Central Indiana High Power NRA 1K match - 9/22

[Twangbanger]

Uh, wow. My last extreme spread was 83 over 20 shots. With factory match ammo. Guess this is part of that learning experience everybody talks about.

 

[rhino]

Uh, wow. My last extreme spread was 83 over 20 shots. With factory match ammo. Guess this is part of that learning experience everybody talks about.

What quantity are you kids measuring and how are you measuring it?

 

[Litlratt]

Uh, wow. My last extreme spread was 83 over 20 shots. With factory match ammo. Guess this is part of that learning experience everybody talks about.

Run the numbers on a ballistics calculator with the velocity being the only variable.
POI difference at 1K will probably surprise you.

 

[JonProphet]

20. Lab Radar.

Most testing is done in 5 shot groups. But to see the impacts cross referenced to your scores, look at your velocities. Remember, velocity only changes your verticals.

 

[rhino]

20. Lab Radar.

Most testing is done in 5 shot groups. But to see the impacts cross referenced to your scores, look at your velocities. Remember, velocity only changes your verticals.

. . . that you can measure with that gear under those circumstances.

If the speed is different, the rotational speed will be different too, which will affect the gyroscopic precession ("spin drift" for you guys who like shooting). The faster the projectile spins, the more force will be experienced normal to the flight path. That could affect windage at the point of impact.

But I doubt that the difference is measurable for the situation at hand.

Yeah, I gotta stop doing maths homework before I login to INGO. Notice how I used the plural "maths" to pretend like I'm from a British Commonwealth country? Notice that doing math doesn't just make me even more pedantic than usual, but also makes me even weirder than usual?

 

[Twangbanger]

Run the numbers on a ballistics calculator with the velocity being the only variable.
POI difference at 1K will probably surprise you.

Thanks for the tip. Looks like up to 20 inches of vertical contribution, or enough to almost shrink my last group into a "possible."

This has got me thinking. Not sure where it leads. Do most people find a simple powder trickler adequate to deal with variation on this level?

 

[Litlratt]

20. Lab Radar.

Most testing is done in 5 shot groups. But to see the impacts cross referenced to your scores, look at your velocities. Remember, velocity only changes your verticals.

Add a 10 mph wind to the variables and see if you still argue that velocity only affects verticals.

 

[natdscott]

Add a 10 mph wind to the variables and see if you still argue that velocity only affects verticals.

Gary, you beat me to it.

I'ma flesh that out a little:

Elevation is a relatively simple concept. A bullet fired horizontally may hit the ground at 9,524 miles from the muzzle...but it will still make that impact at the exact same time as a bullet dropped from your hand at the same height.

The velocity at which we project that piece of copper is all that allows it to cover lateral distance BEFORE it hits the dirt. Get that straight: Elevation does NOTHING for improving lateral distance covered; if you throw the bullet straight in the air, yes, it will impact later than the one dropped, but it won't go any further laterally.

So, as an extension of that logic, it's fairly easy to see that a .22 LR doing 1080 fps will not be able to cover as much distance as a a .22-243 Middlestead doing 4,900 fps, even if you could use the same bullet. Right?

I grant you, that is a drastic example I chose for clarity of my point, but I assure you, it is the same discussion for a 185 Berger Juggernaut doing 2,700, versus the one before it that was only clocking 2,645...they'll both still hit the target, but the slower one is going to be behind*, and therefore impact lower on target.


Now windage..

*I chose the term "behind" for a reason. Windage, as a concept, is a little more challenging.

Wind takes time to work on the trajectory of a projectile. In the example above, if you dropped that first bullet from a height of 10 feet in a 100 mph crosswind, you wouldn't really expect it to land right below where you dropped it. Now take the second bullet thrown 10 feet in the air, and allowed to drop 20 feet back to the ground....wouldn't it impact even further downwind?

Of course it would.

The same exact concept applies to actual rifle windage. The longer a bullet takes to cover the distance to the target, the more wind effect it will sustain, and the further from the line between strict point-of-aim=point-of-impact it will diverge. The example is clear: a .22LR at 1080 drifts a whole *^#load more at any range than that Middlestead, and it's not strictly about the difference in bullets**.

As such, extending that logic, you can see that a slower bullet coming out of your rifle will not only hit lower on the target, but due to additional time delay spent in the wind, will also impact further downwind laterally. The 2,645 fps Juggernaut above is quite literally out in the open air longer than, and comes in behind, the one at 2,700.

**Slick bullets do not create less wind effect. Wind effect is limited as a secondary to the fact that slick bullets retain SPEED longer, and take less TIME to get to the target versus how long it would have taken in a vaccuum.


The end result of all this is that, if you want to shoot 10" or smaller round groups at 1,000 yards, you have to get velocity consistency down to a very fine level. 20 fps Extreme Spread (ES) over the entire string is critical on NRA Conventional Targets, and I'm guessing it's gotta be tighter than that for F-Class.

-Nate

 

[rhino]

Ah, I did not consider the flight time increasing or decreasing the time the wind would act on the projectile. That is definitely of concern!

 

[JonProphet]

I guess I was being overly simplistic and putting the cart before the horse. All wind being equal, 5 to 10 FPS in bullet speed from one shot to the next, in my simple mind, wind effect will be the same and bullet shift is highly predictable and consistent. Now you get plus or minus 20 to 30 FPS difference between shots, the same wind will have a bigger impact on POI shift.

Now if winds are varied, then being able to call winds and being able to discern the change in horizontal shift due to wind or bullet speed difference is quite a bit more challenging.

That at is why reloading and consistency are keys to success. It’s step one. Screw up step one, then the dominoes fall quickly there after.

If you hear someone talking about waterline or complimenting you on your waterline, that is specifically, in my mind, a compliment to your trigger pull consistancy and your reloading skill.

