@ Zeke- The way I interpreted this statement in the OP is that a load that produces a 1 MOA group at 100 would get .5 MOA at 200 which is how I define better accuracy. How do you interpret it ?
spin stabilization of projectile--yes or no?
- Thread starter stagpanther
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@ Zeke- The way I interpreted this statement in the OP is that a load that produces a 1 MOA group at 100 would get .5 MOA at 200 which is how I define better accuracy. How do you interpret it ?
Me too .
1moa to .75moa is absolutely a smaller group regardless of distance . A 1moa group can't become a .75 moa group with out the trajectory changing correct ?
Which is why I said from the start the question needs to be better defined , It's the very reason I used MOA and not inches . We all know what MOA is and how it's defined . Could I have been more clear , maybe but figured we were all talking in good faith .
Me and very first sentence in my first post said:
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Well at least you guys quit digging, and appear to be starting to climb out of it (hole).
yes i am describing better accuracy as smaller moa at longer distance (see answer in post #19). Even if the group at 100 yds is smaller.
Although technically what we are calling better accuracy is really greater precision?
yes i am describing better accuracy as smaller moa at longer distance (see answer in post #19). Even if the group at 100 yds is smaller.
Although technically what we are calling better accuracy is really greater precision?
"1moa to .75moa is absolutely a smaller group regardless of distance"
A 1 moa group at 100 yds is 1 inch. A .75 moa group at 300 yds is 2.25 inches. A 2.25 inch circle is a larger circle than a 1 in circle in anybody's book, but yours.
A inch is a physical size measurement. 1 in at 100, 200 or 300 yds is 1 inch
MOA is an angular measurement that increases in size at increasing distances.
Minute of Angle
A Minute of Angle (MOA) is an angular measurement. A MOA is 1/60th of a degree. 1 MOA spreads about 1″ per 100 yards. ( actually 1.047″) 1 MOA is a different size at different distances, 8″ at 800 yards is still just 1 MOA.
A wise old redneck ditch digger once said, the longer you dig, the deeper you get.
kilotanker22
New member
Metal God,
I am onboard with your style of thinking. Inertia certainly seems to agree with you here. Once the projectile is headed off course for any reason, the only way to reconcile that would be a change in trajectory.
Discussing spin drift, yaw, group size, is discussing what the bullet is doing. I have not really read where anyone has considered the effect that a yawing bullet will have at supersonic speeds. Personally, I think that the air is more like a fluid at high speeds. The increased air around the bullet would do one of two things. Either it would force the spinning bullet to stabilize, or it would erratically change the trajectory of the projectile. The problem here is understanding how each force is applied to each shot. The fact of the matter is that each shot should be seen as an individual, with specific circumstances relative to itself. A yawing bullet, even if it stabilizes will always continue to move off from the potential trajectory it had at the beginning.
I theorize that people wo experience this phenomenon are not properly accounting for forces applied to the bullet along the entire trajectory. As you mentioned, if your shot is off in the opposite direction the yaw caused the bullet to travel you might see a slight improvement at distance. But that certainly would not be repeatable under controlled circumstances. Are the people observing this effect accounting for temperature, terrain, every possible variation of wind, are the accounting for gravity based on angle cosign? There are so many variables involved that no answer could reasonably expected to be true without eliminating every variable. To consider the bullet's flight without also considering the medium it flies through is a non starter from my perspective.
Seems this would be something best tested in a vacuum, and in a pressurized controlled environment. If the effect is not observed in the vacuum, we could deduce that the effect must be the result of forces present in the atmosphere. If the effect is observed in a vacuum and a controlled atmosphere, then more research to determine why this is possible would be in order.
I am not convinced this is indicative of the bullet's physical properties. It must be the result of other forces causing the effect.
