ES vs Accuracy

[HellsCanyon]

Totally agree.

One other thing I’ll add is that a low ES node doesn’t necessarily mean an accurate load. There’s a well known PRS shooter that only tests for ES on his charge weight tests and then tunes from there. You can get away with that on low pressure 6mm/6.5mm chamberings and heavy AF steel barrels, but it doesn’t cut it for big magnum rifles and lighter weight barrels.
I’ve had more than a few instances of single digit ES but accuracy wasn’t there even after tuning seating depth. Every instance of this however was running max or slightly over recommended pressures. Was able to get accuracy back and still maintain good ES at a lower node.

Good topic!

Mike


Sent from my iPhone using Tapatalk

 

[menhaden_man]

Just did a couple calculations on Hornady ballistics ap and near as I can tell a 50 f/s swing on a 30 cal 178 gr ELDX is about a 16” difference at 1,000 yards (maybe someone can confirm my math).

I don’t kill many animals over 300 yds but wonder if @Ryan Avery is right about overthinking this one. On the other hand, I’d sure hate to miss a nice animal because I wasn’t paying close attention to my rifle. Agree this is a good topic.

 

[Ryan Avery]

Just did a couple calculations on Hornady ballistics ap and near as I can tell a 50 f/s swing on a 30 cal 178 gr ELDX is about a 16” difference at 1,000 yards (maybe someone can confirm my math).

I don’t kill many animals over 300 yds but wonder if @Ryan Avery is right about overthinking this one. On the other hand, I’d sure hate to miss a nice animal because I wasn’t paying close attention to my rifle. Agree this is a good topic.

Don't mistakes what I am saying. Any hunter needs to know their limitations with the weapon they choose to hunt with. But I think too often in LR hunting we get bogged down in the accuracy process when it's good enough. When we should be validating it at extended ranges, or in the mountains finding out what our wind calling limits are instead of tweaking our hundred-yard groups over and over.

Most people shooting sub .5 MOA three-shot group would shit if they shot a ten shot group. Try it sometime.

 

[Reburn]

Don't mistakes what I am saying. Any hunter needs to know their limitations with the weapon they choose to hunt with. But I think too often in LR hunting we get bogged down in the accuracy process when it's good enough. When we should be validating it at extended ranges, or in the mountains finding out what our wind calling limits are instead of tweaking our hundred-yard groups over and over.

Most people shooting sub .5 MOA three-shot group would shit if they shot a ten shot group. Try it sometime.

It's amazing how those one time 3 shot 1/2" groups turn out to be 1.25" 10 shot groups. Going to 10 shot groups was the best and worst thing I ever did.

 

[jakelogsdon]

Out of 4 Long Range hunting rifles I own. Every one would react differently to a 10 shot group. Many more issues come into play IMO. 10 shot groups will teach you more about the characteristics of your rifle and your training as a shooter But I'm not going to lose confidence in my load data.

 

[Reburn]

Out of 4 Long Range hunting rifles I own. Every one would react differently to a 10 shot group. Many more issues come into play IMO. 10 shot groups will teach you more about the characteristics of your rifle and your training as a shooter But I'm not going to lose confidence in my load data.

Variables are a factor but you can eliminate variables by being honest with yourself. An example is my beloved 257 weatherby's. I used to think they were the bee knees. Now unfortunately I know there is better out there. This hasn't decreased my love for the gun just allowed me to accept what it is and isn't. Knowing is over half the battle.

Number 1 is the bullets BC is sub par. It will always be sub par when you stretch them out. The reduced BC affects my wind brackets in a negative way.

#2 The pencil thin barrels lead to POI shift when they heat up. Maybe they aren't properly stress relieved. Maybe they are just not the best barrels and maybe both. Because of this I will shoot 3-3 shot groups +1 allowing the barrel to cool between strings. The chances that I am going to need more then 3 shots in a hunting situation is almost 0. I also track the cold bore impact vs the other 2 shots. Again I recognize what the gun is and what its capable of and that is a factor when I choose to use the rifle.

I'm pretty sure that is the heart of what Ryan was trying to get at.

 

[jakelogsdon]

Variables are a factor but you can eliminate variables by being honest with yourself. An example is my beloved 257 weatherby's. I used to think they were the bee knees. Now unfortunately I know there is better out there. This hasn't decreased my love for the gun just allowed me to accept what it is and isn't. Knowing is over half the battle.

Number 1 is the bullets BC is sub par. It will always be sub par when you stretch them out. The reduced BC affects my wind brackets in a negative way.

#2 The pencil thin barrels lead to POI shift when they heat up. Maybe they aren't properly stress relieved. Maybe they are just not the best barrels and maybe both. Because of this I will shoot 3-3 shot groups +1 allowing the barrel to cool between strings. The chances that I am going to need more then 3 shots in a hunting situation is almost 0. I also track the cold bore impact vs the other 2 shots. Again I recognize what the gun is and what its capable of and that is a factor when I choose to use the rifle.

I'm pretty sure that is the heart of what Ryan was trying to get at.

