Long Range Tuning

[Terry]

This is for long range 600-1,000 yards.

Once you have developed your load. Do you change it during a match? If so, what do you change, buy how much, and why? How are you determining when to change? By shots on a target, which often come too late to use? By change in the weather conditions.

This is mostly for benchrest but may apply to F-Class.

 

[ttfreestyle]

Yes I NEED this instruction manual as well!!

 

[Rick300]

Me too!!

 

[mikeeg02]

I think you're going to find you need to "learn" your/a cartridge and do a little testing. Depending on what powder you are using, you should be able to see approximately how many fps a grain of powder adds (or a tenth rather), and per 10* ambient temperature changes how much velocity it adds or subtracts. Then you will need to look at your target to see if it starts to print more vertical one way or the other.

Start by documenting temperature when you shoot a target(right on it is best for later reference) and look for the difference in varying temperatures and humidity if you can measure it. Youll also need to compare your target to others to make sure you arent reading into a condition, rather then a load issue. Shooting in a match is best for this, because the mental conditions are the same, and you have other targets shot at the same time to verify you didnt get caught in a condition. It takes time, some documentation, and then testing.

You can do it yourself by shooting early morning, then later in the afternoon, or in 10* or so increments. The problem with doing it on your own, is if you didnt see a condition happen, you may have something that prints on your target that could point you the wrong way, and it wasnt the loads fault, but the conditions.

Edit: I apologize that this got kind of long, and is somewhat vague, but different powders, different cases, unfortunately there is no easy way.

 

[Terry]

Mike

Thanks

I get the powder changes, but not the seating depth others speak of.

 

[mikeeg02]

I think the seating is rather as the thoat wears. At least in my limited experience. I suppose sometimes you could change seating in the field when you realize you will be out of your tune while at a match with an arbor press and have a similar experience. (In hotter conditions then expected) Unless you needed to seat them longer, as thats a little tougher. But again, that kinda of depends on where you normally seat the bullet anyways.

If you were say .005 off, and in tune at 60*, at ~85* you may find its a little hot, and seating a little deeper in puts you back in tune. But you would want to test that first.

I think most BR shooters like to set the die and forget it. And vary powder for expected conditions.

 

[dmoran]

Terry,
The ways I've seen it done for 1000-BR, and have done myself, when adjusting seating/powder/tuner were based on testing from the practice days, and/or the evenings after a match for the next days match. And of course from notes based on testing at home (like Mike alludes).

 

[Terry]

Mike and Donovan

Thanks

That was my experience.

In another thread others spoke of changes in seating depth due to changes in the weather conditions. I have no experience in that.

 

[mikeeg02]

Mike and DonovanIn another thread others spoke of changes in seating depth due to changes in the weather conditions. I have no experience in that.

I think in that instance they had a load ready for let say 65* as the weather man told them it was to be overcast, and the sun came out and it was 80*. Or something to that magnitude. Though the short range BR guys are reeeaaallllllyyyy good at making little holes. Its a tough crowd to be competitive in.

 

[Alex Wheeler]

The last year I competed I shot a different load each day. We dont have the chance to load between targets with our format. I adjusted powder. The way I develop a load lets me see what groups look like on each side of the tune so you can tell if you broke out the top or bottom, and the weather changes make it obvious which way you need to go as well. How much was just a gut thing and crossed fingers that the next day would be close to my guess. Sometimes you get burned, but you can try to save it with changing the temperature of your cartridges. I chased the lands, measuring every time I loaded ammo. Usually when a guy is changing his seating depth its because the gun shot really bad and its a hail marry attempt because your already screwed and its all you have time to do between relays.

 

[Puzzaz01]

Maybe I've just been really lucky but my seating depths stay the same for about 800-1000 rounds and I only adjust my powder charges the night before a tournament according to my guess as to what the temperature will be. I do check my lands for erosion but I can't find any changes until late in the barrel life. I do not run my rounds hot, I tune for consistantsy.

Darrin

 

[savagedasher]

I haven’t changed my tune in over a year
I use the Same primers same lot of powder same bullets
And I tune at 100
But I also am using the Same
cases
First I fire the cases then check the internet volume
We don’t have a large swing in temperature .
I then put the tuner where I’m going to start
I then shoot through a crony
Changeing seating depth
I find the flat spot in speed
Normally it will give a window of 5 to 8 thousand
Then it’s time to tune
I tune of the point of aim at 100
You going to find two tunes A up and a down tune . If you tuner work that
fine .
You have eliminated much of the vertical with seating depth and case capacity . Your load shouldn’t change till the throat erosion take you out of the sweet spot .
After you have worked with a tuner you can adjust both vertical and horizontal .
But that takes practice and s tuner that has fine adjustments

 

[dmoran]

I haven’t changed my tune in over a year.....

How did this method of tuning prove out for you at matches over the year ?
What all matches did you shoot / use it at ?

 

[Colnagotex]

I used the exact same load all year long on my 308 FTR rifle shooting at 50ft above sea level and everywhere in between 6000ft in Raton. I did measure my seating depth to make sure my erosion was in check, but that was it. My barrel was new at the beginning of the year and it has 2500 rds on it today, so maybe i just got lucky with my barrel but it's still shooting great.

 

[Northridge]

all my decisions are decided pre match day, I'm either ready by that point or not. what I will do in a sighter period if rifle is not performing like it typically does, I have adjusted how soon or late I pick up the rifle with my shoulder or how much static shoulder pressure I implement before each shot is sent. its surprising how well this will work in a pinch.


Shawn Williams

 

[dcali]

F class is a little different. The matches are not conducive to changing things up on match day. I think most of us keep an eye on things as the season goes on, and maybe make a range trip to retune if things are getting sloppy. It’s not like benchrest where being a little out of tune keeps you out of the running.