Zeke did you look at the drawing . It shows how big 1moa is at 1, 2&300 yds and the trajectory of a 1moa group/spread notice how the .66moa at 300 yards would have to change trajectory in flight after 100yds in order for the 100yd moa to turn into a .66 moa . group at 300yds
Heres another with your 1moa at 100yds and .75moa at 300yds . Can you see how the bullet path would need to change direction from its 1moa path in order to be .75moa at 300yds
I agree and has been partially my point . There would need to be multiple effects/forces happening upon the bullet to allow it to group smaller down range . To then think those forces would be controllable or consistent enough to draw a conclusion as to there effect just does not seem reasonable , at least not to my tiny brain . Maybe we can get Sheldon Cooper in here to do the math
Heres another with your 1moa at 100yds and .75moa at 300yds . Can you see how the bullet path would need to change direction from its 1moa path in order to be .75moa at 300yds
I agree and has been partially my point . There would need to be multiple effects/forces happening upon the bullet to allow it to group smaller down range . To then think those forces would be controllable or consistent enough to draw a conclusion as to there effect just does not seem reasonable , at least not to my tiny brain . Maybe we can get Sheldon Cooper in here to do the math
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Certainly your drawing clearly demonstrates that a .75 moa at 300 yards is larger than 1 moa at 100 yds, which you also previously disputed. Bullets don't "change direction", and no one ever said they did, but you. Perhaps just another instantaneous translation of what others are saying?
From the dictionary
: the line or course on which something is moving or is aimed to move or along which something is pointing or facing
came from the opposite direction
walking in the same direction
While using a y axis in 100's of yards, and an x axis in several inches seems to indicate some drastic intervention, it is misleading at best. If your graph had the same measurement for both axis, the change would hardly be noticeable. And no where near what most would term a "change in direction".
From the dictionary
: the line or course on which something is moving or is aimed to move or along which something is pointing or facing
came from the opposite direction
walking in the same direction
While using a y axis in 100's of yards, and an x axis in several inches seems to indicate some drastic intervention, it is misleading at best. If your graph had the same measurement for both axis, the change would hardly be noticeable. And no where near what most would term a "change in direction".
stagpanther
New member
Hmmm..I need to clarify--I meant that my groups at a longer distance sometimes tended to be a bit smaller--never meant to suggest they were dramatically smaller all the time. In fact, today I went out and shot my 338 LM at 160 and 260 yds, and I honestly concentrated as hard as I could at both distances but the 260 yd group was tighter. However, I may have simply pulled a few shots at the shorter distance.
The changes being used in the examples given were just examples being used, not actual observed changes. Have said my moa at 300 was noticeably better.
As it turned out, the 168 Sierra tmk carries almost as well as my 140 gn 6.5 cm loads at 600 yds. Haven't used the 175 gram tmk since, although have a modest supply of them.
Have only personally seen this happen in 2 combinations. Both with newer, longer and higher bc bullets in older slower twist rates. It was in concert with a specific bullet in a rifle, not all bullets though the same rifle.
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"What was that about digging holes , never mind I GIVE UP"
Please let me try to explain what your graph is, and what it is not. It is not a trajectory graph. At least not in any common definition of trajectory. It does show moa vs distance. Some would call this type of comparison a rate, like how much moa per 100 yds is a rate.
Now am going to do some instantaneous translation/opinion of my own. Like equating moa measurement with dispersion. One moa accuracy relates to a group of bullet impacts dispersed within an inch at 100 yds. As in 1 in per 100 yards.
Then if you believe that some bullets can become more stabilized at certain distances, and many do not, the same bullet stabilizes at some point and results in a 2.25 in group at 300 yds, aka .75 moa.
This includes the previous rate (1 moa/100 yds) averaged in. The bullets kept dispersing (larger group), just at a lower rate. They didn't change direction or trajectory, they just dispersed at a lessor rate. That is what is represented with the outer lines on your graph. No magical bullets changing direction or magical trajectory change. The bullets just stabilized and stopped dispersing so much, resulting in lessor moa at 300 yds.
Remembering the rates are averages over a distance, the bullets could have stabilized before or after 100 yds. And likely it was gradual, not instantaneous. Also remembering the text pictorials of bullet yaw are usually greatly exaggerated (except when tumbling which has a different name) so as to be seen.
Please let me try to explain what your graph is, and what it is not. It is not a trajectory graph. At least not in any common definition of trajectory. It does show moa vs distance. Some would call this type of comparison a rate, like how much moa per 100 yds is a rate.
Now am going to do some instantaneous translation/opinion of my own. Like equating moa measurement with dispersion. One moa accuracy relates to a group of bullet impacts dispersed within an inch at 100 yds. As in 1 in per 100 yards.
