Thread: Variables affecting precision

Good to see some interest in the discussion and hearing some different points raised. I'm keen to hear others opinions.

I think my primary interest in this instance, is in how the information is communicated, or utility of the model, more so than the accuracy (precision!) of the model (which is obviously important).

I think that new players in the reloading space especially, are required to wade through a lot of information that often competes and conflicts at times. Maybe there is a better way to communicate the important stuff?

Personally, I spent a lot of time enamored with the OCW method of load development; however after learning more, I see that the variables I was manipulating were unlikely to be having the effect I thought they were. Not to say I didn't develop a good load, but that I probably wasted components unnecessarily for an outcome that I could have likely achieved by picking a random charge weight (RCW method?).

If I recall correctly, one of the famous Greek philosophers described wisdom as being able to see through the bullshit, to the true patterns of reality. Similarly with reloading, I think we want to be identifying the 'true' patterns, and not be fooled by the three-shot groups so to speak.

All this to say, like more learned folk have already suggested - a good platform, combined with a powder and projectile combo that plays nice, some decent fundamentals, and you're likely 90% (or more) of the way sorted.

Originally Posted by zeropak

I think the firearm part of this accuracy equation is a separate issue, as in separate to the ammuntion factors. overall precision shooting (the ability to deliver a projectile to the intended target, or the ability to delivery multiple projectiles to the same given point) can be broken down into.
1: External influences, such as wind, mirage, etc
2: Shooter ability
3: The firearms accuracy potential
4: The ammunition
In the diagram above the firearm and the ammunition are lumped together. Would it not be better to take the delivery system, the firearm, out of this and treat it separately.

Yes good points. I probably could have labeled it better. I was thinking more about reloading specifically, i.e. those things that we tend to play with, rather than all factors affecting precision.

I used the circle (shooter related factors) to lump a lot of stuff together, which I guess could include environmentals. I wanted to try show how any of the variables on the pyramid will be constrained by this. I guess if i was going to make a flow chart, I might say something like - step 1 - "establish baseline accuracy of platform and shooter", before progressing to playing with any reloading stuff.

Perhaps you need two pyramid s.
1 for rifle, 1 for shooter and environmental

Originally Posted by earplay

Good to see some interest in the discussion and hearing some different points raised. I'm keen to hear others opinions.

I think my primary interest in this instance, is in how the information is communicated, or utility of the model, more so than the accuracy (precision!) of the model (which is obviously important).

I think that new players in the reloading space especially, are required to wade through a lot of information that often competes and conflicts at times. Maybe there is a better way to communicate the important stuff?

Personally, I spent a lot of time enamored with the OCW method of load development; however after learning more, I see that the variables I was manipulating were unlikely to be having the effect I thought they were. Not to say I didn't develop a good load, but that I probably wasted components unnecessarily for an outcome that I could have likely achieved by picking a random charge weight (RCW method?).

If I recall correctly, one of the famous Greek philosophers described wisdom as being able to see through the bullshit, to the true patterns of reality. Similarly with reloading, I think we want to be identifying the 'true' patterns, and not be fooled by the three-shot groups so to speak.

All this to say, like more learned folk have already suggested - a good platform, combined with a powder and projectile combo that plays nice, some decent fundamentals, and you're likely 90% (or more) of the way sorted.

I think you’re definitely onto a few things here.

Firstly being able to create a simple visual that ranks influential factors in order of influence is gold.

Secondly, and I think if the other thread proves anything, it is that in reloading, it is easy to confuse the noise for the signal and the signal for the noise.

Where your diagram gets difficult, and this is in no way trying to discredit the idea, because I personally do like it, but the difficult part is that accuracy is actually three main triangles in parallel.

One is the rifle
One is the shooter
One is the load

Some aspects of each are independent, others are interdependent, and it is the sum of all, that decides the tightness of the group.

To complicate it further, cost to isolate/manipulate a given variable, isn’t necessarily proportional to the amount of change.
Knowing what is the low hanging fruit helps, and I think in many ways, your diagram seeks to show it.

If the diagram could account for and accommodate all of this, it would really be useful. The hard part is getting it there.

Originally Posted by 19Badger

I would disagree with your chart where you intimate there is less evidence that charge weight and seating depth contribute to accuracy.
They contribute a great deal toward accuracy the biggest contributor to accuracy is your base, the firearm.