You just said exactly what I was trying to get at. I guess the jest of what I was trying to say is that if I know my rifles and their abilities and limitations very well, along with my person abilities and limitations. I have no need for 10 shot groups.

 

[netman]

I look at ES as something I can clean up in the off season. Just like making sure your rifle is level before you shoot.
Last year I got ate up with PRS matches on the local level. I shot quite a few matches and that’s what cleaned up some of my shooting.
I was able to get my match rifle ES down to a low number. Then I found I was not shooting a level rifle as I was hurrying.
I found I shot way better when I took six precise shots than I did when I shot ten in a hurry.

 

[new2mud]

It's amazing how those one time 3 shot 1/2" groups turn out to be 1.25" 10 shot groups. Going to 10 shot groups was the best and worst thing I ever did.

Haha--ain't that the truth. (the hard truth, I suppose)

 

[mattstanton]

I do ladder testing at 600 over a lab radar before I ever shoot groups. once I develop a load with an ES of 10 or less, that's when I shoot groups and mess with seating depth.

 

[Wrench]

There is so many variables that can affect ES beyond powder charge and primer. Neck tension, brass thickness, throat conditions, powder temp.....it all plays it's part.

There is also the tolerance in your measuring device. The ohler is going to have tighter tolerance than the chrony.....but let's be real, we are talking about 0.5% accuracy.....there's tolerance stacking going on.

Ryan makes a great point in putting the rubber on the road and physically beating on a known target and recording results.

In field conditions with a fuzz of stress and excitement thrown in, expecting to be a 0MOA shooter (in color, not on the net) is pretty bold....practice brings as much to the table as gear and then some.

 

[menhaden_man]

Haha--ain't that the truth. (the hard truth, I suppose)

Not being a smartass, only asking out of ignorance - can someone explain why a 10 shot group makes any sense?

 

[Reburn]

Not being a smartass, only asking out of ignorance - can someone explain why a 10 shot group makes any sense?

Short answer is to increase your hit probability.

I will explain this the best I can. The first thing you have to understand is guns shoot in cones. Exactly the same as a MOA or MIL is setup. the means that in a 2d world on your target your rifle will shoot into a circle.

Some guys such as myself that are dabbling or profiecient in the long range world want to know our probability of a hit. This is based on a couple things, Target size and cone size of your weapon. The goal is to increase the probability of a hit to as near as 100% as possible.

3 in the statistical world is nothing. 3 isn't enough to draw a conclusion. The sample size is just too small. 10 of something is getting some where. 30 is better. Most guns can manage a 1" 3 shot group accidently a couple times.

What you trying to figure out is what can your gun do ON DEMAND. Not once here or once there if "you do your part". What can you drop down and shoot right now.

So what your trying to figure out is what you ENTIRE weapon system is capable of. Gun, Scope, Rounds and Shooter.

Below is some of the variables that happen when you pull the trigger that make a gun shoot into a cone.

Lets start with the gun you have a barrel. The bullet wont jump the same way everytime from the casing to the lands to continue down the barrel. Also the quality of the rifling and the speed (twist) of the rifling come into play. So does the barrel harmonics. There are some other things I'm going to skip over, Its just too much to type. free floated or bedded barrel. bedded action. stock rigidity. Stock action screw torque, this relates to action and barrel harmonics. Also heat and was the barrel properly stress relieved. barrels shouldnt move their point of impact when they are hot. but many do.

Then you have your scope. Does it hold its zero through repeated firing or does it move tiny amounts. I had a couple vortex on some guns that I couldnt get to group better then 2" 10 shot groups. Many 3 shot groups were touching but together it looked like buckshot. The scope was moving tiny amounts with every recoil. I put a nightforce on the gun and my groups shrank 50% with that one change.

Then you have your bullets. The BC on a bullet has some variable from bullet to bullet withing the same lot. Its small amounts but its there. So is variance of the bullet weight. So is variance in the brass weight. Then there is variance in the primers. Then you have your ES and SD of the round. All this goes back to and can be influenced by your barrel twist and length. No two bullets are exactly the same.

Then there is you as a shooter.

You add all these things up and your gun doesn't shoot exactly the same every time you pull the trigger. Thus you point of impact falls into a cone. The easiest way to determine that cone size is just to shoot some groups. You can shoot 3 shot groups if your barrel gets hot and goes to stringing. Stop. let it cool then shoot 3 more. But shoot at least 10 shots to the same target at the same time. This allows you to make sure your cone is centered over your point of aim. This is also a baseline for how accurate your gun is to start. Also during this time if you have a chrono that doesnt attach to the gun you can chrono 10 shots and see what your muzzle velocity and ES, SD are. With having your velocity you can input that into you ballistics calculator and with your point of impact (POI) directly overlaying your point of impact (POI) you can go verify your gun at range for your drops.

I'm sorry I know this response is very wordy and much more then you asked for. But this is a semi complicated thing to understand and there isn't just a short answer other than to increase your hit percentage.

 

[new2mud]

Not being a smartass, only asking out of ignorance - can someone explain why a 10 shot group makes any sense?