Then if you believe that some bullets can become more stabilized at certain distances, and many do not, the same bullet stabilizes at some point and results in a 2.25 in group at 300 yds, aka .75 moa.
This includes the previous rate (1 moa/100 yds) averaged in. The bullets kept dispersing (larger group), just at a lower rate. They didn't change direction or trajectory, they just dispersed at a lessor rate. That is what is represented with the outer lines on your graph. No magical bullets changing direction or magical trajectory change. The bullets just stabilized and stopped dispersing so much, resulting in lessor moa at 300 yds.
Remembering the rates are averages over a distance, the bullets could have stabilized before or after 100 yds. And likely it was gradual, not instantaneous. Also remembering the text pictorials of bullet yaw are usually greatly exaggerated (except when tumbling which has a different name) so as to be seen.
Let me ask you this Stag , Has your 338 ever shot a better group MOA wise at 100 yards then the best group ever at 300yds . I've never had my best 300+yd group be better MOA then my best 100yd group . This is minimum of 5 shots . I only shoot 30cal bullets but some are quite long like my 195gr ELD-M and the Berger 200.5x . My most common weights are 168 through 190 though .
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stagpanther
New member
Yes, 100 yd grps have been better--but as Zeke said with certain large low drag bullets I do sometimes get better MOA groups at 2 to 300 yds test distances than 100 yds. Yesterday's tests were done with identical loads of 285 gr eldm's driven by 87.4 grs of H1000 seated to COL of 3.74" at both distances. Do I think that this happens often enough that it could withstand statistical probability of being a strong coorelation? Nope. But it's still something that has me curious. It's also possible that it may simply be my eyes tune into the optic better for the given magnification/distance--yet another variable.
The specific 308 combo where the decrease in MOA was observed was a ssg 3000, listed with a 1:11 twist rate, although i have never physically checked it. The 1:11 twist rate was more common in years past, and not encountered so much now a days. Most manufacturers have gone to a 1:10 twist rate specifically to stabilize the longer bullets. Am considering Sierra's 175 tipped match king is a longer bullet, even if it only weighs 175 gns.
So a Criterion barrel with a 1:10 twist rate most likely wouldn't experience the phenomenon being described, especially if using BDC reticle hash marks at longer ranges. IMO, using the hash marks on a BDC reticle isn't precise enough to notice the difference.
"FWIW , I use BDC reticles on my long range rifles and actually use the reticle so the rifle needs to be level to get the proper dope ."
As a flip side, have never experienced any other high power rifle combo getting a better 300 yd moa than 100 yd moa.
So a Criterion barrel with a 1:10 twist rate most likely wouldn't experience the phenomenon being described, especially if using BDC reticle hash marks at longer ranges. IMO, using the hash marks on a BDC reticle isn't precise enough to notice the difference.
"FWIW , I use BDC reticles on my long range rifles and actually use the reticle so the rifle needs to be level to get the proper dope ."
As a flip side, have never experienced any other high power rifle combo getting a better 300 yd moa than 100 yd moa.
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Just out of curiosity Zwke are you talking a single group,or multiple groups. Was it a 3 shot group, 5 shot group, or a 10 shot group using the same bullet/powder/primer combo on the same day under similar conditions or different days.
example - I saw a guy shoot a honest .5 group the other day with a Palmetto Armory AR using bulk ammo @ 100 yards, that does not mean that the rifle can or will ever do it again.
Take your rifle and shoot a pair of 20 round groups at each distance on the same day with the same ammo and then compare them and post pics if you want to convince me
example - I saw a guy shoot a honest .5 group the other day with a Palmetto Armory AR using bulk ammo @ 100 yards, that does not mean that the rifle can or will ever do it again.
Take your rifle and shoot a pair of 20 round groups at each distance on the same day with the same ammo and then compare them and post pics if you want to convince me
Sorry hooddawg, your're welcome to get into a 5,10,15,20 round group test discussion with others. Yet again, and hopefully on a different post. Am preferring to stay on subject. Nor am i going to waste my time or money on 20 round groups to test that shows how well a rifle can maintain it's level of accuracy, which yet again, has nothing to do with the topic being discussed. Nice try though.
stagpanther
New member
I've thought about trying the Litz challenge--sounds like fun, really, but even nicking paper I think could conceivably alter the bullet's flight path somewhat I imagine.
hounddog-thank you