Omitting cold bore shot from ES/SD calculations

[Bat Rastard]

Is omitting the 1st shot from your calculations cooking the books?
Or is it an acceptable practice?

 

[RustyInBend]

I always build 3 cold-bore shots at the start of a recording session, and do not use the numbers from them. I don't think there's a right or wrong, as long as you do it the same all the time.

 

[mgunderson]

They are your books.... you decide!

 

[CharlieNC]

It should not matter unless it is an outlier, in which you consider that impact on your shooting situation.

 

[Dimner]

It depends on the application that I'm using my data for. If I'm making target loads, I also shoot a few sighters to avoid a cold bore impacting my results. I do record my sighter info in my log book, however the data/results of my tuning groups is what I use for decision making.

If I am doing hunting load I do the same above while tuning the load. However when it comes to sighting in the final load.... a barrel cold bore is everything. In those cases, I only shoot two shot groups. First shot on a dead cold bore. 2nd imitating a follow up shot. Which means a 3 second pause. These two round groups are done with at least 20 minutes (depending on the temperature) separating the groups. My preference is to shoot these type of cold bore tests in the temperature that I will be hunting in.

 

[Webster]

Is omitting the 1st shot from your calculations cooking the books?
Or is it an acceptable practice?

If your shooting competition you only care where the shots go after a warm up shot or a sighter. For hunting a cold bore shot. There shouldn't be much difference between the 1st. and 2nd. shot. 1" groups are good for deer hunting. For varmints or deer I don't care what the ES is as long as the groups are small. They can shot 20 ES at short range competition and win. I must have a good barrel because there isn't much difference between cold bore and the next shots. I have two chronomitors and don't use either anymore. I only care about group size varmint hunting and 100 yard practice.

 

[6.5 forever]

The nice think about the Garmin Shotview app is the ability to see shots in place or hidden. Evaluating data is always beneficial.

 

[Rocketvapor]

If something really seems out of place Does it belong in the data?

 

[cranky]

If something really seems out of place Does it belong in the data?
View attachment 1541555

That is what you would use a Dixon's test to determine. Is the null hypothesis true that it is not a member of the set, or is it false and the point should be culled. Check your stats book or the NIST guide for more info on how to treat outliers. The Shapiro-Wilkes test is similar.

 

[6.5 forever]

If something really seems out of place Does it belong in the data?
View attachment 1541555

One thing for sure, I would try to find out why. Maybe junk that case

 

[Rocketvapor]

I hear that a lot.
With all the measurements available, why would you junk a case?
We can measure case properties 9 ways to Sunday.
I would want to KNOW why that case is bad.
The worst one was a cold bore shot, 2910.5fps
Think that might have something to do with it?
My cold bore shots aren't usually that bad.
That case worked fine in the first and second Primer Weight Test.
First test with a "light" primer was 2989.3, in the second test it was 3036.8 with a "heavy" primer.
I have a trip planned to see a new Great Grandson, and an eclipse.
I have the 30 cases preserved in original shot order for next practice session in a couple weeks.
Maybe that one case is worn out.
Me, I would scrap the bullet

 

[bozo699]

If your shooting competition you only care where the shots go after a warm up shot or a sighter. For hunting a cold bore shot. There shouldn't be much difference between the 1st. and 2nd. shot. 1" groups are good for deer hunting. For varmints or deer I don't care what the ES is as long as the groups are small. They can shot 20 ES at short range competition and win. I must have a good barrel because there isn't much difference between cold bore and the next shots. I have two chronomitors and don't use either anymore. I only care about group size varmint hunting and 100 yard practice.

I would be mortified if my hunting rifle shot 1” groups!…
Wayne

 

[Doom]

Is omitting the 1st shot from your calculations cooking the books?
Or is it an acceptable practice?

If the rifle conditions are not the same for the first shot (such as a clean barrel) then the data is not on the same basis as the following shots so it should not be considered. If it's the first shot out of a clean barrel in a hunting rifle and will be shot that way on a hunt then it's the most important shot.

Are you in some sort of SD/ES competition?

 

[JerkyFreak]

Have to differentiate between a cold clean bore and a cold fouled bore.

If the barrel was cleaned I would not count the first 2 shots. A cold fouled barrel should not make a difference. If it does, change the powder.

 

[6.5 forever]

I would be mortified if my hunting rifle shot 1” groups!…
Wayne

Me too. The difference between wide open country and closed in farm country...yup

 

[6.5 forever]

Have to differentiate between a cold clean bore and a cold fouled bore.

If the barrel was cleaned I would not count the first 2 shots. A cold fouled barrel should not make a difference. If it does, change the powder.

It takes about 5 shots in my backup gun to settle in. It has 1800 rounds thru the barrel.
My new barrel has 300 rounds and settles in much quicker. Like I said above, I leave all shots in Shotview so I have a evaluation history.

 

[Dimner]

I would be mortified if my hunting rifle shot 1” groups!…
Wayne

Me too. I hear one inch groups all the time. It's only acceptable for low velocity iron sight rifles. And even then I'm not happy with it.

I don't ever take shots at 400 yards. Any rifle I hunt with needs to be able to hit the heart at 400 yards on a deer. So at the very least 3" at 400 yards.

 

[Doom]

Have to differentiate between a cold clean bore and a cold fouled bore.

If the barrel was cleaned I would not count the first 2 shots. A cold fouled barrel should not make a difference. If it does, change the powder.

I didn't mean to imply those were the only conditions to consider. You are correct and there can be others. I was more in reference to what the data was to be used for.

 

[Webster]

Me too. The difference between wide open country and closed in farm country...yup

I hunted deer in PA. Most of the shots are under 100 yards.

 

[bozo699]

I hunted deer in PA. Most of the shots are under 100 yards.

Then a black powder 1” 45/70 is perfect
Wayne