prioritizing variables affecting POI

Reloading equipment, methods, load data, powder and projectile information.

prioritizing variables affecting POI

Post by on_one_wheel » 16 Oct 2015, 11:42 pm

There are a few obvious factors that affect our ability to controll the consistency of our POI like correctly working up loads, accurately measuring powder weights, projectile weights, getting consistent neck tension, trimming cases to the same lengths , sorting cases by volume, getting neck thickness even and so on.

Can someone shed some light on how to prioritise these things so I can slowly but surely improve accuracy one step at a time in the right sequence so I don't get too far ahead of myself.

I just don't want to find myself attaching one of Peter Brock's polarises to my rifle to align all the good energy when I've still got bigger fish to fry.

EDIT : I didn't mention, rifle setup aside, let's assume your running a solid rig... just thinking ammunition.
Last edited by on_one_wheel on 17 Oct 2015, 3:20 pm, edited 2 times in total.
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Re: prioritizing variables affecting POI

Post by Wm.Traynor » 17 Oct 2015, 10:12 am

POI
Point of impact?
As for accuracy, do you mean group size? IMO, the rifle must be properly bedded first, with no loose screws in rings or mounts. Are you sure of that?
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Re: prioritizing variables affecting POI

Post by Chronos » 17 Oct 2015, 11:55 am

This is a very good topic OOW

For my I prioritise using quality components. No point buying the cheapest cases I can get then putting in hours of prep sizing, trimming and uniforming them only to weigh them and find no more than 50% are within an acceptable range. I do uniform primer pockets as well to give consistent primer seating depth and after a misfiring issue that Apollo helped solved I always seat the primers all the way to the bottom of the pocket.

Same thing goes for bullets, the extra 5-10c per bullet pays off an convlsisyency of length and weight. I once bought a 1000 pack or Remington corelokts and weighed every one on Dillon digital scales. There was around 2.5gr soo read in weight over the batch and no real cluster. I ended up batching them in bags of 50-100 according to weight (.2gr increments)

As long as I use them in order from lightest to heaviest I shouldn't get large changes in poi from one bullet to the next at longer ranges

As for controlling powder charge I change techniques depending to on the purpose. For service rifle I simply throw from a proven reliable thrower directly into the case, check by eye the level looks about right and seat. Same for hunting loads. For target rifles I ended to weigh every charge but I'm now using a Harrel thrower that throws certain powders EXACTLY the same every time so I'm not weighing charges for 6PPC, 6BR or 7X47 anymore. Once you get your load tuned a small variation in powder charge shouldn't make a huge difference to how it shoots. At that point you might choose to be a it less picky with some things.

I'm sure there's a million other things but someone be else will cover them. Crowning, cleaning, parallax, trigger control, body position and scope height are all probable at the top of a list above any loading variations though

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Re: prioritizing variables affecting POI

Post by Gwion » 17 Oct 2015, 6:08 pm

So far, I've found that prioritising consistent charge, finding the right seating depth and neck sizing fire formed cases has given good consistency at around 0.5-0.7moa with my 223rem. Weight sorting bullets and cases shaves a bit off but so did changing powder from BM2 to BM8208. Haven't got around to neck turning and stuff but following these practices have given me the best results so far, having produced two loads consistently under 0.5 MOA.
It comes down to being anal about processes. Only been at it a couple of years but that's been working for so far.

As mentioned above, ammo is the first part of consistent POI. Consistent technique is a constant lesson.
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Re: prioritizing variables affecting POI

Post by Strikey » 17 Oct 2015, 8:42 pm

I have found the biggest variable affecting accuracy is generally the quivering mass behind the butt :D
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Re: prioritizing variables affecting POI

Post by Homer » 18 Oct 2015, 8:47 am

G'Day Fella's,

O_O_W, In addition to the above comments, and to sumarise your questions, basically in my experience, 1) Quality components, 2) Correctly assembled!
#1, Can be purchased #2 Has to be learnt and or taught (FYI, some people should stick to Factory ammo)!

Hope that helps

Doh!
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Re: prioritizing variables affecting POI

Post by on_one_wheel » 18 Oct 2015, 7:40 pm

Here's how I see it, in order of importance
Let's add to the list and play with orders of importance.

