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What if.... A remedy for the "cold shot".

 
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  #22  
Old 05-17-2014, 08:56 AM
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Join Date: May 2013
Location: Elkhorn Idaho
Posts: 358
Re: What if.... A remedy for the "cold shot".

Over the course or the last 85 years there has been allot of time and money invested into understanding the effects of a cold bore/warm bore shot. This was done by PHD,s with the billions of government military dollars and by sparks of tinkerers with there thoughts that try to expand the spark into a forest fire, just to end up with a small part of knowledge that was figured out many years ago. Unfortunately they loose a lot of personal time and sometimes money.
I will try to in a very short form explain what is happening in the barrel.
When a shell is discharged in the barrel the heat off the burned powder starts to heat the apex of all the rough edges in the barrel. Lapping and polishing helps this but all metal being porous is going to be rough to some degree. The heat that instantly is induced into the rough edges then dissipates into the denser metal of the rifling and then into the main body of the barrel. Metal is a conductor of energy. Since no metal is perfectly uniform in density the barrel expands and contracts at different rates causing non uniform expanding and contracting of the barrel. Think of it as stretching and pulling through out the length and circumference of barrel. The result,,,stress in the metal and the barrel/rifling not being perfectly true. Something we definitely do not want for accuracy!

Now not to break the benchrest world on their myths. Cooling the exterior of the barrel does nothing! The interior of the barrel is still a different temp. The barrel has to cool completely from shot to shot to have a somewhat true barrel.

Fluting helps the barrel cool better and in theory could make shot to shot placement a little better but in truth the quality of the barrel steel if much more important.

straight fluting can actually degrade the performance of a barrel. inducing stress on the rifling do to non uniform metal thickness and cooling around the riflling. This is such a small factor because the rifling itself causes this.

Er Shaw patented the spiral fluting around this concept in correspondence to the twist of rifling and matched it to the rifling due to this.

These are so small of changes that most can not see it. Even the very best of all gunsmiths. There is many things that hide the true accuracy of what a barrel could be.

1. Technology has already surpassed the ability of what a human can shoot with the eye sight that God has given us, the heart pulse in our finger, the temp of the air varying across 1000 yds, wind etc.

2. Barrel steel has advanced so far the density and strength is so much better than it was even twenty years ago. This has reduced much of the stress that we are talking about.

3. A barrelmakers ability to build quality and a gunsmiths ability to deliver upon that quality if far more important to accuracy to anything that we have discussed here

as a ending comment the military actually studied this in depth on the water cooled machine guns. They came to the same conclusion as the high priced PHDs.

The most successful of the tinkerers were Christensen Arms and Proof Research in absorbing stress and harmonics within the carbon fiber. I don't think they even understood this, they never marketed it as so. Unfortunately the wrap creates other issues and does not solve the problem. George Vais ( Vais muzzle break fame) was trying to develop a "Barrel Stretcher" to cure the problem and it never caught on.
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  #23  
Old 05-17-2014, 09:15 AM
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Join Date: Oct 2007
Posts: 880
Re: What if.... A remedy for the "cold shot".

Quote:
Originally Posted by Derek M. View Post
Well you have made it quite obvious you don't have a fundamental understanding of what fireworks is getting at and my best guess is you have failed to read this from him:



The poster is talking about heating up the tube for a first shot in the field. And I said exactly what I meant so reread it cautiously before I point out you being wrong again and again.
Then I will revert to my origonal statement......if my (fouled) gun didn't shoot the same place from first shot to , say third, or fifth shot it would be a tomato stake or FF tube. The only thing that affects my fist shot is if the bore has been cleaned. Now...if you are talking 15 -20 rapid shots ...ie, a HOT tube vs a cold one..then yes , you will get verticle simply by the velocity change from the entire bbl swelling. You will get a little faster. But we are talking hunting situations here, not br/fclass, and not load development. Things in the hunting world should NEVER get that hot. I have shot MANY five shot GROUPS at my 1200 yard target (I have my own range) starting with a cold bore. The targets are the same as one fired with a warm bore. I see no evedence of that little amount of heat affecting anything. I color my bullets and activly look for any stringing..I know which is my first and my 5th shot. Now, that being said I still find myself ..once in a while...waiting 30 min between shots to conferm my final zero. I think it's a recessive gene popping out now and then.

Now, a poor factory tube, or a poorly relieved custom (which is very rare).. ..whole nother deal. But this is LR hunting We best be using the best and correct any issues.

Wind....as far as the OP and title of the thread....we are talking FIRST SHOT...which, to the best of my knowlege, means cold bore. xx degrees is xx degrees weather the wind is blowing or not. True, once you warm things up the wind will help cool things down faster. Also, if you zeroing your rifle at 80 degrees above and then expect it to perform at -10 without first checking zero... I mean...come on....really?? I can see a 20 - 40 degree difference..we see that from day to day up here, but come on..90 to 100 degrees.

You want to make things truly equal.....keep YOUR AMMO TEMPS the same...say , body temp. The differnce between hot and cold ammo is definatly a reality. Try shoot rounds that have been baked in the sun in the same group as ones right out of the cooler................................... But, that is a whole nother topic.
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