I would say the biggest influence on accuracy is the person holding the rifle, when you have someone holding the rifle to shoot you are testing the combination of everything, shooter rifle, bullet, powder, primer, load, seating depth, and the influence of the wind, mirage and everything else.
A lot of things people do will be negated by the person holding the firearm and the conditions of the day.

This is like trying to sight your rifle in and everytime you adjust the sights it shoots in a different place from where your adjustments should make it go.
I see so many use up a box of ammo or more trying to get their rifle to impact on the target where they want it to.

Even in Benchrest shooting the person pulling the trigger can influence the outcome, even though the rifle is supported on a rest and a bench and there are multiple windflags indicating what the wind is doing.

Some can even see the variation in seating depth at 1k
https://www.facebook.com/alex.wheeler.697298

All good points.

For small seating depth changes etc, I would imagine that the 'resolution' of the system will dictate the extent to which differences are able to be resolved so to speak. i.e. it may be an irrelevant variable for the casual hunter with his stock rifle, while important for the competitive bench rest shooter with a highly tuned setup.

It reminds me of one of my other hobbies, hifi audio, where people will frequently argue that you need to have a certain level of fidelity to 'hear the difference' of various equipment (e.g. amps, converters). Lots of voodoo in that hobby too though

Any outcome is dictated by the variables and what you are trying to achieve.

Zeropak made an excellent point, the rifle is separate to the ammunition, you can alter the rifle, ie trigger, bedding, barrel, stock etc change any of those and you need to start the ammunition tuning again.
If the rifle has a fault, ie bedding, fire control, barrel, etc it doesn't matter what you do to the ammunition the accuracy will never be what it could be

To give an example of A "factory" rifle accuracy a Sako 223 with tuned ammunition fired 5 x 5 shot groups at 100yds for an aggregate of 0.600" (15.24mm) for two hundred with a further 5 x 5shot groups the aggregate was 0.4792" (12.172mm) giving a grand agg of 0.5396" (13.706mm)

Of course this is specific to this rifle, but those groups were shot off a front and rear rest by the owner of the rifle.

Will all rifles achieve this?
If you took that ammo and used it in another .223 would the outcome be the same?
If another person used this rifle, the same equipment and the same ammo would the result be the same, better or worse?

From what I understand that rifle has been sold and another rifle purchased, somebody owns a fantastic factory rifle and I'm sure the loading data would have been passed along also.

Originally Posted by longshot

I think you’re definitely onto a few things here.

Firstly being able to create a simple visual that ranks influential factors in order of influence is gold.

Secondly, and I think if the other thread proves anything, it is that in reloading, it is easy to confuse the noise for the signal and the signal for the noise.

Where your diagram gets difficult, and this is in no way trying to discredit the idea, because I personally do like it, but the difficult part is that accuracy is actually three main triangles in parallel.

One is the rifle
One is the shooter
One is the load

Some aspects of each are independent, others are interdependent, and it is the sum of all, that decides the tightness of the group.

To complicate it further, cost to isolate/manipulate a given variable, isn’t necessarily proportional to the amount of change.
Knowing what is the low hanging fruit helps, and I think in many ways, your diagram seeks to show it.

If the diagram could account for and accommodate all of this, it would really be useful. The hard part is getting it there.

Appreciate the feedback.

I probably should be more specific by saying something like "reloading variables affecting precision", to avoid scope creep beyond my intended purpose - i.e. helping newer reloaders. (Obviously there are lots of other factors - something like reading the wind is a useful skill to develop if getting into longer range shooting, however not that relevant for maximising the precision of a certain load and not where you need to start necessarily). What I tend to see is people starting in the middle of the pyramid (e.g. fiddling with 0.2gn powder variations), which seems a less helpful place to begin if your goal is maximising precision.

I think the details of this stuff has all been pretty well hashed out on this forum by gimp and others already, so I don't have any real expertise to add to that conversation - I'm just wondering if it could be communicated in a more succinct way.

I think any good visual model needs to strike a balance between generality and specificity - and probably leaning more towards the former. I probably need to make it more simple, rather than more complicated. Maybe a flow chart might be more useful.

Originally Posted by earplay

Appreciate the feedback.

I probably should be more specific by saying something like "reloading variables affecting precision", to avoid scope creep beyond my intended purpose - i.e. helping newer reloaders. (Obviously there are lots of other factors - something like reading the wind is a useful skill to develop if getting into longer range shooting, however not that relevant for maximising the precision of a certain load and not where you need to start necessarily). What I tend to see is people starting in the middle of the pyramid (e.g. fiddling with 0.2gn powder variations), which seems a less helpful place to begin if your goal is maximising precision.

