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#1
05-14-2009, 05:11 PM
 JEREMY logan Posts: n/a

My new barell is almost broke in so now i'm going to start the chronograph process . What kind of numbers do i need to see as far as standard deviation and extreme spread to know i'm were i need to be for an extremely accurate load for 1000 yrds and further tell me the way you do this i'm all ears (sorry for the spelling and typing errors)
#2
05-14-2009, 10:16 PM
 Silver Member Join Date: Oct 2008 Location: Bryan, Tx Posts: 284

SD less than 10 is excellent ammo. This is the shape of your bell curve. ES is a measure of have much "range" is in your velocity which is equally important. To know what ES is significant, plug varying ranges of velocity into your ballistics program to know what type of ES you need to stay in the 10 ring at 1000 yards. ES can be misleading because 1 high value in your string of ten can give a false impression of increased ES.
#3
05-15-2009, 10:06 AM
 JEREMY logan Posts: n/a

Quote:
 Originally Posted by nheninge sd less than 10 is excellent ammo. This is the shape of your bell curve. Es is a measure of have much "range" is in your velocity which is equally important. To know what es is significant, plug varying ranges of velocity into your ballistics program to know what type of es you need to stay in the 10 ring at 1000 yards. Es can be misleading because 1 high value in your string of ten can give a false impression of increased es.
Thanks for the info. I'm still a little confused I have the nightforce for a ppc. I had intended on letting the paper tell me when I have a good load say if i'm grouping very well @ 300 yrds I would think that load would perform well @ say 1000 yrds. I have read in the past (can't remember were ) that you need a good SD and ES on your chronoy inorder to shoot well @ extended ranges so my question is if my load shows to be good @ 300 or 400 yrds would it mean my SD and ES is right were it needs to be? I might not be able to shoot consistently inside of the 10 ring (but) when I pull the trigger I want a load that can.
#4
05-15-2009, 02:21 PM
 Platinum Member Join Date: Feb 2008 Location: Wampum, PA Posts: 1,456

Quote:
 Originally Posted by JEREMY logan I have read in the past (can't remember were ) that you need a good SD and ES on your chronoy inorder to shoot well @ extended ranges so my question is if my load shows to be good @ 300 or 400 yrds would it mean my SD and ES is right were it needs to be?

Jeremy- I had/have a couple really good mentors I communicated with on this board when I started loading for long range. Hopefully one of these guys will catch this thread. They both told me I needed an SD of 6fps or better. You can have an ES in the low teens and still achieve an SD of 6fps.

You can shoot good groups at 400 and not have good speeds. You can also have the opposite. Work up a load at close range with good #s then test it further down range would be my advise. It wasn't easy and it took along time for me but I'm much better off now for it.

I would also recommend shooting your charges in 3s. If your new to this the "ladder method" is likely going to provide confusing results down the line. Use your chronograph and shoot 3 shots, then step up the charge, 3 shots, step up the charge. This takes longer than the short cut methods but it leaves less for interpretation. I did a lot of tail chasing because I tried short cut methods. It may work OK for others but if your experience level is like mine was at the time it won't for you. Skip the short cuts learn to interpret your results and then you will recognize where you can use a short cut to your advantage. There is no advantage if you misinterpret your findings, there's just "back to the drawing board".

Again I'll quote the wise man from Idaho that said "There are no free lunches".

Good luck and don't relent on you questions.
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Last edited by jmason; 05-15-2009 at 02:31 PM..
#5
05-15-2009, 02:25 PM
 Platinum Member Join Date: Mar 2007 Location: MN Posts: 1,218

I am not certain about the ES and ED. However, I'm pretty sure that if you have a good load that shoots well at 300 yards, you MOST LIKELY have a load with pretty consistent velocity. But, there is a Big difference between 400 and 1000 yards. Simply looking at a ballistic program and shift your velocity a few fps will tell you how much. So, from what I know, you need to not only have a load that shoots well, but you need to verify that it has a very very consistent velocity to boot.
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#6
05-15-2009, 02:32 PM
 JEREMY logan Posts: n/a

Thanks jmason thats the post i was looking for i want stop until the numbers are right ..who ever said it could be done overnight now if i could just get the wind to stop blowing it's been that way all month .
#7
05-15-2009, 03:07 PM
 Silver Member Join Date: Oct 2008 Location: Bryan, Tx Posts: 284

A lot of the BR shooters brag about single digit ES and SD. Having these types of numers in a ten shot string is truly amazing. The goal is consistency and so the closer the better! These numbers may not be possible/practical if your goal is to knock a deer down at 1000 yards. Work up your loads as mason suggests. Good advice. Remember, ES and SD are "statistical calculations" and should be measured in 10 shot strings. Shooting 3 shots and saying you have great ES and SD is a poor statistical analysis of your data.

You have to shoot loads at all ranges intended. A lot of external ballistics come into play at longer ranges that may not show up at shorter distances

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