1. Finding a projectile that your barrel likes
2. Powder charge / type
3. Seating depth
4. Projectile weight batching
5. Case volume
6. Flash hole uniformity
7. Neck uniformity

Alerady Chronos has added to the list with primer pocket uniformity and primer seating depths , I'd guess that fits in somewhere between 5 and 7 .
I'm guessing by weighing your brass you are probably getting your case volumes even, or are you also cc'ing the cases by fluid measurement?
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Re: prioritizing variables affecting POI

Post by Gwion » 18 Oct 2015, 9:16 pm

Maybe just lucky with my 223rem barrel. It's had 8 different bullets through it in 3 different weights and all (other than win 55 sp factory) have easily found a load at least around 0.7moa or better. This same barrel had been in two different actions.

I'm starting to think that 'the right bullet' is mainly within tolerances of twist rate and suitability of purpose.

Certainly open to other ideas on that.
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Re: prioritizing variables affecting POI

Post by on_one_wheel » 18 Oct 2015, 11:16 pm

Gwion wrote:Maybe just lucky with my 223rem barrel. It's had 8 different bullets through it in 3 different weights and all (other than win 55 sp factory) have easily found a load at least around 0.7moa or better. This same barrel had been in two different actions.

I'm starting to think that 'the right bullet' is mainly within tolerances of twist rate and suitability of purpose.

Certainly open to other ideas on that.


I recon your right , just as long as there is enough twist to stabilize it and not too much so it over stabilize it.
I spent the afternoon working up 70 gn projectiles for the .243 , years ago I decided that 100's worked best in my rifle, today I got the 70's to group just under 1" but ran out of time for further development... not quite the .5 moa I achieved from the 100's but I probably burnt the barrel out working up that load. :lol:
Sorted my prepared cases by weight before I loaded them, first time I've done that.
Unfortunately despite tlc and annealing this batch of brass is on its last legs,
It's been fired 5 times now and is showing signs of stress in the form of split necks..
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Re: prioritizing variables affecting POI

Post by Gwion » 19 Oct 2015, 5:54 am

What a bugger! I'd have expected annealing would give you a longer life than that.

What charge weight increments have you been testing at?

Too bad brass bullets are so expensive. A 70gn brass bullet would probably touch the lands and still have good seating due to being longer because of lighter construction material and give you more chance to find your sweet spot with seating depth.... but that's a bit off topic.

My next priority on consistently precise ammo is neck tension. Gotta work on getting it even and consistent.
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Re: prioritizing variables affecting POI

Post by on_one_wheel » 19 Oct 2015, 8:57 am

Gwion wrote:What a bugger! I'd have expected annealing would give you a longer life than that.

What charge weight increments have you been testing at?

Too bad brass bullets are so expensive. A 70gn brass bullet would probably touch the lands and still have good seating due to being longer because of lighter construction material and give you more chance to find your sweet spot with seating depth.... but that's a bit off topic.

My next priority on consistently precise ammo is neck tension. Gotta work on getting it even and consistent.



I've been going up in .5 grain incriminates , I'll do some finer tuning once I think I'm close.

I'm a little surprised about the brass too, I'm considering binning the old brass before I see a case head separation.

I did consider solid copper projectiles but I doubt they would give me the explosive power I'm after.

I recon apc style projectiles are better suited to large game where weight retention is what tour after, it's a shame realy because I'd like to be running less than 5mm jump.

Have you bothered with neck reaming for even neck tension ?
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Re: prioritizing variables affecting POI

Post by Gwion » 19 Oct 2015, 9:19 am

Nothing to ream it with.

Just ordered a neck turner this morning, so that should make a difference. Its the Forster Original Trimmer with a neck turn accessory.

I've seen these brass bullets called Raptors, they make a 243 65gn with a massive cavity filled with a removable plastic tip. They are apparently designed to be frangible and the speed you could push them in a 243 would be impressively explosive, i'd guess. BUT, they are HORRENDOUSLY expensive!!!

My approach from the o.5 test is to then go o.2 either side of the best one, then o.1 either side of the best of those two. Constantly amazed how much difference a small difference in powder charge can make, even in a 308 sized cartridge.

A 5mm jump is like a yawning chasm! Is there anything longer you can try in the same weight???
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Re: prioritizing variables affecting POI

Post by <<Genesis93>> » 19 Oct 2015, 11:06 am

so..... are you talking target shooting on a bench? in the field off-hand hunting, or prone or leaning on a tree? shooting in different environments? mountains, sea level?

