Sub moa at 600
- Thread starter mattt
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fa18hooker
Silver $$ Contributor
1 MOA= 1.047" at 100 yards. At 600 that's 6.282, so .75 * 6.282 = 4.71"...in and IDEAL world, in a no-wind tunnel, and loads that can maintain their consistent velocity at 600. In other words, there's no book answer to the question...and there are 200 pound brains that can answer this better than I, but I thought I'd chime in. The flip side is what I don't understand...how a gun can not group well at short range, but do better at long range...
Im no pro. hell ive never even shot through a cronograph... BUT I think consistant velocities have A LOT bigger effect at 600 than 100.
You could have a load shooting at .5 MOA at 100 but have there being a 100 or whatever FPS varience in that load and it would be way outa wack at 600.
You could have a load shooting at .5 MOA at 100 but have there being a 100 or whatever FPS varience in that load and it would be way outa wack at 600.
Just because your rifle shoots well at 100 does not mean it will shoot well at 600.
Total different ball game....
Total different ball game....
I never said my rifle doesnt shoot at 600 .But the range I practice at is only 100 yards and the range I shoot matches at goes out to 1000. So when I am working on a new load and trying it out at 100 yards I have to use that as my mark on how the load works . thanks for pointing out the obvious Mark
I quit doing load testing at 100 yards for long range loads. I have found some loads that shot well at 100 didn't do as well at longer distances. I do all my load initial load testing at 300 yards now. I see no reason to waste barrel life and components shooting at a distance you won't be competing at unless that's all that is available. I wait for as near perfect conditions to test loads at greater distances and I try to practice in bad conditions.
If your rifle can keep four 5 shot groups under .400" at 100 yards and have an ES under 20 fps for those 20 shots, you should be good to go.
That is if your twist rate, bullet, and velocity are appropriate for long range shooting.
But, as a very good long range shooter stated earlier.
"Just because your rifle shoots well at 100 does not mean it will shoot well at 600"
That is if your twist rate, bullet, and velocity are appropriate for long range shooting.
But, as a very good long range shooter stated earlier.
"Just because your rifle shoots well at 100 does not mean it will shoot well at 600"
Over the years I have learned to follow a simple rule. Now, this is assuming I only have 100 yards to do load development from. For matches 600 or less, I pay more attention to the group size. Outside 600, it’s all about the extreme spread. If the load won’t stay in the single digits for 5-10 rounds it’s not going to a 1K match, I don’t care how tiny the group looks at 100 yards.
I hope this helps,
Lloyd
I hope this helps,
Lloyd
Just curious. Those of you that test 600yd loads at 100yd, do you have issues or signs of poor bullet stabilization? I suspect even at 600yds you are shooting boat tail bullets(although I know some shooting flat based bullets out to 1000yds, and small ones at that). Any keyhole or eccentric holes on your targets? Could this be a part of the problem of testing short of about 300yd where these bullets would stabilize?
Mike
Mike
1shot said:
This is exactly what I done with my 6br just over a month ago. I can now shoot out to 500yrds, from a five min drive from my back door. (now that deer season is over). New Rifle, and a lot of new unknowns for me! Only having 150yrds avaiable at the time of working up the load. I set up at 100 just to keep things on a even keel. I focused on vel. and trusted my chrony. My group size was not that great at 100yrds, But there was hardly any Vertical at all, and I mean no Vertical!! So with the unknown I settled on 30.7gr of Varget with a 105gr berger bullet touching the lands, to take to a F classs match that was shot at 500yrds. I scored from 193 to 197 all weekend. The scores aren't the highest, and should have been a lot higher, If a better shooter was behind the gun! All of my points dropped was due to my mistakes with reading the wind! Not 1 point was dropped due to vertical. Witch comes back to what the chrony was telling me! My ES is 8 and my SD is 3. I do agree with what many have said, the futher out you can go during load development the BETTER, But when you have to make due there is more than one way to skin a cat!!
Mark
mattt said:
Mattt, I was not trying to be a smart ass and didn't mean to come across that way, you have my apology. You asked basically if the MOA that your rifle shoots at 100 will be the same at 600. The answer is not necessarily, its not just a math equation. A 6PPC or 30BR might shoot in the .2s at 100, and yet barely be able to stay on the paper at 600, even in light wind.
I have seen some rifles shoot great at 300, and yet not worth a damn at 1k, for whatever reason - no explanation, just the way it was...
Nothing is a given in the LR world, and there is only one way to know, by trying your rifle and its load combo at distance.
jmatters
Silver $$ Contributor
fa18hooker said:
Dave Milosevich explained it to me this way... Bullets exit the bore not in straight line, but in a sort of spiral (precession). It takes a while for that precession to "settle down" and stabilize. Some loads do so faster than others, and so a load that may not shoot well at 100 yards may be very repeatable at longer ranges.
If a gun shoots a 1” 10 shot group at 100 the best those same shots, in those same conditions, could have done at 600 would be 6”. The bullet angle will not get tighter. A gun's MOA will get proportionately worse as the distance grows because of wind, mirage, a load's standard deviation, and bullet and barrel quality and compatability to name the biggest culprits. The better guns and loads will have groups that stay closer to the short distance angle than others.
