Thread: Seating Depth Test. Waste of Time?

PS where's the next/nearest bench rest comp I can go shoot?

Originally Posted by gimp

If someone is interested to know whether seating depth, within functional bounds, makes a measurable (ie actually meaningful in practice) difference in precision for their actual use, please just go test it with a sample size that actually has a chance of somewhat representing the population (at least 20rd), and with a metric that is meaningful (mean radius) and post your results. Can't argue with data that is collected sensibly.


Likewise, if you're already convinced that it does or doesn't matter - consider - how would I test to determine if it does or does not? Better to test, get data, and make a more informed decision on your process in future - may save components and hassle in the long term

You would only have to look at nearly every Bench Rest record to see the evidence that justifies adjusting seating depth. They all do it (Bench Rest shooters), almost without exception.

So what happens if they don't?

All I'm asking is to see the actual data

Originally Posted by gimp

So what happens if they don't?

All I'm asking is to see the actual data

If they don’t, they lose to someone who does. The actual data is the target.

We must have exceptional rifles (or bullshooters) in NZ. Brian Litz recently posted up a table of average USA benchrest and F Class groups. The BR 200Y figure is a smidgen less than 0.4 MOA. Jezz just about any Tikka here will do that!

Seriously once you start looking hard at the stats and learning to understand how to utilize them, a lot of what we have been "taught" in respect to load development over the last 20 years can be shown to be complete crap.

Originally Posted by gqhoon

If they don’t, they lose to someone who does. The actual data is the target.

Shouldn't be terribly difficult to post some comparison targets between an "in tune" load vs not "in tune", at a meaningful sample size and demonstrate the difference. That's what I have yet to see

Originally Posted by Tentman

We must have exceptional rifles (or bullshooters) in NZ. Brian Litz recently posted up a table of average USA benchrest and F Class groups. The BR 200Y figure is a smidgen less than 0.4. Jezz just about any Tikka here will do that!

Seriously once you start looking hard at the stats and learning to understand how to utilize them, a lot of what we have been "taught" in respect to load development over the last 20 years can be shown to be complete crap.

The 200 yard LV record is 0.091”. HV is 0.109”. Those groups are 5-shot groups.

Records are by nature outliers. Outliers occur in any population. What makes us confident that our process for sampling that population gives a prize to an accurate representation of the population vs a prize to whomever gets the best random outlier on the day?

Originally Posted by gimp

Shouldn't be terribly difficult to post some comparison targets between an "in tune" load vs not "in tune", at a meaningful sample size and demonstrate the difference. That's what I have yet to see

5 different matches shot through the course of the day, as environmental conditions vary and then those scores averaged to give an ‘Agg’ is a pretty good sample size. Repeat that for 2 different ranges for a Grand Agg or for 3 different rifles for a multi-gun Grand Agg and you should be satisfied.

Originally Posted by gimp

So what happens if they don't?

All I'm asking is to see the actual data

I have no Data to supply.
I’m surprisingly actually veering into your line of thinking.
Butttt……
If you think those “ Hall of Fame “ Benchrest shooters haven’t done a “ Shit Load “ more testing than you , well I’m sorry we do now come to a crossroads in this conversation.
Those guys talk in thousands of an inch being the different between winning and going home with nothing .
They make their own projectiles , use the best of the best barrels , chamber their own barrels , test in tunnels , weigh cases / primers / projectiles , fine tune the ignition systems of their rifles etc etc etc .
Lets make sure the apples we are comparing are actually apples.
There is hunting loading/accuracy and Benchrest / loading accuracy .
The reason I’ve been veered down your path of thinking, is because we are dealing with Factory/semi custom Rifles that no matter how much we want to be , aren’t actually that good compared to what the real experts run .
Mate I’m with you on most of what your talking about , but ignoring the vast resources of those Benchrest guys shouldn’t be so easily considered.
It doesn’t matter what the reasons are why they are the most accurate Riflemen in the world , butttt… they are the most accurate Riflemen in the world .
Personally if they gave me some advice “ I’d listen “ .
In a Hunting/ Load scenario I’m all onboard with what basically is the latest Hornady philosophy.
If I was wanting to win a Benchrest match either local or World championship, I’d be seriously listening to the guys who have won it before.

