On Target Precision vs. ES/SD?

[EdP]

Virtually all science begins with the emperical, that which is observed. Then theories evolve to explain the observations and are proven or disproven until what has been observed is explained. When we extrapolate data via computers instead of generating data by actual activity, and then treat the result as valid observation, we have departed from the path of discovery and scientific analysis.

 

[SloppyJ]

Virtually all science begins with the emperical, that which is observed. Then theories evolve to explain the observations and are proven or disproven until what has been observed is explained. When we extrapolate data via computers instead of generating data by actual activity, and then treat the result as valid observation, we have departed from the path of discovery and scientific analysis.

I thought you were being a smartass with your earlier reply and this is exactly what I thought you meant. Thanks for clarifyng.

 

[Vern400]

Many people do, but with accurate rifles I don’t trust 100 yard groups. Many times even moving from 100 to 200 yards has shown much more clarity in group size that applies to longer distances.

On the other end of the stick, Bryan Litz says it should be impossible for group moa at distance to be smaller than 100 yard moa, but I’ve had a rifle that consistently did that for the life of the barrel.

The biggest weakness to the example above is the groups are computer generated.

Nosler ballistics tech support explain to me that in rare cases it is possible. I was shooting 0.48 groups at 100 yards, and 0.6 groups at 200 yards. I never could figure it out. I could do it time and again. I do admit it's pretty rare, but it does happen with certain rifle and cartridge combinations.

 

[Vern400]

So if you want to shoot a deer in the eyeball, pick the tightest group you can get at your expected maximum range.

In my limited experience 400 ~ 500 yards is the range where windrift and elevation variation begin to matter a lot with poor statistical groups ES and SD. I have seen lots of great groups at 100 yards that really stink at 300! This statement is of course limited to BC 0.4 and up, and velocities 2650+

If you're going to be shooting consistently beyond 400 yd, group size, sd, and es and EVEN THE QUALITY OF YOUR BULLET becomes very important. And the level on your scope, and your technique and the list goes on...

 

[Wrench]

My advice is to go paint some rocks and shoot them. If you can connect at your desired range.....that's the goal. If you want to win on paper, there are much better sources of information than here. This is a group of hunters.....there are sites filled with f class and beyond guys. As distance increases the tools and skills change and they sure don't mix well with moving critters who are tough to pull environmentals and range on.

 

[TaperPin]

Nosler ballistics tech support explain to me that in rare cases it is possible. I was shooting 0.48 groups at 100 yards, and 0.6 groups at 200 yards. I never could figure it out. I could do it time and again. I do admit it's pretty rare, but it does happen with certain rifle and cartridge combinations.

That’s almost exactly what my gun was grouping. At first I figured it was a fluke - then it just kept repeating and my shooting buddy tried the gun with the same results.

I’ve suspected it in one other less accurate gun, but it mostly gets lost in the noise - still, 100 yard groupings were consistently 1-1/4 moa and shrank to 1-1/8 moa or a little less at 200 yards. I was too young to make sense out of it, and not curious enough to test it with larger groups.

 

[wind gypsy]

Good idea to follow Bryan Litz on Instagram.
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175 smk with 2650 FPS MV @ 1000 yards is going to be much more subject to distribution from SD than a 215 hybrid at PRC velocities especially if for hunting at shorter than 1000 yards.

The faster, more precise load that still had single digit SD seems like it’d be preferable for states application but I agree with others that there isn’t a bad choice.

 

[EdP]

I thought you were being a smartass with your earlier reply and this is exactly what I thought you meant. Thanks for clarifyng.

No smartassery intended. When I saw the Litz data I got concerned that what I do and had recommended (going with best group vs best stats as long as they are close) was maybe not the right approach. Then Taperpin pointed out that the data was from extrapolation and not actually shot. I was back to "OK, I'll keep doing what I've been doing."

 

[mxgsfmdpx]

I'm looking for that load where when I throw the rifle up on an animal at 500yds, I know that it's game over.

