On Target Precision vs. ES/SD?

[SloppyJ]

Let's say you have a load that shoots 10 shots around 0.90moa and one that shoots legit 0.5moa with another and it happens to be 65fps faster.

The larger group has a ES of 10 and a SD of 6. The smaller group has a ES of 20 and a SD of 9 with more velocity. Which one would you choose?

This happened to me with my 300prc today. I verified the slower load of H1000 with 215s and had pretty damn good results. I'd be happy with a 0.9" 10 shot group on any of my rifles. I loaded up some N570 to play around and I literally shot the bullseye out of the target with 10 shots at 100yds. No flyers, no BS, the best group I've ever shot hands down and with my magnum to boot.

I did this after my PRS match and I had to head home so I was unable to move to the 1200yd range to verify at distance. I imagine this MIGHT be where the variation shows itself but after that group, I don't even know what to think. But I will verify it at distance before using it in the field.

I'm trying to think of any reason why I wouldn't pick the N570 load and benefit from not only the tiny group but the extra velocity.

Maybe the conflict is all in my head and fueled by the "single digit ES/SD" talk that everyone always seems to be able to get their load to. Either way, it was a great day. I finished mid pack on my 2nd ever match and I found some killer loads for my 300. My only regret is not waiting until the 4 others guys were done on the range so i could get a picture. I really blew that opprotunity.

I thought this might get some interesting feedback so I decided to see what everyone thought. Thanks!

 

[SDHNTR]

Picking nits

 

[pbroski]

I'd bet those ES/SD numbers would change significantly if the loads were shot again. I would shoot on paper at distance, then decide. It would be interesting to see the result.

 

[SloppyJ]

I'd bet those ES/SD numbers would change significantly if the loads were shot again. I would shoot on paper at distance, then decide. It would be interesting to see the result.

That's the 3rd time i have confirmed the H1000 load over about 50 shots. I'd say I have about 25 for a sample size on the N570. The only difference would be seating depth. But yes I agree somewhat.

The results listed are from today but when you look at the overall sample taken over multiple days, the varibility might be

 

[SloppyJ]

Picking nits

Figured that is the case but what kind of reloader would I be if I didn't obsess on the smallest of variables?

 

[Vern400]

The better group is somewhat factual with repeated 10 shot samples on different days ( and a new batch added would be good)

You won't see ES and SD changes like that matter until you get way past 400 yd. I'm thinking that improved group size is larger in importance than the slight increase of SD and ES. But it's easy enough to calculate anyway with the bullet drop right? Is 50 ft per second more important than 0.4 moa, or not I'd say 600 yds? A few minutes in your ballistic calculator will tell you.

I have seen really, really good groups at 100 yards be plagued by poor ES. They fall apart quickly at 300+

 

[EdP]

My experience is that good stats don't always give good groups but bad stats never give good groups. More frequently, when comparing groups and stats, I find the best groups and the best stats don't always correspond exactly, but are close. In that case I choose the load that gives the best groups. It seems to me this is exactly your situation.

There is a lot of talk here about "your groups are too small," especially for folks trying to draw conclusions from single 3 or 5 shot groups. I don't think that applies in your case. You have done the work and proved the load.

I think it would be interesting to find out what the H1000 would group if you could safely squeeze another 65 fps out of it.

 

[SloppyJ]

My experience is that good stats don't always give good groups but bad stats never give good groups. More frequently, when comparing groups and stats, I find the best groups and the best stats don't always correspond exactly, but are close. In that case I choose the load that gives the best groups. It seems to me this is exactly your situation.

There is a lot of talk here about "your groups are too small," especially for folks trying to draw conclusions from single 3 or 5 shot groups. I don't think that applies in your case. You have done the work and proved the load.

I think it would be interesting to find out what the H1000 would group if you could safely squeeze another 65 fps out of it.

I've certainly tried to squeeze the extra out of it. I wanted to use H1000 because I can get it locally. I havent had much luck in either load at a higher charge weight. I've found pressure with both powders and worked down from there based on consistency and group size. I got lucky and found the seating depth it liked early in the process at 25 thou off. There are certainly faster loads I could make work, but none that I've found that are as consistently precise.

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.

Thank you for the info, I think all that's left is to check both at distance to see how they stack up.

 

[SDHNTR]

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.

Either of those loads will do that with ease. So would a nearly triple digit ES even! Stop the insanity!

 

[Vern400]

I've certainly tried to squeeze the extra out of it. I wanted to use H1000 because I can get it locally. I havent had much luck in either load at a higher charge weight. I've found pressure with both powders and worked down from there based on consistency and group size. I got lucky and found the seating depth it liked early in the process at 25 thou off. There are certainly faster loads I could make work, but none that I've found that are as consistently precise.

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.

Thank you for the info, I think all that's left is to check both at distance to see how they stack up.

Well done. And remember my rockslide musket (308 win) at 500 is game over on deer. Absolutely. You just gonna kill the deer AND it's spirit Good to have the energy margin on elk though. Practice gonna be more important than this choice.

 

[Rippey715]

Good idea to follow Bryan Litz on Instagram.

 

[EdP]

Wow, that blows my approach out of the water.

 

[SDHNTR]

And at 500 yards the difference will be meaningless.

 

[BBob]

Stop the insanity!

Agreed!

Maybe the conflict is all in my head and fueled by the "single digit ES/SD" talk that everyone always seems to be able to get their load to.

Yeah, quit listening to the internet and trust your own testing.


Long range benchrest has figured out that the lowest ES is usually not the one that shoots the best. More often than not the higher ES is better. What you might think is best (aka blind stupid human logic) isn’t always the best.

 

[TaperPin]

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.

 

[Rippey715]

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.

Just as a heads up. If you still have that barrel, Litz will give you $1000 for it.

 

[EdP]

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

I didn't realize that and it changes EVERYTHING. Computer generating the data means every factor we don't fully understand (but can observe) is nullified.

 

[SloppyJ]

Is there a calculator available where you can play with these variables? It seems a bit out there to me that 10fps has a bigger impact at 1000yds than the extra 7.5" that the 1moa group would have.

If that's really the case, my thinking changes. How do people make long range shots without knowing all of the environmentals? There's certainly a huge impact from density altitude and temperature. I know listening to some of the Form stuff on S2H that a wind call is more important than 0.5moa. That makes sense. I'm skeptical on the 10fps.

I hit multiple times on a 12" plate at 1k yesterday with my 6cm. I know my load isn't that tight because I just got the barrel and only had 75rds through it after I verified my dope before the match on that 12" plate. Maybe I'm just a lucky SOB? Or maybe those Dtacs are magic? I guess I'm missing something.

 

[TaperPin]

Just as a heads up. If you still have that barrel, Litz will give you $1000 for it.

It was close to a $1k barrel, but once it was getting burned out I would have gladly sold it to him.

F class and bench guys have documented thousands of rounds fired at distance that group better than the velocity spread should allow - Brian likes to explain it away, but it’s obvious he has done a lot of head scratching on the topic.

 

[BBob]

Brian likes to explain it away, but it’s obvious he has done a lot of head scratching on the topic.

Won't take his blinders off and expand his outlook. How do those guys continually shoot better than his theory? How do guys utilize tuners with such success which he says don't really work?