It’s not all about speed - rem 260.

[TassieTiger]

Since putting a new Z5 on my 260 - I’ve been playing around with some load configurations.
Today - I shot my best ever group as a result of pulling back 200fps from what I thought was my best node.
These 120gn Nosler were chrono at 2850fps average which is well below previous node.

I might have to revisit some others as a result.
There is 7 shots in this Target at 150m and wind was gusty 20mph.

260-rem-groups.jpg (36.53 KiB) Viewed 5039 times

[marksman]

the slower node is usually a better target node but the next faster node would be better for hunting
the velocity you are getting is about the same for factory ammo and l do not think any fallow would know the difference

[JimTom]

That is pretty good mate. I’d be sticking with that for sure.

[TassieTiger]

The photo has kicked left twist for some reason - it should be vertical to reflect reality - that’s how it was uploaded...so Fn. red dot is 12mm from memory, so was approx 1 inch high at 150m.
I know I used to be a huge nay sayer for expensive scopes but they do makes things like this much easier - 20x at 150m and reliable loads and my kids could do this....

[Monty]

The photo has kicked left twist for some reason - it should be vertical to reflect reality

Fixed that for you.

[TassieTiger]

Thank you -

[straightshooter]

If you believe you have found one of these mystical so called 'nodes' why is there so much vertical and so little horizontal in a gusty 20mph wind?

[on_one_wheel]

the slower node is usually a better target node but the next faster node would be better for hunting
the velocity you are getting is about the same for factory ammo and l do not think any fallow would know the difference

I would've thought that speed would be helpful for target due to reduced flight time therefore less affected by wind drift ?

All that said, I'm not loading hot. I've chosen barrel life over speed, with the added pleasantness of reduced recoil.

[Harrynsw]

Wow, excellent group...
There's a bloke on YouTube called "260 rips" who as you might have gathered shoots a 260 in some of his vids, any how, pulls of some crazy shots with it, knocking crows off at over 750m away. Freak.

https://youtu.be/Ij-wKwiMYjs

[TassieTiger]

If you believe you have found one of these mystical so called 'nodes' why is there so much vertical and so little horizontal in a gusty 20mph wind?

2 reasons.
The edge of the 200m private road, I shoot From is on edge of an unwalkable cliff.
I imagine my neck tensions still have a lot of work to be done as still getting 50fps difference across my loads.

[TassieTiger]

:shock:
Wow, excellent group...
There's a bloke on YouTube called "260 rips" who as you might have gathered shoots a 260 in some of his vids, any how, pulls of some crazy shots with it, knocking crows off at over 750m away. Freak.

https://youtu.be/Ij-wKwiMYjs

I’ve seen him Harry - he’s certainly skilled.
I’m still learning a lot - and don’t profess to be a marksman by any stretch but you never stop learning and the goal is always the same unachievable impossible group.

This was meant to be a 4 shot group, but when they started touching, I thought...hmmm one more....then one more...then shot 7 when high and I cursed and called myself all manner of names, blamed everything else but me, etc reviewing data - the high shot was 30 FPS slower than some other shots - so that’s now a problem to look at.

[Harrynsw]

:shock:
Wow, excellent group...
There's a bloke on YouTube called "260 rips" who as you might have gathered shoots a 260 in some of his vids, any how, pulls of some crazy shots with it, knocking crows off at over 750m away. Freak.

https://youtu.be/Ij-wKwiMYjs

I’ve seen him Harry - he’s certainly skilled.
I’m still learning a lot - and don’t profess to be a marksman by any stretch but you never stop learning and the goal is always the same unachievable impossible group.

This was meant to be a 4 shot group, but when they started touching, I thought...hmmm one more....then one more...then shot 7 when high and I cursed and called myself all manner of names, blamed everything else but me, etc reviewing data - the high shot was 30 FPS slower than some other shots - so that’s now a problem to look at.

Wouldn't it have hit lower if it was slower ? I dont know, thats why im asking.

[TassieTiger]

That’s the exact issue mate - yes, it should, but sometimes they don’t.

I’ve previously shot a 3 shot group all touching with over 100fps difference in speed - how? Surely the faster bullets would hit higher ? Well neck tension when reloading has a bit to do with it - a tight neck tension can influence pressure...I assume wind gusts can impact as well...as can...temp of bullets.

At longer distance, that high shot would have dropped much faster than some others, making spread bigger...

[Harrynsw]

That’s the exact issue mate - yes, it should, but sometimes they don’t.