Before the countless variables are considered, the one thing in my simple mind, that will discount the many hourse of case prep, measuring,shaving reaming weighing sorting case bullet etc... is consistent charge, if the charge is not sufficiently consistent, then all the hours of dancing around doing those special things to your cases, that sound kind of really important and necessary will be FUTILE... pissing in the wind...

So... if you're competing at BR comp, or just doing your solo best... yes, by all means - if you're in the field, taking a shot when and where presented, firing from a tree rest, or your knee, or your mates shoulder.....honestly..... :)
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Re: prioritizing variables affecting POI

Post by Gwion » 19 Oct 2015, 11:37 am

If you read the original premise, the topic is about producing consistent hand loads. Not about how good can you shoot, or how good can your rifle shoot; just how consistently precise is your hand load ammo and what elements of hand loading have the greatest impact on the ammunition's precision.
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Re: prioritizing variables affecting POI

Post by <<Genesis93>> » 19 Oct 2015, 2:18 pm

Yes, thank you, I did read the post.... and I must have missed the premise.... which part was the premise??

....and everything is about how good you can shoot.

You keep sorting your bullets by mass (not weight, I can explain you difference just for you if you like :friends: ) while shooting off a field tree rest....
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Re: prioritizing variables affecting POI

Post by Gwion » 19 Oct 2015, 3:50 pm

There was a premise established early in the thread, that certain factors and processes in the manufacture of hand loaded ammunition can lead to greater precision from a particular firearm; this being a premise (verb) not the premise (noun). It was then posed: what was peoples opinions as to effectively prioritising these factors and processes. It was also clarified that the shooters influence had greater effect than the finer details of handlboading and that we were assuming a perfect world as far as firearm precision and shooting technique; thereby reducing the discussion to prioritising the factors and process that lead to consistently accurate and precise ammunition.

We are all, in the main, aware that 'mass' is technically correct; however; in the general parlance of most of the English speaking world; weight is fully understood as a synonym within the vernacular.

By all means, throw any kind of components in your ammunition or load your firearm with whatever happens to be lying around and shoot out to 800m off your mate's shoulder. I'm sure that in doing so you could out shoot anyone here.

However, comments shaped so as to denigrate other's efforts to produce the most accurate ammunition they are capable of producing are unnecessary, somewhat off topic and contribute little to the discussion. :drinks: :friends:
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Re: prioritizing variables affecting POI

Post by Chronos » 19 Oct 2015, 4:28 pm

Gwion wrote:There was a premise established early in the thread, that certain factors and processes in the manufacture of hand loaded ammunition can lead to greater precision from a particular firearm; this being a premise (verb) not the premise (noun). It was then posed: what was peoples opinions as to effectively prioritising these factors and processes. It was also clarified that the shooters influence had greater effect than the finer details of handlboading and that we were assuming a perfect world as far as firearm precision and shooting technique; thereby reducing the discussion to prioritising the factors and process that lead to consistently accurate and precise ammunition.

We are all, in the main, aware that 'mass' is technically correct; however; in the general parlance of most of the English speaking world; weight is fully understood as a synonym within the vernacular.

By all means, throw any kind of components in your ammunition or load your firearm with whatever happens to be lying around and shoot out to 800m off your mate's shoulder. I'm sure that in doing so you could out shoot anyone here.

However, comments shaped so as to denigrate other's efforts to produce the most accurate ammunition they are capable of producing are unnecessary, somewhat off topic and contribute little to the discussion. :drinks: :friends:



given that none of us are ever going to fire our rifles in any other gravitational environment i'm happy to use the term weight :thumbsup:

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Re: prioritizing variables affecting POI

Post by on_one_wheel » 19 Oct 2015, 4:34 pm

Genesis 98 what I am hoping to do here is pick the brains of people who are into producing ammunition of unequaled precision in order to learn as much as I possibly can about the black art.
I can see myself heading towards some kind of competition style shooting one of these days, and not the off the tree stump style you speak of.
For now , it's learning about producing fine ammunition and trying my hand at busting varmints at long ranges from the prone position using a solid F class style rest and rear bag.
Hopefully with good positive input to the thread we can all learn something along the way.
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Re: prioritizing variables affecting POI

Post by on_one_wheel » 19 Oct 2015, 4:50 pm

Gwion wrote:Nothing to ream it with.

