# long range shooting factors



## full_bore1000 (Mar 14, 2009)

I was recently shooting a friends 308w at 700 yds and we were talking about all the factors needed to take into account to make a "competitive rifle",one thing he talked about that I didnt quete understand was "jump".As the projectile passes through the barrel a vibration is sent up the barrel making it move up+down+left+right just a fraction,he said his 308 was at 30 000 and he has fine tuned it to do 8000 or a lot less vibration and therefor more accurate at longer ranges,If anyone can shed a little light on this for me and explain barrel jump,how to measure it and how to get the ideal amount would be greatly appreciated,keep in mind I have a 7mm Rem Mag and shoot it to 1000yds,Thankyou,Ryan.


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## gunattic (Jan 9, 2005)

this link may help explain things:
http://www.rifle-accuracy.com/harmonics.htm


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## full_bore1000 (Mar 14, 2009)

Thankyou for your reply, It was most interesting and educational


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## The Norseman (Jan 8, 2005)

Thank you so much for posting that.

When I talk to friends interested in starting to reload, I always get
on the subject of how reloading is basically changing the harmonics
of the barrel to get accurate loads.

Thanks again, great article.


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## NDTerminator (Aug 20, 2003)

The reason virtually all precision rifles have heavy barrels is that the mass/stiffness dampen ocillation and don't heat up as quickly as sporter weight barrels. This promotes a consistent level of accuracy.

That's not to say the sporterweight may not be as accurate, but it probably isn't going to be able to produce the same level of repeated & consistent accuracy.

I have a Tikka T3 243 and a Remington 700 22-250 with sporter weight barrels that will match the accuracy of my Remington 700 308 work rifle,
but I have to let the lighter weight barrels cool after a couple shots to repeat it....


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## Aznative (Apr 6, 2009)

Check out Dan Newberry's site:

http://optimalchargeweight.embarqspace.com/


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## full_bore1000 (Mar 14, 2009)

Thankyou for all the feedback and links its helped a lot in understanding the harmonics of a barrel but I just dont understand how the vibration is measured and converted into numbers,any help will be appreciated,Ryan


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## laxratnd (Jan 23, 2008)

What you are talking about is barrel harmonics. The thinner the barrel is the more harmonic vibration you will have which usually results in less accuracy. The thicker your barrel is the less harmonic vibration you will have which results in more accurate rifle. I myself like larger contour barrels and short barrels for instance a 20in is great for a .308. Being short and a large contour lets it be more rigid.

The only real way i know how to measure barrel harmonics is to shoot the rifle using super high speed cameras and videos. This equipment is made to be able to see the vibration in the barrel as the round goes through the barrel. This is probably the best way to test it out to see what you barrel is actually doing and how to improve it. The less vibration equals more consistent shots.

lax


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## full_bore1000 (Mar 14, 2009)

like this??


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## laxratnd (Jan 23, 2008)

yes that is the general concept of it, but these guys have certain charts they put up so they can see how much movement and so on.

Just remember that is not the only thing that has factors in long range shooting.

You have things as the shooter, weather and rifle bullet combo.

For example you have breathing, trigger control, sight alignment, natural point of aim, cheek pressure, hand pressure.

then you have stuff like, wind, humidity, sun, cloud cover, mirage,

Then you have your rifle and if you have it tuned to a certain load, type of stock, is it bedded.

We can go on and on about long range factors but thats the basic.

Just dont forget your good old practice, this is your best way of getting rid of as many factors as you can be learning and practicing.

good luck
and shoot tens.

lax


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## full_bore1000 (Mar 14, 2009)

Thanx I understand their are a lot a factors this was just 1 that I couldnt put my finger on,Im just reading another interesting article on it now,see what you think http://www.ozfclass.com/articles/1/psm_2005_03.html
Thanx again,Ryan


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## xdeano (Jan 14, 2005)

> "A thought. If the increased accuracy produced by a barrel tuner were only due to it being a weight attached to the muzzle, then why would it need to be adjustable? In other words, if all a weight attached to the muzzle did, was to slow down the rate of the muzzle oscillations, or decrease the severity of them, then the weight would not need to be adjustable. But the weight, in and of itself, is not what causes a barrel tuner to increase accuracy. No, it's being able to adjust the weight of the tuner very accurately, so it will position the tuner weight at exactly the correct spot to fool the barrel into moving its node, or parallel dead spot, to the exact exit of the crown."
> (http://www.ozfclass.com/articles/1/psm_2005_03.html).


So how would a suppressor affect this then? I'm guess it would also act like a weight attached to the muzzle. It would definitely affect the barrels harmonics, pulling that dead spot right to the muzzle. I'll have to ask a few of the suppressor manufactures this question also.

Very interesting read.

Thanks
Deano


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## full_bore1000 (Mar 14, 2009)

Ive read a Suppressor will effect the accuracy of a firearm and one would presume due to the change in the dead node I guess you would have to find the right round to suit whilst using a suppressor,best of luck


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## Plainsman (Jul 30, 2003)

Since the barrel tuner doesn't have to move far to have a significant impact you would think that a suppressor could be tuned by moving it back and fourth and locking in place with a lock nut. It's going to weigh a lot more, so would it have to move less for the same impact as compared to a tuner. Or is it so heavy that tuning is out of the question?

Darn Deano now I have to get a license and a suppressor. I was looking at this place in Texas that has a 308 with suppressor for $2100 and they guarantee under 1/2 inch groups.


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