I’ve previously shot a 3 shot group all touching with over 100fps difference in speed - how? Surely the faster bullets would hit higher ? Well neck tension when reloading has a bit to do with it - a tight neck tension can influence pressure...I assume wind gusts can impact as well...as can...temp of bullets.

At longer distance, that high shot would have dropped much faster than some others, making spread bigger...

Ok ok I see.

Could've been a slight pull by the said individual maybe? In the heat of the moment when those projectiles are hitting the paper sweeter than cherry pie and the excitement levels are rising....anyhow...

[SCJ429]

If you believe you have found one of these mystical so called 'nodes' why is there so much vertical and so little horizontal in a gusty 20mph wind?

Wind can cause vertical as well as horizontal dispersion. This is because wind can come from any direction, not just from the left or the right.

Don't believe in nodes? What do you call it when the load produces low SD and matches the frequency of your barrel?

I shoot a 260 and with a 140 grain Berger it mystically shoots every bullet to a SD of 1.5 and ES of 3 at a speed of 2803 fps which I identify as a node. Using a Hornady hunting143 grain ELDX it shoots an SD of 7.2 and an ES of 13 at 2901 fps. It can shoot 139 grain Lapua Secnar into groups in the 0.200 at 2930 fps.

If I were you I would push on and see if your load comes together with more speed. That said I am not someone who likes to leave chunks of speed on the table, if you are happy with the speed you are at then stick with it.

[TassieTiger]

That’s the exact issue mate - yes, it should, but sometimes they don’t.

I’ve previously shot a 3 shot group all touching with over 100fps difference in speed - how? Surely the faster bullets would hit higher ? Well neck tension when reloading has a bit to do with it - a tight neck tension can influence pressure...I assume wind gusts can impact as well...as can...temp of bullets.

At longer distance, that high shot would have dropped much faster than some others, making spread bigger...

Ok ok I see.

Could've been a slight pull by the said individual maybe? In the heat of the moment when those projectiles are hitting the paper sweeter than cherry pie and the excitement levels are rising....anyhow...

Absolutely! A tiny twitch at your end can cause large movements at the other.
I’ve taken quite a few new shooters along and it amazes them and me how hard it is to shoot without practice - most ppl I ve encountered, who are new to shooting, will shoot a 4” group In the first couple attempts, then slowly get better to about 2” @ 100 - but I’ve not seen too many who can get better than that in day 1.

Can see also the terrain where I shoot - Wind comes in from right so is all over place.

[Harrynsw]

What more could a man want !
Beautiful.

[marksman]

What more could a man want !
Beautiful.

+1

[TassieTiger]

What more could a man want !
Beautiful.

I’m very lucky having this available and I’ve offered time over - if any members want / need to utilise.

[Harrynsw]

What more could a man want !
Beautiful.

I’m very lucky having this available and I’ve offered time over - if any members want / need to utilise.

Thank you. To kind.

[duncan61]

I am not an expert but my .222 at 2800fps is very accurate.At 150 metres I would not be bothered about wind drift especially with a bullet .260 in diameter.At 900 yards I hear all the full bore guys chatting about clicks and wind drift but with my 168 gn Sierra MK in my 7mm Rem Mag I just look at the target and let them go no allowance for wind at all.We all seem to underestimate how fast centrefire rifles are going and what happens when you hit flesh and bone at close range trust me the extra 200 fps will not matter even a little bit.I am a big fan of using sensible loads.If you need more hitting power get a bigger rifle.The .260 will drop anything in Australia even buff if the shots are placed right.The guide when I did it allowed a hunter to use his 6.5 swede as he claimed it would do a buff and it did

[Flyer]

Wouldn't it have hit lower if it was slower ? I dont know, thats why im asking.

Watch this video: https://www.youtube.com/watch?v=BgD6MtSBfzM

Every action has an equal and opposite reaction. The opposite reaction to rifle twist and recoil is torsion that twists the barrel and shock waves that bend it as the bullet is fired. It is the point at which the barrel is flexing when the bullet exits that determines its trajectory, as well as the speed it is travelling. If the barrel is pointing up when the bullet exits, then the round will hit high at shorter distances regardless of whether it is travelling slower than the round before it if it exitted the barrel when it was pointing at a lower angle. The speed of the bullet as it travels down the barrel also determines the harmonics.