Just ordered a neck turner this morning, so that should make a difference. Its the Forster Original Trimmer with a neck turn accessory.

I've seen these brass bullets called Raptors, they make a 243 65gn with a massive cavity filled with a removable plastic tip. They are apparently designed to be frangible and the speed you could push them in a 243 would be impressively explosive, i'd guess. BUT, they are HORRENDOUSLY expensive!!!

My approach from the o.5 test is to then go o.2 either side of the best one, then o.1 either side of the best of those two. Constantly amazed how much difference a small difference in powder charge can make, even in a 308 sized cartridge.

A 5mm jump is like a yawning chasm! Is there anything longer you can try in the same weight???


I'll have to do some homework on these raptors and similar led free projectiles.

5mm sure is a dare devil sized jump
In hindsight I should have gone for flat tailed projectiles instead of boat tails, that would make the difference needed to get close to the lands.
I only bought a 100 pack so it's no big loss there.
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Re: prioritizing variables affecting POI

Post by Gwion » 19 Oct 2015, 5:02 pm

OnOneWheel, look up meplat.com.au and go to online store/brass hunting projectiles. They look awesome but man they will send you broke!!!

I guess your idea of a flat base will give you more seating area to play with.
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Re: prioritizing variables affecting POI

Post by Turtleburp » 19 Oct 2015, 8:05 pm

<<Genesis93>> wrote:Yes, thank you, I did read the post.... and I must have missed the premise.... which part was the premise??

....and everything is about how good you can shoot.

You keep sorting your bullets by mass (not weight, I can explain you difference just for you if you like :friends: ) while shooting off a field tree rest....


Easily missed - its in the reloading section rather than explicitly stated and all the variables relate to reloading

Shame really, I was hoping to comment on wind and being a pom I would have thought it bloody hilarious
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Re: prioritizing variables affecting POI

Post by Joom » 22 Oct 2015, 9:59 am

on_one_wheel wrote:5mm sure is a dare devil sized jump


Yep :shock:

Can't be good for the barrel throat having the projies fly into it like that...
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Re: prioritizing variables affecting POI

Post by Strikey » 22 Oct 2015, 10:41 am

Joom wrote:
on_one_wheel wrote:5mm sure is a dare devil sized jump


Yep :shock:

Can't be good for the barrel throat having the projies fly into it like that...


Why? Copper and lead is softer than the steel from which barrels are made, it is the several hundred degrees of heat generated from the burning powder that erodes the throat ;)
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Re: prioritizing variables affecting POI

Post by Vati » 26 Oct 2015, 2:08 pm

Chronos wrote:No point buying the cheapest cases I can get then putting in hours of prep sizing, trimming and uniforming them only to weigh them and find no more than 50% are within an acceptable range.


What's your acceptable range out of curiosity?
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Re: prioritizing variables affecting POI

Post by Chronos » 26 Oct 2015, 2:22 pm

Vati wrote:
Chronos wrote:No point buying the cheapest cases I can get then putting in hours of prep sizing, trimming and uniforming them only to weigh them and find no more than 50% are within an acceptable range.


What's your acceptable range out of curiosity?


It would depend on a few things. I've read where some people say 1% for high level benchrest 2% for disciplines like F class or palma where there's a larger human element and 3% for hunting but it depends on how many cases you are willing to put aside.

The last batch i weighed i just batched them all by weight and took out the couple of lightest and the heaviest. I used these to make dummies and an OAL gauge by tapping out the base for the hornady OAL gauge

I know others just sort them in order of weight and use them in order so they never get a low volume case in a 5 shot group of light (high volume) cases it's a good system as i should reduce the change of a flyer but i tend to tumble them all together so they's never stay in order for me

Remember there's no point weight sorting until all the cases are exactly the same shape and length. this means fireforming, uniforming, trimming, neck turning etc. that means they should all have near identical outside dimensions. at that point any weight variation should be due to thickness variations and that will equate to internal volume differences. it's really a shortcut to uniforming case volume without actually checking the volume of every case

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Re: prioritizing variables affecting POI

Post by Norton » 28 Oct 2015, 1:47 pm

Strikey wrote: Why? Copper and lead is softer than the steel from which barrels are made, it is the several hundred degrees of heat generated from the burning powder that erodes the throat ;)


I assume he means having the bullet potentially impact the lands fractionally off-centre, rather than sliding into the throat as they would if seated just off them.

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