Originally Posted by gqhoon

5 different matches shot through the course of the day, as environmental conditions vary and then those scores averaged to give an ‘Agg’ is a pretty good sample size. Repeat that for 2 different ranges for a Grand Agg or for 3 different rifles for a multi-gun Grand Agg and you should be satisfied.

To my mind all that proves is they have a very precise rifle and they can shoot it accurately.

What we need to see is at least 20 shot groups (preferably 50 shot) at an optimum seating depth and another string at a sub optimum depth and be able to statistically observe a difference, further more the test needs to be repeatable.

Originally Posted by 7mm tragic

To my mind all that proves is they have a very precise rifle and they can shoot it accurately.

What we need to see is at least 20 shot groups (preferably 50 shot) at an optimum seating depth and another string at a sub optimum depth and be able to statistically observe a difference, further more the test needs to be repeatable.

I have a better idea, why not buy 5 spare barrels. Lets say 1500 shots before barrel is burnt out, fire 1499 rounds through each barrel to confirm group then save last shot for hunting before barrel is burnt out

Originally Posted by Ground Control

If I was wanting to win a Benchrest match either local or World championship, I’d be seriously listening to the guys who have won it before.

If I wanted to learn better breathing, wind calls and trigger control I'd seriosly listen to what they have to say.

I'm skeptical to believe that seating depth has much to do with it rather than the overall utmost care for every aspect of a handload. F class shooting is so deep into the weeds of trying to squeeze out minute gains that beyond being a skilled shooter with a quality rifle, fiddling with loads is just a hobby with diminishing returns.

Back on subject though.
It still remains as fact, and has been proven time and again, that most of the testing done in regard to hand loading is done with group sizes that are functionally too small to mean anything. A sample size of three is meaningless. A sample size of five is barely large enough to show the accuracy of a load. Repeated sample sizes of five collated together? That's just averaging small sample sizes.

Bigger sample sizes, bigger groups, confirm two things: We are wasting our time tinkering and probably don't shoot as accurately as we think. Either a rifle and load shoots accurately or it doesn't. Change the powder, change the bullet, or find your accuracy problems elsewhere.

Originally Posted by gimp

If someone is interested to know whether seating depth, within functional bounds, makes a measurable (ie actually meaningful in practice) difference in precision for their actual use, please just go test it with a sample size that actually has a chance of somewhat representing the population (at least 20rd), and with a metric that is meaningful (mean radius) and post your results. Can't argue with data that is collected sensibly.


Likewise, if you're already convinced that it does or doesn't matter - consider - how would I test to determine if it does or does not? Better to test, get data, and make a more informed decision on your process in future - may save components and hassle in the long term

You can believe whatever you like, I don't need to convince you that seating depth matters, but with an ACCURATE rifle I believe what the bullets tell me on the target and since I have seen the effects of seating depth changes and can go from large groups to small groups just by changing seating depth and back to large groups by changing seating depth back to where it was.
In the link I posted above go to 1.10.19 and listen to Speedy's comments, he is a Hall of Fame Benchrest shooter and a great gunsmith.

Now just to give some examples of aggregates take a look here
https://www.nbrsa.org/disciplines/sh...world-records/
if you look at the aggs, not the groups, you will find some that have a total of 8 x 10 shot groups at 100, and 8 x 10 shot groups at 100 & 200 (160 shots for the agg) that are sub 0.250"

But as you say a record is where everything has come together, barrel, bullet, reading the condition, tune etc
If you look at multiple Benchrest match results you will see some trends, even when it was real windy at the match.

One thing I will say if you are wanting people to shoot groups with a large number of shots with hunting barrels how will the hot barrel affect group size?
Most hunters who are shooting animals don't shoot enough shots to get their barrel hot, and in reality, it is the first 1-2 shots out of the barrel that matter

Originally Posted by gimp

PS where's the next/nearest bench rest comp I can go shoot?

The next Benchrest match that I know about is in Nelson on the Maitai range over Labour weekend.
I've sent you a pm with who to contact about participating.