Grouping at different ranges

BoogieMan

New member
New rifle 30-06,new loads new scope. I plan to do an initial sight in to get close at 100yds. Then I plan to shoot groups of 3 while working up my load (.5gr at a time). If I do this work at 100yds and find the sweet spot, do I have to start all over at 300, then again at 600? Or is it safe to say that the same load will give similar results at all distances and only need a little tweeking?
 
It is a possibility that loads shoot well at 100 won't at longer ranges. The only way to know is to find the most accurate load at 100 and shoot it at 300-600. Having a good chronograph helps this at it allows you to pick the load with the best standard deviation.
 
If the load has sufficient velocity, there's no logical reason to think it would be accurate at 100 yds, and not accurate at longer range

Some will claim they have loads or rifles that perform better at longer distances, but it's never really been proven

If you have one of the "magic guns", Bryan Litz will pay all your expenses to document the phenomenon

No one has taken him up on the offer so far
 
Save yourself time and money.

Depending on the weight of projectile you're sending, for 3006 you'll have a MPBR of around 275 yards. Your MRT then is about 130 yards. Load development beyond that gets wobbly because of outside influences. If you can get it shooting right at 130 yards there's a better than excellent chance it won't get much better further out.
-SS-
 
the most accurate load at 100 yards will also be the most accurate load at 500 yards and on until you need start messing with staying supersonic and whatnot.
 
If I do this work at 100yds and find the sweet spot, do I have to start all over at 300, then again at 600? Or is it safe to say that the same load will give similar results at all distances and only need a little tweeking?
I would say a charge that shoots great groups 100 often won't show the same result's at 5 or 600.

How I see things:
Targeting a rifle for shorter ranges in hopes to be dead on at longer distances doesn't always pan out. Tweaking your rifle accuracy at shorter ranges will no doubt get you closer to those much further bullseyes. But absolute accuracy needs to be dialed in at the ranges your actually shooting. And at those longer distances there are a lot of variables to consider as I'm sure you already know. Good luck with that endeavor of yours BoogieMan._:)
 
the most accurate load at 100 yards will also be the most accurate load at 500 yards

This.
Once you reach ranges approaching 1000 yards+/- a bit, a 30-06 load becomes subsonic and accuracy suffers. Some loads will remain above the speed of sound a bit longer and accuracy will maintain its self for a few more yards. Only an issue when working right at the limits of a cartridge's ability. But if it is accurate at 100, it will be so at longer ranges.

Some will claim they have loads or rifles that perform better at longer distances, but it's never really been proven

While not common, this has been observed. You won't see a gun be MORE accurate at long range, but they sometimes don't get get worse as expected. If a gun and load shoots 1" groups at 100 yards you'd expect it to shoot 2" or greater at 200 yards, 3" or greater at 300 etc.

I've had a couple of rifles that would do no better than 1" at 100 yards, but shoot 1.5-1.75" at 200 yards and 2.5" at 300. Lots of other shooters have observed the same. Lots of theories why, no proof of anything, just observations.
 
My '06 commonly gave 0.8 MOA at 100 yards. I finally built a 500-yard range at my house. Hmm. Same old 0.8 MOA.

Some guesstimating: For first shots, it seemed like that from field positions of hasty rest, my POI on Bambe was within an inch or so of my intended hit, in the general range of 200 to 400 yards. FWIW. But I've never worried about group size degradation except for wind doping.
 
And why wouldn't it? If your scope and mounts rings shooting technique, loads, bullets everything works at 100, then By all means it should work decent even past 600... What arevyou striving for? Can your rifle scope combo make it? And can you handle wind out to 600?..,,
 
Targeting a rifle for shorter ranges in hopes to be dead on at longer distances doesn't always pan out.
No one is saying that at all

This is about group size, and not zero distance

While not common, this has been observed.
You won't see a gun be MORE accurate at long range

"More accurate than expected" isn't the same as "more accurate than at 100 yds", as some have claimed

To match the claims, a gun would (for example) be shooting consistant 2 MOA groups at 100, and consistant 0.5 MOA at 200

That's why Bryan Litz offered to do the tests and pay the expenses, so accuracy could be measured at several distances to either prove or disprove the assertions

The Applied Ballistics 'Shoot Thru Target' Challange

I'm inviting any shooter who has a rifle which exhibits non-linear dispersion to the Applied Ballistics Laboratory in Michigan to demonstrate the effect. I'll pay your travel and hotel stay (If you successfully demonstrate the effect, I'll even pay your *return* travel as well )

The objective is to produce a repeatable example of this phenomena so it can be studied and hopefully we can learn what's going on.