Your shooting abilities, rifle/scope combo, and bullet selection matter way more than any “load” for this type of “guarantee” as I’m sure you already know.

I’m on my second season of pretty much only shooting factory ammo now. The kills keep on coming.

 

[Rippey715]

Just to point out. The Litz experiment is based on two paper targets. One at 100 and one at 300. You shoot through both. In that scenario there has never been an instance of the group on the hundred yard paper being larger than the group on the 300 yard paper. $1000 if you can prove it on a shoot through.

Now shooting a group at 100 and then shooting a totally different group at 200, 300, 400 etc and having that group be smaller than your totally separate group at 100. That’s totally possible and happens often. It’s just statistical noise or dispersion in the data.

 

[TaperPin]

Just to point out. The Litz experiment is based on two paper targets. One at 100 and one at 300. You shoot through both. In that scenario there has never been an instance of the group on the hundred yard paper being larger than the group on the 300 yard paper. $1000 if you can prove it on a shoot through.

Now shooting a group at 100 and then shooting a totally different group at 200, 300, 400 etc and having that group be smaller than your totally separate group at 100. That’s totally possible and happens often. It’s just statistical noise or dispersion in the data.

I’m sure someone will take his money. He’s pretty confident they will as well since $1k isn’t much.

 

[wind gypsy]

I’m sure someone will take his money. He’s pretty confident they will as well since $1k isn’t much.

I'm pretty sure the offer has been standing for years. Seems easy, you should take it.

 

[TaperPin]

I'm pretty sure the offer has been standing for years. Seems easy, you should take it

That rifle of mine was shot out a few decades ago, but someone will take his money. Unless someone wants to do it out of the goodness of their heart, $1k doesn’t cover travel expenses + hassle of travel.

It cracks me up when guys assume a shooter can’t get enough groups to tell this, or that it’s a figment of the imagination.

 

[wind gypsy]

That rifle of mine was shot out a few decades ago, but someone will take his money. Unless someone wants to do it out of the goodness of their heart, $1k doesn’t cover travel expenses + hassle of travel.

It cracks me up when guys assume a shooter can’t get enough groups to tell this, or that it’s a figment of the imagination.

It cracks me up that Bryan Litz and company with their sample size have not seen it but you're positive you have. Lots of shot markers in use at ranges these days. Surely someone should be able to use them to prove it?

Not sure where the whole "challenge" sits now, but here's a thread from 2015 where he said he'd cover expenses.

You are being redirected...

 

[jjohnsonElknewbie]

Shot these groups during load dev for my Tikka T3 lite in 7-08. It has an 18" barrel and KGM r30 can. All shots were at 100 yards with SB 6.5 and 162 ELDX. They were all the same seating depth, and all used CCI LRP. The only component differences were the brass and charge weight, with Federal cases for the 47.2 and 46.7 groups. The 46.5 group was Alpha OCD.

I didn't have a chrono for the 47.2 gr groups (right). I hit pressure for this load, and it was 1 grain under Hodgdon published max.

The 46.7 grain group (middle) had an SD of 13 and ES of 34. Average MV of 2727.

The 15 round 46.5 grain group (left) had an SD of 13 and ES of 44. Average MV of 2628.

I believed that the first two loads shot well enough to take hunting at reasonable ranges. However, I'm glad I took another crack at it before landing on the best load. At 46.5 and with properly sized brass, the rounds feed and extract flawlessly and shoot very well. I don't plan to go down the rabbit hole any further unless the wheels fall off at 200, 300, and 400 yards.

 

[TaperPin]

It cracks me up that Bryan Litz and company with their sample size have not seen it but you're positive you have. Lots of shot markers in use at ranges these days. Surely someone should be able to use them to prove it?

Not sure where the whole "challenge" sits now, but here's a thread from 2015 where he said he'd cover expenses.

You are being redirected...

