Barrel Heat Affecting Accuracy

Big JD, environmental conditions will affect your load and rifle the further you go. That affect has alot to do with the bullet you are sending and how quickly it looses velocity.

For just about any hunting situation inside 500yds, zero real world affect. The twitch you might give the rifle due to excitement is many times more affective at changing POI.

In competition, you get sighters so you adjust accordingly.

I know there are a few systems that use wind meters, barometers, palm pilots, etc to calculate the correct changes. I really don't know if they cover all the bases adequately.

My guess is they work because the expected accuracy at distance is generous enough to mask any computation error. Or the distances are short enough that environmental affects are small.

For those that shoot 1000m and further, environment will matter. Hell, shoot far enough and you need to take earth rotation and spin drift into account.

For 98% of shooters, wind is your biggest condition to watch and overcome.

With the right powders, moderate changes in ambient temp will have little to no effect on a drop chart WITHIN THE EXPECTED ACCURACY AT DISTANCE.

If you take the time and calibrate your rifle/load and support optics, first shot hits out to 1000m on MOA sized targets are readily accomplished.
Jerry
 
Thanks for the outstanding reply, I'll definately be taking notes off that. Thanks a ton!

For initial load testing (to test whether or not your rifle likes certain components), do you take all shots cold bore, with the barrel fouled?

-Rohann
 
Rohann, no but I try to keep it as cool as my patience will allow. I will bring a cooler with rags soaking in ice water to quickly cool my barrels. 'Room temp' is an ideal temp to start from. Just try and be consistent so you can judge the load not the rifle or shooter.

Jerry
 
Oh ok, thanks. So the key here isn't the difference between cold and hot, it's to do with consistency? Your method sounds sure, so I might try that as well; before I would just wait 2-3 minutes in between rounds.

Thanks a lot, you've been an enormous help.
-Rohann
 
the diference beteween my summer and winter range card is just under %MOA and 1000meters.....


Rohann I fill out the card for the target I am shooting at

I agree with Jerry wind is where it is at

I zero too a foulded cold barrel at 100meters I do all my groups shooting with a warm barrel

Just note anything you can that way it is there to fall back too


Jamie
 
So when doing load testing you do it with a warm barrel? For consistency's sake, what's a good ROF to do this with (1R/2mins?)?
I'll keep in mind to take notes on everything though. Thanks for the download too!

-Rohann
 
I didn't notice if anyone mentioned this yet, but regardless of the quality of your rifle and the physical effects of heat on the bore, I've noticed that barrel heat can and does affect accuracy simply by making it difficult to see the target.

With a hot barrel and a low-mounted scope I've sometimes found it very difficult to get a good sight picture at long range through the mirage (heat waves) coming off the barrel. I know some TR shooters use a strap on the top of the barrel to reduce this effect, but I haven't seen it being used by precision rifle shooters with scopes.
 
Shoot, eject round, check brass, check target, chamber next rd, ready, breathe, shoot, repeat.

I always to to hold rifle, trigger, cheek weld everything as much the same as the last shot.

Great tips from Jerry, Jamie and Cat!
 
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