It’s a legit question. A true 1MOA gun will shoot a 1/4 MOA 3-shot group on occasion, and some will claim it as a “1/4 MOA gun!” That is the statistical insignificance at play, with the very rough, over-stretched analogy of even a blind squirrel will find a nut every now and then.

10-shot groups, due to higher statistical significance, are a much better indicator of what the entire system is truly capable of. However, it takes one’s pride and bragging rights down a notch (or five), hence my comment.

 

[Reburn]

Here are some examples. Tested 4 kinds of factory ammo. I don't reload so I just have to live with what the factory ammo will do. You can pick out 3 shots from any group and claim this is a 1/2" or better MOA gun. However when you increase the sample size you see the true capability. All these were 10 shots in a row with no stopping for cooling between shots.

I couldnt get this ballistic X file to upload it was too big but this is the factory ammo my 270 liked the best. The ES and SD were higher then I would like but it shoots well with this round so I went with it.


Close 2nd 145 gr ELD-X


The other 2 kinds of ammo

 

[Reburn]

It’s a legit question. A true 1MOA gun will shoot a 1/4 MOA 3-shot group on occasion, and some will claim it as a “1/4 MOA gun!” That is the statistical insignificance at play, with the very rough, over-stretched analogy of even a blind squirrel will find a nut every now and then.

10-shot groups, due to higher statistical significance, are a much better indicator of what the entire system is truly capable of. However, it takes one’s pride and bragging rights down a notch (or five), hence my comment.

5 notches at least. That why most guys that are doing don't say what their group size is. I haven't see avery or broz say what their group size is at 100. They already know 100 yard group size is significance for like 45 seconds. Then go ahead and go bang steel at 500. Stretch the legs on the gun and see what it will really do.

 

[menhaden_man]

5 notches at least. That why most guys that are doing don't say what their group size is. I haven't see avery or broz say what their group size is at 100. They already know 100 yard group size is significance for like 45 seconds. Then go ahead and go bang steel at 500. Stretch the legs on the gun and see what it will really do.

Thanks for the explanation - and I definitely get the statistical aspect of it. Where I was getting hung up was thinking that folks were suggesting to string together 10 shots as a way to get the rifle to "cry uncle" with a heated barrel, etc. when it is very unlikely that'd occur in the field (at least with deer or elk).

What it sounds like you are saying is that you want to confirm that a 0.5" group (for example) isn't just an anomaly that you happen to capture with the first three shots and call it good.

So... if I string together 10 holes under 0.5" on a single target (no matter the length between shots) with any rifle, then I can start talking chit with all you sharpshooters ?

Also curious who came up with 10? I've seen plenty of guys harp about 5 (which makes sense)... but didn't know if there was any reasoning behind 10 other than being a simple number.

 

[Reburn]

Thanks for the explanation - and I definitely get the statistical aspect of it. Where I was getting hung up was thinking that folks were suggesting to string together 10 shots as a way to get the rifle to "cry uncle" with a heated barrel, etc. when it is very unlikely that'd occur in the field (at least with deer or elk).

What it sounds like you are saying is that you want to confirm that a 0.5" group (for example) isn't just an anomaly that you happen to capture with the first three shots and call it good.

So... if I string together 10 holes under 0.5" on a single target (no matter the length between shots) with any rifle, then I can start talking chit with all you sharpshooters ?

Also curious who came up with 10? I've seen plenty of guys harp about 5 (which makes sense)... but didn't know if there was any reasoning behind 10 other than being a simple number.

Well Kinda. The greater number the group size the better indication of the true accuracy potential of the system. 5 is greater then 3 and 10 is greater then 5. @Formidilosus has long said a 30 shot group but has said 10 is a great start.

However..............

Your rifle shouldn't string shots from a hot barrel. If it is there is likely a couple things going on like I said above. Maybe its a overbore that just gets hot fast 300 RUM, 30 Nosler, 6.5-300 weatherby or any other hot round that makes the barrel hot quick, It can also be the barrel is of low quality, has poor bedding or a free floating problem or not properly stress relieved from the factory. You should shoot 10 shots in a row without cooling. If your rifle "cries uncle" at least you know. My weatherby's do. I chose to not do any thing about it though as I don't want to dump a bunch of money into them. If you rifle can't shoot 3 or 4 rounds without crying uncle there is a larger problem that needs to be addressed. Fact is if it hot strings at all there is a problem with it somewhere. If the Cold bore shot is always your flier you have a problem there too. For example my 6.5 creed barrett fieldcraft doesn't string with 10 shots. Its a full length bedded pencil thin barrel. Neither does my 270 with a bartlien 3b free floated on it. My 2 weatherby's hot string.

I'm for sure not a sharpshooter lol. I'm pretty sure the weak link in many of my rifles is me.

Shooting groups is more or less a waste of time in my opinion. I only shoot groups to verify the ammo is doing what I want and that the POI and POA are both overlaying and chrono. After that I take the rifle out to range and verify drops and adjust BC if needed. After that some shooting for fun at distance, some positional shooting and some wind doping. The goal is to verify that when you miss the weak link is you and not your weapon system.