstretched arm.
The Steyr I sold had a 15mm barrel and the weight difference was remarkable . I had no idea 1mm of steel would make so much difference .
The BSA is happy on a diet of AA pellets so I'm only getting it done if the mk4 is a success.

[RobF]

I'd rather carry a brick on my shoulder than an outstretched arm.
The Steyr I sold had a 15mm barrel and the weight difference was remarkable . I had no idea 1mm of steel would make so much difference .
The BSA is happy on a diet of AA pellets so I'm only getting it done if the mk4 is a success.

For every 100mm barrel you are saving a whole 24 grams of steel. That's hardly a brick. The double come stripper weighs about 80 from memory.

[hmangphilly]

For every 100mm barrel you are saving a whole 24 grams of steel. That's hardly a brick. The double come stripper weighs about 80 from memory.

think it was more than that mate .

about 200g for 150 mm rings a bell , i'll check later ......

[Ratinator]

For every 100mm barrel you are saving a whole 24 grams of steel. That's hardly a brick. The double come stripper weighs about 80 from memory.

think it was more than that mate .

about 200g for 150 mm rings a bell , i'll check later ......

It will be weighed before and after so I will report back on weight .
It should be the equivalent of a 3 mm tube with 16 o/d by 450mm , that will be at least 10 strippers.
The mk4 is only 14o/d so when I get the Bsa done it will be 3 X the saving.

[Brian.Samson]

It will be weighed before and after to I will report back on weight .
It should be the equivalent of a 3 mm tube with 16 o/d by 450mm , that will be at least 10 strippers.
The mk4 is only 14o/d so when I get the Bsa done it will be 3 X the saving.

Steel (depending on which alloy) weighs approximately 0.01g per cubic mm.

If you're reducing the diameter of a barrel from 16mm to 13mm - that is the equivalent of a 16mm OD tube with a wall thickness of 1.5mm (not 3mm).
The total mass of that tube ( 450mm long, 16mm OD, 13mm ID ) is 240g approximately - assuming generic Steel Alloy, or a little less for Carbon Steel.

A Carbon Fibre tube to replace the lost diameter would weigh 61g - so your overall weight saving would be 180g approximately.

You might also want to consider whether the reduction in rigidity of the barrel will have a negative impact on barrel harmonics. Barrels do vibrate when a pellet accelerates from 0 to 550 mph in a fraction of a second along their length.

[RobF]

It will be weighed before and after to I will report back on weight .
It should be the equivalent of a 3 mm tube with 16 o/d by 450mm , that will be at least 10 strippers.
The mk4 is only 14o/d so when I get the Bsa done it will be 3 X the saving.

No need, just use basic maths.

And it won't be 10 strippers

16mm tube down to 14mm is 2mm.


Calculate the difference in volume then x the density.

think it was more than that mate .

about 200g for 150 mm rings a bell , i'll check later ......

The saving...

http://www.calculatoredge.com/matwei...erial%20wt.htm

200mm 15mm solid rod = 624g

200mm 13mm solid rod = 468g

difference 156g for a 450mm 2mm solid rod

so 35g for every 100mm length... i was a bit off.

As Brian says, adding a CF tube will add about 60g meaning we're not far off the weight of a muzzle brake, which you're not sure is harming the grouping anyway... I seem to remember the muzzle brakes weighing 80, you're saving 160 without the cf tube, or 100g with it.

Cripes you'll use probably 20g of air over a shoot and a plink...

[Ratinator]

Ok I have some figures back on my new barrel mod.
14 mm barrel 519 g turned down to 12.7mm 373g then sleeved to 16mm at each end and carbon tube added 434g.
That's a saving of 85g .
That's not huge I admit but when my 16mm barrel is done that will equate to a saving of 309g which is nearly 3/4 lb ,so well worth it in my opinion.

[RobF]

A 450 mm steel barrel weighs, give or take a gram or so...

350g for 12mm

410g for 13mm

500g for 14mm

575g for 15mm

650g for 16mm

That's based upon the above calculator which uses density and volume and minusing 50g for the bore.

Gonna have to go some to get 300g off but going that thin yeh it's going to shed some.

Thought about just sawing the front end of the rifle off? After all it doesn't do anything.

[buttloaves]

Get viper connected

[lensman57]

Evening gents
I have missed a couple of targets recently at 12 o'clock and i'm thinking it may be parallax error.
I understand that its caused by not looking through the scope's center but am I looking through it high or low ?
Any help would be appreciated.
Thanks Simon

Why don't you try a Bisley scope maximiser? It will force you to put your eye at the same position everytime and it doesn't cost much. Other than that a scope like the MTC Viper connect will eliminate the parallax as it has a very short eye relief.
http://www.jsramsbottom.com/products...extension.html

A.G