Chronographing loads

MagnumManiac

Well-Known Member
Joined
Feb 25, 2008
Messages
3,150
I take my chrony data at a minimum of 10 shots and a minimum of 10 outings in different days and locations.
This is all input into my app and I get good data from this. Just like using a chrony over an entire match, good data that shows how good your load really is.
A 5 shot string tells you very little, a 10 shot string isn’t much better statistically, but is better.
40 shot strings tell you what you need to know, especially the average velocity and ES. SD is not really important to me.

Cheers.
 

lancetkenyon

Well-Known Member
Joined
Jun 3, 2013
Messages
3,507
Location
Arizona
Almost every time I take my rifles out (except for hunting), I shoot them over a chronograph, and record the speeds. So I have rifles with 500-2000+ rounds of recorded speeds. Pretty good to know what your loads do in all conditions. From 20° to 115°+. Tells you your true ES when you have a sampling of 100+ recorded shots.
 

Starlite

Well-Known Member
Joined
Dec 8, 2019
Messages
576
Location
New Brunswick Canada
I take my chrony data at a minimum of 10 shots and a minimum of 10 outings in different days and locations.
This is all input into my app and I get good data from this. Just like using a chrony over an entire match, good data that shows how good your load really is.
A 5 shot string tells you very little, a 10 shot string isn’t much better statistically, but is better.
40 shot strings tell you what you need to know, especially the average velocity and ES. SD is not really important to me.

Cheers.
For me and my BR shooting SD is very important. Also I mark all flyers (true ones not trying to convince yourself otherwise)
For the purposes of LRH SD is not that important but Coldbore needs to impact where I’m aiming. When I ladder test I test in pairs at 600. Afterwards I’ll shoot 40-60shots of a previous test. Then I know if I’ve got something.
 

MagnumManiac

Well-Known Member
Joined
Feb 25, 2008
Messages
3,150
If any of my rifles walk POI due to cold bore variation, they either get a love job done to them, or they get sent down the road.
SD is important, just not what I focus on when I’m shooting strings of 10 shots. It only becomes a focus for me over many hundreds of rounds recorded.
I have shot exceptional groups with loads that were running 100fps ES and SD in the 40’s, the Bullets didn’t know that and went into tiny little groups at 300mtrs. I didn’t know this either until I chrono’d the load.
I let the groups tell me a thing or two before I chrony them, but at a practise day, when chrony’s are allowed here, I record every shot, even sighters.

Cheers.
 

Tiny Tim

Well-Known Member
Joined
Jan 26, 2015
Messages
913
Cold bore mapping to me is just as important in determining ES and SD Especially if your a hunter. You want that confidence that the first shot, which is the most important to go where you expect it to. Just my opinion.
If you chrono all your cold bore shots, it might be interesting to see the ES/SD numbers for that data set.
 

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