You can get a good ways along in finding a 600 yard load by using a quality 600 yard bullet and a crony at 100 yards. For a lot of us it is just too much to turn around and drive back home once we get to the range and find out the conditions aren't so good for long range load testing. What happens then is that some people will shoot in the less than ideal conditions anyway and come away with incorrect assumptions. So it is a viable strategy to work up loads with a crony at 100 or 200, where the conditions play less of a role, and have the field narrowed down for those rare near perfect testing days. But hey, if the conditions are sweet and the distance is there go for it.
If you test mostly at short range with a long range bullet, and I know some good shooters that do, I think you'll find that your long range testing is more a test of the quality of bullet makes and lots.
You can get a good ways along in finding a 600 yard load by using a quality 600 yard bullet and a crony at 100 yards. For a lot of us it is just too much to turn around and drive back home once we get to the range and find out the conditions aren't so good for long range load testing. What happens then is that some people will shoot in the less than ideal conditions anyway and come away with incorrect assumptions. So it is a viable strategy to work up loads with a crony at 100 or 200, where the conditions play less of a role, and have the field narrowed down for those rare near perfect testing days. But hey, if the conditions are sweet and the distance is there go for it.
If you test mostly at short range with a long range bullet, and I know some good shooters that do, I think you'll find that your long range testing is more a test of the quality of bullet makes and lots.
I have some thoughts on this.
Generaly, no, just because your rifle shoots well at 100 doesnt mean it will do well at 600, due to velocity differences and BC differences in your bullets, as well as stability of your bullet. If one bullet stabilizes a bit earlier than other bullets, it will be flying point on for longer, but if it takes a while to stabilize, it will be yawing for longer, right at the time when you done want it to be, at maximum velocity.
Does this sound right to the balistsics gurus here?
Now a rifle which is shooting great verticle at 600 or 1000yds, might not be quite right at 100yds. Not just because of the epicyclic curve either, but because of "regulation". If a load is tuned to shoot well at long range, the lower velocity shots will exit the barrel when the muzzle is pointing upwards in the vibration cycle, while the higher velocity shots will exit the barrel before it gets to the top. This way, at 100 yds, the slow bullets hit high and the fast bullets hit low. At long range the slower high bullet drops down into the group.
This is how my rifles shoot any way. I very rarely shoot them at less than 500-600yds, but when I do, my fast shots hit low by 1/4" moa or so.
Add parralax error at short range to the equation and you get the occaisional case of gun shooting so so at short range and good at longs.
Generaly, no, just because your rifle shoots well at 100 doesnt mean it will do well at 600, due to velocity differences and BC differences in your bullets, as well as stability of your bullet. If one bullet stabilizes a bit earlier than other bullets, it will be flying point on for longer, but if it takes a while to stabilize, it will be yawing for longer, right at the time when you done want it to be, at maximum velocity.
Does this sound right to the balistsics gurus here?
Now a rifle which is shooting great verticle at 600 or 1000yds, might not be quite right at 100yds. Not just because of the epicyclic curve either, but because of "regulation". If a load is tuned to shoot well at long range, the lower velocity shots will exit the barrel when the muzzle is pointing upwards in the vibration cycle, while the higher velocity shots will exit the barrel before it gets to the top. This way, at 100 yds, the slow bullets hit high and the fast bullets hit low. At long range the slower high bullet drops down into the group.
This is how my rifles shoot any way. I very rarely shoot them at less than 500-600yds, but when I do, my fast shots hit low by 1/4" moa or so.
Add parralax error at short range to the equation and you get the occaisional case of gun shooting so so at short range and good at longs.
Mattt,
If your go-to load at 600yards shoots like ass at 100yards, but has minimal vertical, then maybe you're paying less attention to the wind detail when shooting short range? (assuming you're talking about the same rifle in your original post) Most people under-estimate how much a bullet will move at 100 yards by a slight wind. Not saying that you do that, just throwing it out there...
edit... this is coming from a guy who always has 4 in one hole and the 5th shot a 1/4 inch out at 100yards.... every time!
Walt
If your go-to load at 600yards shoots like ass at 100yards, but has minimal vertical, then maybe you're paying less attention to the wind detail when shooting short range? (assuming you're talking about the same rifle in your original post) Most people under-estimate how much a bullet will move at 100 yards by a slight wind. Not saying that you do that, just throwing it out there...
edit... this is coming from a guy who always has 4 in one hole and the 5th shot a 1/4 inch out at 100yards.... every time!
Walt
Assuming zero wind, I suppose the only difference in horizontal dispersion would be barrel harmonics. (Rotation of the earth would have a small effect too 
.)
I'm too lazy to figure out the degree to which it happens, but differences in muzzle velocity will be maginfied at longer ranges - more time for the bullet to lose velocity and drop.
If I was developing loads for long range but only had a 100 - 200y range available, I would want the smallest variation in velocity possible.
John
.) I'm too lazy to figure out the degree to which it happens, but differences in muzzle velocity will be maginfied at longer ranges - more time for the bullet to lose velocity and drop.
If I was developing loads for long range but only had a 100 - 200y range available, I would want the smallest variation in velocity possible.
John
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