I’m far from alone in seeing it. There’s a recording of Brian theorizing why it happens - it sure seemed to me at the time he believes it is likely to happen based on the credibility of the shooters he heard it from. At that time his best guess is the bullet is not fully stabilized and flying in somewhat of a cork screw that calms down and self corrects past the 100 yard mark.

That could explain why it’s not seen in short range benchrest that is shot at 100/200/300 - benchrest quality bullets are generally shorter and of higher quality than hunting bullets, and a lot of work is put into ideal bullet stabilization. My gun did it with Nosler partitions.

I doesn’t effect me one way or the other if someone believes me, but solely based on what I’ve seen first hand repeated dozens of times with each group stacking on and reinforcing what was seen in the previous groups, there is no doubt in my mind it’s a real thing.

When he does finally record it everyone will cheer and say how brilliant he is to be the first to discover it! lol

The same with positive compensation - when he records it, he’ll be so very smart to have figured it out.

 

[TaperPin]

If there’s any confusion, what I’m talking about isn’t the same as positive compensation.

 

[Rippey715]

Now to come at this from a different angle.
How much does any of this matter? Let’s say you’re shooting at a 10” target at 400yds. So 2.5MOA or roughly .7 mils.
how bad can your ES be and still be an impact?

With Berger ammo in 300PRC with a 215 going 2940, 4DOF says we should dial 1.4 mils to be on center of target. (Rough estimates) This means we have an elevation budget of .35 mils up or down and still impact the target. So how slow would it have to go to for our dope to be more than 1.7mils or how fast for our dope to be less than 1.1mils?

Fast: 1.1mils at 3175fps
Baseline: 1.4mils at 2940fps
Slow: 1.7mils at 2725fps
ES: 450fps

Wow that’s a pretty huge swing and yet it would still potentially hit your target. Now of course this is a huge swing that we wouldn’t really see in real life. Just trying to illustrate that the actual numbers can be way skewed and still hit. The real difference usually comes down to whether or not the shooter is capable of consistently shooting something like a 2.5MOA target at 400yds. So even though we all want tight numbers and groups for our reloading or factory ammo, it really doesn’t always effect our on target ability as much as we might think. We see guys miss targets at 400yds every weekend and most of them have single digit SDs. Load the best ammo you can, worry less, shoot more.

Good luck

 

[mxgsfmdpx]

The real difference almost always comes down to whether or not the shooter is capable of consistently shooting something like a 2.5MOA target at 400yds.

Nailed it!

 

[mtnbound]

Now to come at this from a different angle.
How much does any of this matter? Let’s say you’re shooting at a 10” target at 400yds. So 2.5MOA or roughly .7 mils.
how bad can your ES be and still be an impact?

With Berger ammo in 300PRC with a 215 going 2940, 4DOF says we should dial 1.4 mils to be on center of target. (Rough estimates) This means we have an elevation budget of .35 mils up or down and still impact the target. So how slow would it have to go to for our dope to be more than 1.7mils or how fast for our dope to be less than 1.1mils?

Fast: 1.1mils at 3175fps
Baseline: 1.4mils at 2940fps
Slow: 1.7mils at 2725fps
ES: 450fps

Wow that’s a pretty huge swing and yet it would still potentially hit your target. Now of course this is a huge swing that we wouldn’t really see in real life. Just trying to illustrate that the actual numbers can be way skewed and still hit. The real difference usually comes down to whether or not the shooter is capable of consistently shooting something like a 2.5MOA target at 400yds. So even though we all want tight numbers and groups for our reloading or factory ammo, it really doesn’t always effect our on target ability as much as we might think. We see guys miss targets at 400yds every weekend and most of them have single digit SDs. Load the best ammo you can, worry less, shoot more.

Good luck

And it’s even more ridiculous now that every shooter has access to an App that will prove this and you still see shooters state this nonsense. I agree 100%, KISS method for reloading and spend more time shooting.