This is a friendly challenge with the objective of learning. As much fun as it is to discuss all the theories online, I'd really like to actually solve this one.

Any takers?

-Bryan
__________________
Bryan Litz
Ballistician


Read about it here;
http://www.longrangehunting.com/forums/f19/applied-ballistics-shoot-thru-target-challenge-144359/
 
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Thanks for the info guys. What I gather is that as long as Im not shooting minimum velocity loads to get grouping at a 100yds then accuracy (group not POI) should remain constant (without wind) until I get to a point where the bullet is no longer sonic. With a -06 that will likely be somewhere around 1000yds.
I ask the question because I have heard that at short distances a -06 may not stabilize, or maybe I read wrong
 
Shot a mule deer in the neck at 25 yards with my '06. As near as I can tell, the POI was right where I'd intended. Adequate stability, for sure. :)
 
POI changes with distance, for a couple of factors, not only gravity and loss of velocity. Bullet path doesn't just vary vertically, but bullets travel in ever-enlarging spirals, due to imperfections in bullet manufacturing, muzzle flip and rotational precession (movement like a spinning top).

Have you longer-range shooters noticed different POI's, than expected at ever-increasing target distances? You may have attributed it to wind, mirage, etc., but it does occur and is documented by scientific testing.

When sighting-in very accurate rifles, starting at 50 yards, I notice differences in expected POI when shot at 100 and 200 yards that are not attributable to wind, mirage, rest position, shooter technique, etc.

That's why I like to finish sighting-in long-range hunting rifles at the longest "point-blank" distance available and where I prefer to have the bullet strike in relation to point of aim at that distance. POI at closer distances should be within my acceptable limits for field purposes. (Holds on the rest when sighting-in attempt to simulate field positions.)

Final testing is often offhand gong shots at 200 meters, using point-of-aim consistent with expected trajectory at that distance.
 
POI changes with distance, for a couple of factors, not only gravity and loss of velocity. Bullet path doesn't just vary vertically, but bullets travel in ever-enlarging spirals, due to imperfections in bullet manufacturing, muzzle flip and rotational precession (movement like a spinning top).

You may have attributed it to wind, mirage, etc., but it does occur and is documented by scientific testing.

Got any links to this "documentation"?

I'm not buying the everchanging direction, spiraling around some central point.

Bullets do not travel in a "corkscrew" manner

I hear the "spinning top" analogy a lot, when the truth is a top isn't "ballistic", and simply rolls on a flat surface if it spirals
 
"...Same old 0.8 MOA..." Doesn't mean a group of that size at 500 though. One MOA at 500 is 5". If my arithmetic is even close, .8 MOA is 4" at 500. Decidedly unshabby.
"...an initial sight in to get close at 100yds..." Depending on the bullet weight, sighting in about 3.5" high at 100 will put you on target out to roughly 300 yards. Look at the ballistic stables for the bullet drop past there. You don't have to work up a 300 plus load though. You adjust the sights. Just remember that a hunting rifle(and its bullets) may not be capable of really long range accuracy.
Generally, you'd change bullet weights for distances out to 600. A 168 match bullet will do nicely out to 600 and a 175 past there.
"...bullets travel in ever-enlarging spirals..." Whoever told you that is confused? A bullet will stabilize at a particular distance. In the case of a .30 cal., it's roughly 300 yards. Then the bullet stops pitching and yawing(Happens with arrows too. And something you can see with an arrow. It's like a navigation switch gets turned on.) and spins on its axis while dropping and slowing down. No spirals involved.
 
The reason I ask this is because I have no experience beyond 300yds and little experience beyond 100yds. I want to make sure that its realistic to expect the same MOA variance at 300+ that I expect at 100.
I have heard the corkscrew effect many times but it just doesnt make sense.
Wouldnt the bullet be spinning and moving forward at its top velocity a few inches in front of the muzzle? What would make it stabilize at 300yds?
 
