sporter tuning

[MIKECAMERON]

Keith,

I track temp and density altitude when I test in the tunnel, but thus far I haven't been able to determine if it's a significant factor. Intuitively, I suspect temp and DA do factor in but maybe I don't have enough data and/or the effect is fairly small.
I also suspect that any effect may be more pronounced if we tested at longer distances than 50 yds/meters. Unfortunately, the non-linear increase in dispersion with increased distance for RF means the noise/scatter just about triples at 100 yds and still masks those effects. The other obvious problem, if you're a proponent of barrel compensation, is that a tune at 100 yds may not be the best tune at 50.

Whether it's right or wrong, I've found it advantageous for me to not mess with the rifle once I've determined its potential in my tunnel and know the range of scores I expect it to shoot. With the usual few exceptions the scores I've shot match fairly closely my predictions, regardless of temp/DA, unless mirage raises its ugly head as it's prone to do at some indoor venues.

Landy

Landy you need to get with BOB Collins and get his formula to use those parameters to calculate the speed of sound then you will see it is a significant factor.

 

[Bill B]

Tim and Bill,

I wouldn't disagree with anything you guys said in post #29 and post #33.
Skilled and experienced shooters are better able to make determinations of tune and estimate the potential of a rifle, but I also believe the number of shooters capable of doing this might be a fairly small segment of the RF BR community.
This can be a horribly frustrating sport if you're saddled with a poor shooting rifle and have no previous experience with the performance of great shooting rifles.

Landy

Landy, you are right this is a very frustrating sport to figure out. Some shooters spend a lot of money on a rifle and don't get the results they were expecting. Sometimes it's that there is a problem with the build, the barrel may be mediocre at best, the ammo is inconsistent, or it may be the shooter's bench set-up, technique or lack of skill at doping the wind, or maybe the shooter did something to bugger up the rifle. For a beginner shooter, this can be extremely frustrating. Last season I evaluated a rifle for another shooter who was struggling with a new build and was able to identify some of the problems. He was never going to be successful with things the way they were. I was happy to do it, cause I was in his shoes or several years. First you have to have the rifle, ammo and set-up right before you can get to the task of learning to properly dope the wind or deal with mirage.

I think the best thing a new shooter with a new rifle can do is to have an experienced, good shooter shoot the rifle and give an honest evaluation. As Tim said, some rifles are 248 rifles (or lower) and some are real hummers. A beginner can have a hummer and never know it, if everything else isn't squared away. They may never realize what they have and start messing it up. A hands-on mentor can really make the learning curve in our sport a lot shorter, especially if one is willing to listen.

 

[mks]

Kieth, Bob Collins is working on a formula that uses all those parameters and then he calculates the speed of sound for those conditions and we are seeing a direct correlation to speed of sound and how it affects tune and what change to make(on a VonAhrens tuner) as the SOS increases versus decreases, it is pretty interesting and I think it will turn out to be the key to finding a tune spot determined on the SOS.Once we get that we should be able to calculate the SOS make our adjustment then be competitive for EVERY target.This thing would probably work on a Ezell tuner as well but with a much tickier smaller adjustment because of the amount of weight moving.
MC

Mike,
Nice! Speed of sound combines the effects of temperature, pressure and density, so maybe it is the right parameter. But so do density altitude, and just plain air density. Once you have the on-target data, you could try them all. I would certainly be interested to know how it goes. Keeping my fingers crossed.

Here is a speed of sound calculator with a reference to the equations, for anyone interested:
http://www.sengpielaudio.com/calculator-airpressure.htm

Keith

 

[Wilbur]

Sporter rifle - some have sporters that will shoot well and some don't. If you're one of those that don't, and want one, you'll have to find it somewhere. Nothing will make a rifle win consistently other than the rifle itself. When you get one - don't mess with it!
__________________________________

Took a shower, got ready to go to work, and then read what I posted above. Seems a little simplistic as to what we think of our sporter rifles. My rifle will shoot 250s with a single lot of ammo. Sure, I could have spent a lot of money to find another lot but realized that it was gonna be a long row to hoe. Just seemed easier to place well in sporter and try to catch up with the big rifle. I can tell you right now that's not the way the winners think.

 

[GordonE]

Blind Testing

It seams easy to find a tuner setting, bag rest set up. If you are not shooting in a controlled enviroment.You could be spinning your wheels. When you make adjustments they may not be what they seam. Some days a 248 is a great score. The best dosen't shoot 250s all the time at every range. Different Ranges have obsticles that move a bullet more or less. Some may say in such or such condition my gun moves a bullet so far. How do they know for sure if the range has a trap house at one end or a berm some place.

When adjusting a tuner. Turn it back to original setting to see if it is worse than your new setting. Blind testing at my range with barrels and tuning has been a real eye opener for me. Testing is not always cut and dry. What people think they see is just that "Think". Conditions change all the time. Good conditions will yeald good results.
Gordon

 

[William Colbert]

Thanks for input

Thanks to all for your input.
What I have summized from your reponses is that, one needs a great sporter in order to shoot well since there really isn't much one can do to tune. Ammo plays a part, bag placement can help, weather and wind conditions (the ability to dope) are all factors that come into play in getting a sporter to shoot better. I've been told my sporter is a great rifle by many, I guess there is much to learn. A friend said, so long as you come away from these posts with some bit of information that you think will help then it was a worth while post. I have come away with many!
Merry Christmas to all,
William

 

[TangoTwo]

William,

Listen to what is said. Try it all. Keep what works for you, discard the rest. There are many ways to skin a cat. What works for me may not work for you. It takes time to learn how to shoot most sporters. That doesn't even take into account learning how to read conditions, that's a whole nother ball game.

Ken Henderson