Long Range for begginers

[liltank]

What do you mean by a Chrono? I have a range finder good out to 100 yards.

And thanks for the feedback...gun)

Chronograph. It measures the speed of the bullet. Its use is to measure your velocity and try to load in a manner that keeps the speed variation as close as possibler or what we refer to as the extreme spread in speed (velocity difference between the slowest shot and fastest shot). Example: 2600 the low, and 2610 the high. This would be an extreme spread of 10fps. Most long range guys want to keep the ES (extreme spread) 10 fps or less for consistency. To large a spread and your rifle will not group well at long range ensuring a wounded animal instead of a dead one. It's also useful for figuring out your drop tables by giving you an average speed to work with to initially get you on target. You'll find target shooters looking for the elusive 5fps or less in the ES.

 

[liltank]

The other is standard deviation or SD. If you record a 10rnd string, the SD is the average speed difference between each individual shot where the ES is an average of a whole 10 shot string.

Example:
velocity > standard deviation

1. 2606
2. >3
3. 2603
4. >6
5. 2609
6. >1
7. 2610
8. >5
9. 2605
10. >5
11. 2600
12. >8
13. 2608
14. >4
15. 2604
16. >3
17. 2601
18. >1
19. 2602

Your average for ES:2604.8fps
Your SD avg: 4fps

 

[jbjn55]

Wow... lots I didn't know about this sport. Is any chrono better than another? Preferred brand? Best place to buy?

Thanks for taking tiome to explain in such detail... much appreciated. I hope to be able to contribute soon. lightbulb

 

[liltank]

Wow... lots I didn't know about this sport. Is any chrono better than another? Preferred brand? Best place to buy?

Thanks for taking tiome to explain in such detail... much appreciated. I hope to be able to contribute soon. lightbulb

I gave you an average velocity for the string. The ES would be 10fps because the 2600 is your low and 2610 is the high. You just subtract to figure out the ES from the high and low. Anyway... Chrony's are like bullets. Everybody likes their own brand. I personally want an Ohler 35. They are the best in my mind, but they are expensive. The company called Chrony is the only one I have ever worked with on a regular basis. They seem to do ok. And some guys swear by PACT chronographs. So pick your poison and do a little research.

Tank

 

[rscott5028]

The other is standard deviation or SD. If you record a 10rnd string, the SD is the average speed difference between each individual shot where the ES is an average of a whole 10 shot string.

Example:
velocity > standard deviation

1. 2606
2. >3
3. 2603
4. >6
5. 2609
6. >1
7. 2610
8. >5
9. 2605
10. >5
11. 2600
12. >8
13. 2608
14. >4
15. 2604
16. >3
17. 2601
18. >1
19. 2602

Your average for ES:2604.8fps
Your SD avg: 4fps

Your point is well made. But, that's not the actual formula for standard deviation. Google it if you want the formula. Fortunately many chronies and Excel will calculate it for you.

The statistical significance is that with anything resembling a normal distribution (bell curve) such as MV samples... the majority will hover closer to the mean allowing you to estimate the population of future samples, 95% of which will fall within 2 standard deviations above and below the mean and 99% will fall within 3x the standard deviation from the mean.

The smaller the SD, the more tightly grouped the samples are around the mean. As such, a low standard deviation far outweighs ES as a predictor of future performance.

Sorry. I didn't mean to knit pick. But, a lot of guys fixate on ES which only takes one bad sample to throw you totally out of whack.

-- richard

 

[jbjn55]

Thanks again... I guess I'll start practicing! gun) I hope to hit something!

 

[Reelamin]

Wow... lots I didn't know about this sport. Is any chrono better than another? Preferred brand? Best place to buy?

Thanks for taking tiome to explain in such detail... much appreciated. I hope to be able to contribute soon. lightbulb

I have a Pact and a Pro Chrono. Pro Chrono is the way to go. They are the same on accuracy or at least read the same. The Pact is pretty picky about the light to give readings compared to the Pro Chrono. I like the computer on the Pact...but with todays programs available all over save your money and get a Pro Chrono.