Keeping gun in tune.

[Engrbill]

Tim You left out an Important Fact

All of the distinguished contributors above are doing an excellent job of explaining the practical aspects of tuning a rifle both with tuners and powder charges. They forget to mention the basic reason that changes in gun tune occur. Here in a nutshell is why: The Higgs Bosun particle is the theorized particle that transforms the energy in atoms into mass which makes the solar system, air, stainless steel, gunpowder, beer and us. It is the creator of life and as such has been nicknamed the "god particle". It is as yet undiscovered because the large hedron collider sprung a leak. Also there is a theory that for certain particles there are distant twin particles that will change if you screw with the first particle. These can be across the universe in distance but are probably closer. So if you mess with the Higgs Borun particles in your gun by twisting a tuner or changing a load you change the Higgs Bosun particles in your neighbor's gun and change their tune. Add to this the fact that merely observing a particle changes its properties.
Therefore the following is possibly true:
Your fellow benevolent shooters probably including your best friends are messing with the tune of your rifle. You are doing the same to them.
The act of adjusting a powder measure or twisting a tuner is bad enough. Don't look at them during the changing or after. That alone will change them more.
Those shooters consistently at the top of the heap do not obey the laws of particle physics. This observation has led to alternate explanations such as string, twine and rope theories.
I hope this clears up all this tuning discussion. Tim

The Higgs Bosun does not explain the Black Holes that the best shooters shoot through. Their bullets get to the target at the same time they pull the trigger and therefore do not have to travel through the atmosphere!
-----Bill

 

[upandcoming]

First of all - this was a great thread! However there is one thing I cannot get off my mind so please help me clear my head, if possible...

Gene states in this thread that 20 degrees is what will make the rifle go from in tune to completely out of tune. Wouldn't that equal the fact that 40 degree change is from one tune to another. OK? At the same time a change of 5 F is equal to halv a click (0.3 grain more or less) meaning that the distance from one tune to another is 40/5*0.3 = 2.4 gr. Am getting it all wrong?

To keep the rifle in tune throughout the day, reduce the velocity 30 fps for each five degree increase in temp. With most powders, N133 being the classic example, this equates to one half click per five degrees. For example, let's say your rifle was in tune for the first match; temp was 70. Your Culver type measure was set on 54 clicks. When temp reaches 75 the proper click value is 53.5, for 80, 53, 75, 52.5 and for 90F, 52 clicks.

Because this is also written and I cannot get this to match the above...

You can never be more than a half turn out of tune. When tuning with the powder, you can never be more than .6 grains (one number on the Culver) out of tune.

So where do I go wrong?

 

[upandcoming]

I assume this is the correct thing since? 20 degress F between the nodes?

To add to Gene's notes...

Moving two full numbers on the powder measure isn't always necessary. To follow that perscription is to chase exactly the same vibration high (or low)node in the the barrel. At +20 degrees, there is a vibration node coming up from behind that is nearly exactly where you started.

 

[Boyd Allen]

Just for grins, why don't you attempt to experimentally verify the one click/.6 per 20 degrees relationship, and come back and tell us if it holds true for you?

 

[upandcoming]

I am in the process of testing my current barrel but the info I found here was confusing for me. You refer to .6/20 F same as above, but other places it is stated that 20F is the complete distance from one node to another. I assume the difference between barrels isn't that bad? Or? When I know, sort of, what I can expect it is easier to verify that compared to rediscover? Or?

As I consider my self as a newbie in this sport any information is something I consider very valuable.

 

[russell m]

Then there are times when temp is not the key. When the humidity drops below 40% go up on the powder. Or is it that you are just keeping the charge the same. The kernels get larger as the hum. goes down so you ad more clicks to keep the weight the same
HMMMMMM. russell m