Scatter Node Test?

[jelenko]

This is exactly a negative test case.

OK. But, it's a degenerative example. The rifle/ammo system is always going to produce scatter nodes with the same load.

What's the point of stuffing more data into the same results?

 

[Bronsin]

I have used larger groups that usually consisted of an unoptimized powder charge to evaluate bullets since better bullets will always shoot better, and primers to see if one brand will work better or not with my chosen powder, and got some encouraging results going forward. There are times when the difference in a new variable is so small that it's hard to determine if you made a meaningful change when the groups are already tiny to begin with. A larger group can show changes more easily.

I can't however see the utility in firing large groups just for the sake of it. There's nothing to be learned by shooting a load that won't hit the point of aim, or respond to corrections in wind intensity.

 

[Keith Glasscock]

Nope. You're wrong. I deal with happy and unhappy paths daily. This is exactly a negative test case. It is the "Unhappy Path", where I am verifying I get an error when I use invalid inputs.

Happy path testing: good load test, small sample size results in good results in a 20 shot string at distance in good conditions

Then there is the unhappy path: scatter found with OCW, small sample size results in bad results at distance in good conditions
IE:
•bad inputs: scatter load
•error: bad group at distance
•expected result: bad inputs should throw an error

Negative Test:
Test Requirements: bad load shot at distance
Result must be: bad group
If you get a good group, your negative test failed



That is an interesting strategy, to practice with a bad load to make sure you can deal with that situation when it happens...which will inevitably happen.

How big a variance have you found between your good node and scatter node when you do this? Your response was exactly what I was curious about.

This is F-Open findings and do not likely apply to other disciplines like Benchrest

At mid-range, it'll still clean the target reasonably easily with a significantly reduced X-count.

At long range, my rifle will shoot 197-198 easily, and I can squeak a 200 out on occasion, but the X-count is really low. It is definitely more of a challenge for the driver... It's not as point and click as an in-tune rifle is.

There are a lot of factors that play into the outcome. Not least of which is rifle design. How far "out" you can get is as important as how "tight" you can get the rifle when you look at the entire lifecycle. To me, it isn't a top-fuel funnycar where you either win or blow up... It's more of a sporty daily driver.

 

[Sandstorm]

No matter how I try.. .this just makes my head hurt...
Ill pass.....

 

[jelenko]

This is F-Open findings and do not likely apply to other disciplines like Benchrest

At mid-range, it'll still clean the target reasonably easily with a significantly reduced X-count.

At long range, my rifle will shoot 197-198 easily, and I can squeak a 200 out on occasion, but the X-count is really low. It is definitely more of a challenge for the driver... It's not as point and click as an in-tune rifle is.

There are a lot of factors that play into the outcome. Not least of which is rifle design. How far "out" you can get is as important as how "tight" you can get the rifle when you look at the entire lifecycle. To me, it isn't a top-fuel funnycar where you either win or blow up... It's more of a sporty daily driver.

Wait. You mean that essentially any powder charge/bullet will produce < 1 MOA? [no wind].

 

[Keith Glasscock]

Wait. You mean that essentially any powder charge/bullet will produce < 1 MOA? [no wind].

In a rifle designed properly, any powder charge will. Bullets are a different question. Get the wrong one and no powder charge will produce <1MOA.

 

[Webster]

Practice doesn't make perfect, perfect practice makes perfect. Shooting your worst group doesn't tell you a group is best. Shooting 4 or 5 best groups tells you whats best. Please explain to me shooting with the intention of making a back group tells you anything?

Many of the guys asking questions about nodes have probably never shot competitive groups and never will. Tony Boyer quit giving BR lessons. He got tired of telling people their rifle couldn't be competitive. It's like shooting pool after 6-12 months you know if you have any real skills. Practice won't help 95% of the competitors.

 

[ebb]

I don't see how intentionally load your worst came help at all, if i am going to shoot getting a smaller group is the direction am going.

 

[Doom]

I’ve worked with OCW for over ten years and we do look for the “scatter” node but it is to confirm a OCW node in some instances. There are rifles that do not show a discernible scatter node at 100yds. This are also times when an apparent OCW node will show up at 1.5% above a node which is where you expect a scatter node to be.

Looking for a scatter node straight out of the chute that may or may not be detectable would be a waste of components.

 

[Webster]

I'm assuming when going to a match, everyone uses the good node from their load development. And from that, you gather data.

Has anyone ever done negative testing where they take their scatter node and see how it groups for say a 20 shot string to compare it to the good node?

[When I get time I'm gonna try this]

Groups only get bigger with more shots. A waste of ammo and and barrel life. I have never looked for what might be called a node. Small round groups.