I think the details of this stuff has all been pretty well hashed out on this forum by gimp and others already, so I don't have any real expertise to add to that conversation - I'm just wondering if it could be communicated in a more succinct way.

I think any good visual model needs to strike a balance between generality and specificity - and probably leaning more towards the former. I probably need to make it more simple, rather than more complicated. Maybe a flow chart might be more useful.

Yeah that makes sense. So if you confine the triangle to load data factors only, it does get much easier.

Ok so I had a play with this idea a bit further. I think I was making things confusing for myself (and others) by trying to be too comprehensive, as in covering all the factors that contribute to precision.

If I go back to my original idea, it was to try create a visual model that might help communicate some of the important factors in load development, especially for new reloaders. While not specific to the load development process, I felt it was important to have the shooter as foundational, as this will in theory set a reference for any load that is developed (assuming precision is part of your goal). I removed a few bits and added some, to try and make it a bit more instructive while hopefully not overly complicated. It's not perfect by any means, but I would be interested to hear if it makes basic sense.

Something to think about, if a 1moa shooter can only shoot groups that are around 1moa with a very accurate rifle how are they going to know they are the weak link in the combination.

If they are using a rifle and ammunition that is only capable of 2moa, how do they know what to improve?

Variables in the shooter and the firearm can give good and bad results.

Love the "start a YouTube channel"

My biggest variable is the loose nut attached to the trigger

I think there's a lot of noise around the issue that is complicating it. It is helpful to go back to the purpose.

to visually represent the primary variables we typically play with when it comes to reloading and precision

When I am talking about these things, there are implicit assumptions:

1. That any shooter error in the system will be more or less constant across the loads tested - which is true if you get reasonable sample sizes.
2. That the rifle is not dysfunctional. I recommend that if you want a high likelihood of good precision (0.1MRAD mean radius or better) with a wide range of bullets and powders, then you can improve your chances of obtaining that by having a good barrel on a good action bedded properly in a good stiff stock.



I think the first diagram is still pretty good.

Originally Posted by 19Badger

To give an example of A "factory" rifle accuracy a Sako 223 with tuned ammunition fired 5 x 5 shot groups at 100yds for an aggregate of 0.600" (15.24mm) for two hundred with a further 5 x 5shot groups the aggregate was 0.4792" (12.172mm) giving a grand agg of 0.5396" (13.706mm)

Of course this is specific to this rifle, but those groups were shot off a front and rear rest by the owner of the rifle.

Will all rifles achieve this?
If you took that ammo and used it in another .223 would the outcome be the same?
If another person used this rifle, the same equipment and the same ammo would the result be the same, better or worse?

- What method was used to tune the load?

- What do all 5x groups look like if overlaid at 100 yards?

- What did loads that were discarded look like - for 5x 5shot groups, or a 25rd overlaid group?

- What does the 5x 5rd group aggregate tell you about what your hit probability is on a target of any particular size?


The evidence I have seen has led me to update my beliefs from the prior position I held. I believed in load tuning with charge weight and seating depth. Now I would say that I haven't seen any convincing evidence that in most circumstances, if you work within the parameters likely to be functional, it is possible to measure any difference.

I have provided dozens of targets of data clearly presented on here - however people keep "telling me" I'm wrong without doing the same. I am more than willing to update my beliefs based on evidence - indeed that's how I got here. Keen to further the discussion with evidence in hand. Show me, don't tell me. Post targets

Originally Posted by gimp

When I am talking about these things, there are implicit assumptions:

1. That any shooter error in the system will be more or less constant across the loads tested - which is true if you get reasonable sample sizes.
2. That the rifle is not dysfunctional. I recommend that if you want a high likelihood of good precision (0.1MRAD mean radius or better) with a wide range of bullets and powders, then you can improve your chances of obtaining that by having a good barrel on a good action bedded properly in a good stiff stock.

Assuming precision is part of the goal - I still wonder if we need to establish some form of baseline as a reference for what to expect.

If for example your average group size, using your (best) factory ammunition is 3 moa - that seems like important information. Like you suggest; where this comes from exactly doesn't necessarily matter as long as it's consistent. However if the shooter is expecting 1 moa groups with their reloads, they may be setting themselves up for disappointment, or a lot of wasted components.

One observation from another voluminous thread, is that it still isn't clear what the OP's system baseline looks like, therefore leading to a lot of conjecture about what variables might benefit tweaking.