-JD-

 

[natdscott]

Concur.

 

[Twangbanger]

I will offer myself up as a case study for this discussion about the effects of velocity variation. I just completed my first 1k match (which also happened to be my first rifle match of any kind with a shot beyond 200 yards). No shame here, I just really want to see what I can learn.

Here is my last target from Saturday (clicking on it will blow it up a little bit). Wind was a pretty-constant 9~10 mph all day, about 45 degrees from Left-to-Right (40 inches of windage were put on to finally center this from LH to RH):



As you can see, my "waterline" goes the other direction.

I know you cannot see the statistics in tiny print down the RHS, but the particulars are:

n=20
Velocity (mean): 1,271 fps. at the target, as measured by the Silver Mountain target system.
S.D. = 20 fps.
Extreme spread: 83 fps.
Actual values, from shot 1 through 20: 1264,1264,1230,1273,1259,1289,1282,1288,1303,1264,1272,1257,1268,1268,1247,1251,1313,1292,1283,1244.
Group size, windage: 1.7 MOA
Group size, elevation: 4.0 MOA

...for those still paying attention, the low and high fps values occurred on shots 3 and 17, respectively. 17 was the second-highest shot on the target; and the two highest shots (17 and 18) were both above the mean. Shot 1 was the lowest on-target, and clocked 1264, just below average.

The correlation between velocity and elevation where the shot ended up is fairly decent. It's not absolute; but if I parameterized these elevations somehow, and correlated them to the velocities, my eyeballs are telling me there would be a good correlation.

Ammo was Hornady Match 6.5 Creed 140gr. ELD at $1.50 a shot. (Don't think I'll be paying for much more of that). I definitely get that I need less velocity variation. But is this ammo? Or is there a "heating-up" effect going on here? The shots are tending to climb as the string goes on.

Rifle is a Ruger American Predator, 100% stock barreled action / trigger/ butt-ugly green plastic stock. 6~7 pound hunting gun, with Harris bipod and shot added to buttstock cavity to bring weight up to 11lbs.

I welcome your instructions, corrections, and general expertise. What gets me the most "bang for the buck" at this point? I will eventually be handloading this caliber. But does it appear this ammo would have performed better with a heavier barrel that doesn't heat up as fast? Or is that not as big an effect as beginners think it is? If I start handloading and counting pepper grains, would a heavier barrel still shrink things even more?

I like this sport. But this has really got my thinker working overtime. It is going to be a loooong winter...

 

[natdscott]

I like this sport. But this has really got my thinker working overtime. It is going to be a loooong winter...

Trust me, it has all of our thinkers working overtime all the time. It's hard, and it's gritty, and that's why it is so worth doing. Just think about your quiet drive home that day.... am I right?!

I'll type more later, but for now, I just offer congratulations to you, sir.

You've now done what the majority are afraid to do, and that was to show up, toe the line, and shoot.

I think you did quite well, in all of the above.

 

[Twangbanger]

...Juar think about your quiet drive home that day.... am I right?!...

I was catatonic, missed my turn and ended up in Mooresville. (That's a no-sh!tter).

 

[JonProphet]

Unless your “perception” of gravity is different than mine, the water line is the “x” axis. Water doesn’t naturally flow vertically.

 

[JonProphet]

Ok, I read your post and to answer your questions, yes.

i’d recommend Buying a reloading manual. Hornady brass in my own over valued opinion is complete garbage. Hornady presses and dies are pretty descent and a solid buy on a budget.

There are a ton of things you can do but ultimately, this hobby like so many others are about how much you can spend in order to max out your talent.

 

[indyjohn]

SD, ES, Sighter #1, Sighter #2, sloughfoot, Litlratt, bag of cat litter? What a great thread!

Terms that will make the young ones scratch their heads.

Great to see you all posting good info here.

 

[Litlratt]

My favorite advice is to buy all the points that you can afford and then practice to get the rest of them.

Barrel/ammo combination is probably the most critical of the system. Admittedly, I'm a Krieger, around 30 of them and Sierra, around 180,000 of them, fanboy.

A mechanically sound scope is required. I still believe that you do not have to be able to see the target, you simply need to know where it's at.

A good, adjustable stock is important. It supports the action and makes it easier to execute good shots (which, in my opinion) is the most important thing in shooting long range.

Triggers do not make a rifle more accurate, but they do make it easier to execute good shots. See above.

As I was a sling shooter, I have limited knowledge regarding rests, bipods and bags.

 

[JonProphet]

SD, ES, Sighter #1, Sighter #2, sloughfoot, Litlratt, bag of cat litter? What a great thread!

Terms that will make the young ones scratch their heads.

Great to see you all posting good info here.

I see where I stand!

 

[Twangbanger]

My favorite advice is to buy all the points that you can afford and then practice to get the rest of them.

Barrel/ammo combination is probably the most critical of the system. Admittedly, I'm a Krieger, around 30 of them and Sierra, around 180,000 of them, fanboy.

A mechanically sound scope is required. I still believe that you do not have to be able to see the target, you simply need to know where it's at.

A good, adjustable stock is important. It supports the action and makes it easier to execute good shots (which, in my opinion) is the most important thing in shooting long range.

Triggers do not make a rifle more accurate, but they do make it easier to execute good shots. See above.

As I was a sling shooter, I have limited knowledge regarding rests, bipods and bags.

I intend to shoot sling also, if I continue with this. That's a new set of variables I haven't uncorked at 1k, yet. (I shot my first match only with bipod, just to see if I could get on paper).

So in your experience, is a vertical string the result of ammo, a fast heating barrel...or do all barrels and ammo simply do this, and the shooter has to learn to read the effect and make compensations as the string progresses?