Wouldnt the bullet be spinning and moving forward at its top velocity a few inches in front of the muzzle? What would make it stabilize at 300yds?
Muzzle gases can cause a lot of pitch and yaw as it comes out of the barrel, but that tends to go away as distance increases

BUT all that motion is around the bullet's centerline, and NOT around the line of sight, NOR the trajectory path
 
IMHO- As a long range shooter (600 to 1000 yards plus) I will tell you what I have learned. I will never build a load I intend to shoot at long distance by shooting a 100 yards. If I am working up a load it will be at 300 yards minimum. I am not saying it won't work,but I could give you 10 plus loads in a 223 and 20 plus loads in a 308 that will make very small holes at 100 yards, take them out to 600 or more and they fall apart. At 100 yards if a load is going to go South on you, It will not happen that fast. If it works at further distances, then you are good to go, but if it falls apart--Now you have to start all over again. Turns into a lot of wasted powder,bullets and primers. Take the 308 for example,Only because it is so common- You can take one of 8 different powders, 4 or 5 different bullet weights and 3 or so primers. You can zip up a load that will make dime size groups at 100 yards in a heartbeat. What you will find is the majority of them will crash and burn at 300 plus. Again-This is just my humble opinion that I have learned.
 
Sierra Bullets claims their rifle bullets are well stabilized in the first 100 yards of flight shot from the correct twist barrels for the muzzle velocity used. Their 10-shot sub 2/10ths inch test groups at 100 yards and sub 1/3 MOA groups at 200 yards tends to prove that.

No firearm shoots the same subtended angle for groups all the way down range. Here's why.

First off, muzzle velocity spreads cause different amounts of drop for a given target range. Typical drop spread for a .308 Win. at 100 yards with a 25 fps muzzle velocity spread is about 1/20th inch. At 1000 yards, it's 10 inches.

Second, all bullets don't have the same ballistic coefficient (BC). There's up to a few percent or so spread. The best match bullets have about a 1% spread and others as much as 3 to 4 percent or more; depends on quality. That's caused by how much out of perfect balance they are. Those with more unbalance will wobble more in flight and that lowers their BC; they'll drop more for a give time of flight because they've got more drag. At 100 yards, the difference is miniscule but 1000 yards downrange, it can be several inches difference.

Third, subtle cross winds cause horizontal drift. A 1/2 mph change in crosswind for the first 100 yards causes a greater wind drift at 1000 yards than that same change for the last 100 yards.

Fourth, air density isn't uniform all the way to the target; especially those at longer ranges. Bullets drop less in thin warm air than they do in thicker cooler air for a given range band. Their drop at target range will vary due to air density differences.

It all ads up to group sizes increasing 10 to 15 percent for each hundred yards of range after the first one.

There is an exception; positive barrel whip compensation where bullets with slower muzzle velocities leave at a greater angle than those faster ones leaving at a lesser angle. This happens on the barrel's up swing. The Brits proved this reasoning for their SMLE's .303 cordite loaded ammo with huge muzzle velocity spreads over a century ago:

https://archive.org/details/philtrans05900167

Click on the "PDF" line in the "View with" window, then read about it. The Brit's SMLE's typically shot better scores than the USA M1903 rifle in long range matches because of this situation. Their Mauser 98 actioned rifles didn't have this benefit at long range, but did shoot the same ammo more accurate at short ranges where the SMLE's vertical shot stringing was much greater than the Mauser rifles' ones.

Barrel tuners on today's smallbore and benchrest rifles do the same thing about positive compensation. Read about it in:

http://www.varmintal.net/aeste.htm

The US Army and Marine Corps also reported their M14NM match service rifles had a little positive compensation at 600 yards and greater ranges. Evidenced by comparing muzzle velocity versus bullet shot hole vertical stringing at short and long ranges.

I've seen a few new shooters to long range matches with their stuff that they could shoot inside 2 inches slung up in prone at 100 yards with ammo they bench tested at sub 1 inch groups lay down on the 1000-yard line and not keep their shots in the 44 inch black bullseye (8 ring) in perfect shooting conditions shooting scores of 150 out of 200. Then some high ranked friendly competitor loans them their rifle with ammo and they keep 16 out of 20 shots in the 20 inch 10 ring leaking only 4 into the 9 and 8 ring shooting a score of 194.
 
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Those last 2 posts change things a bit. For initial load development I only have a 300yd range available. So, I will get scope on zero with the first few rounds at 100. Dial it up to the 300 mark and work on load development. Is that a sound plan? Is it reasonable for 300yd group to repeat MOA at 600?
Also, on a bit of a side note. What does it take to play the 600yd game? Should I hold my head in shame at a match if I can only hold MOA? I dont need to win (yet) but I dont want to be last either.
 
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