The point of a ladder test is to determine the most consistent "node" where small variations in bullet speed have the least impact on trajectory in relation to barrel movement. There is a lot more to this if you want to have a read about it. Neck tension really shouldn't be a huge issue if you are using quality dies, your brass is not overworked (hard and springy) and you are not crimping your rounds. One way I ensure uniform seating is to put a dry brush down the necks just prior to seating to remove any minor surface corrosion and/or residue that might be have accumulated if you let your finished brass sit for a long time prior to loading.

[TassieTiger]

The barrel on this 260 is heavy and has been cut/crowned 7 times - back to 20.25 inches. Whilst there can be barrel resonance factors in accuracy - my understanding is that they are somewhat mediated with heavier / short barrels.

The vertical dispersion in the target above - although looking largeish - is actually only 15mm @ 150m

This video was posted up previously by Marksman and shows exactly what inconsistent neck tension can do...and it’s not all about brass - an ogive that’s .01 thicker than ogive that’s .01 thinner will create differing neck tension when seating, resulting in higher / lower pressures - differing speeds.
This video is excellent and I’ve watched several times;
https://m.youtube.com/watch?v=Suc0a4UvB1I

[Flyer]

If your rifle has nodes, then those nodes are a product of barrel flex/vibration/harmonics. All barrels flex to some degree, and due to the torsional rotation of the bullet as it is fired, the muzzle generally moves in a roughly circular or elipitcal fashion, as depicted below.



It is correct that shorter, thicker (more rigid) barrels flex less than thinner longer barrels, but it is almost impossible to reduce all flex. That's why you often see barrel tuners (donuts) on benchrest rifles with thick barrels to dampen the vibration.

https://www.youtube.com/watch?v=-iJC-E0yPOA

The idea of ladder testing for a node is to find the point at which the barrel offers the most resistance to flex – the point at which muzzle movement is slowest (least) as the bullet exits – to provide the most consistent results regardless of small variations in velocity, which can never be eliminated, no matter how well you reload.

So, while there may well be other variables at play, harmonics is one possible reason why a slower bullet could hit higher than a faster bullet, as harmonics are influenced by velocity.

I am not saying neck tension is not an issue, but it is not hard to check when reloading and there are ways to make it more consistent. Neck tension affects pressure, which in turn affects velocity, but if your bullets have 0.010" variation – or even 0.01mm – then you have bigger issues than incorrect neck tension as the interference fit with the rifling will have a bigger impact on pressure. That's why variations in neck tension are often related to brass.

[TassieTiger]

How does harmonics account for 100fps difference ?
I cannot change the harmonics of the barrel without going to BR donut devices - but I can get better at reloading. Would it not make sense to fix the controllable variable...a ladder test would be useless with an Es as I’m seeing.
Until I do get better at narrowing that FPS gap (which is neck tension related Or so I believe), so the harmonics become consistent - there’s not much point considering the harmonica or any other musical instrument...

[Flyer]

How does harmonics account for 100fps difference ?

It doesn't. I'm not sure why you would think that.

I cannot change the harmonics of the barrel without going to BR donut devices - but I can get better at reloading. Would it not make sense to fix the controllable variable...a ladder test would be useless with an Es as I’m seeing.
Until I do get better at narrowing that FPS gap (which is neck tension related Or so I believe), so the harmonics become consistent - there’s not much point considering the harmonica or any other musical instrument...

No doubt. But that's not really relevant to Harrynsw's question about why a slower bullet sometimes has a POI higher than a faster bullet.

[TassieTiger]

Yeah kind of is relevant...all things being equal - how would you explain a shot that hits an inch higher on the target but chrono speeds were exactly the same ?

[Flyer]

I wouldn't. I would let you explain it.

[TassieTiger]

Joy to see your back...Quack, Quack.

To Harry - ever time I shoot, I learn something about me, I learn something about the rifle, I learn something about reloading. It’s this appeal that ropes many of us in - some variables are controllable, some are not and within that space, somewhere - is a recipe for success.
The thing that addicted me to motorcycle racing, was the same thing - there is no such thing as the perfect lap and every time you throw a leg - you learn something...game on

[SCJ429]

Yeah kind of is relevant...all things being equal - how would you explain a shot that hits an inch higher on the target but chrono speeds were exactly the same ?

The vibration of your barrel can be plotted as a sine wave, at the top and bottom of the wave your barrel is calmest and bullets go to the same place regardless of small changes of speed. If the bullet leaves the barrel as the sine wave is going up or down the barrel is moving (vibrating) quickly and the bullets will be directed from the bottom of the wave to the top in a very short period of time. Small amounts of speed or timing that the bullet leaves the barrel will cause the muzzle to be in different positions and your groups will be larger.