This velocity is impossible isn't it? I'm at a loss.

fuzzynuts54 said:
But like I said both these loads are the top of the node, not one at the top and one at the bottom. I'll take human error out of this also, this wasn't one shot from each load, it was 3 shots with smk - 3 with amax - 3 smk - 3 amax - 3 smk - 3 amax. All groups measure 1-1/4" and less.

I don't get the argument that 100y isn't far enough. 1 bullet of known velocity and bc is being launched at 4.295 moa and everyone agrees that the program can calculate it's point of impact. The next is a known bc and a known point of impact. It's velocity should be just as easy to calculate so long as there are no other variables. Well what are the possible variables here? Barrel harmonics and recoil charachteristics but I feel I've ruled the barrel harmonics out also.

I'm not arguing this, just analyzing ad this is what I conclude. Oh and one more note, this is shooting prone off te bipod, not sandbags. The bipod definatley affects the motion of the gun when recoiling much different than sandbags.
Click to expand...

You keep trying to find a way to rationalize irrational results. If the results don't make sense, it is very likely your "experiment" has some really badly controlled variables.

If you think a three shot group removes human error, you have a lot to learn about science.

The differences in velocity needed to produce a difference in trajectory at 100 yards will be very large (at least one you can measure with any degree of accuracy, which is another variable you ignore).

What on earth makes you think you have ruled out barrel harmonics? You haven't.

What do you think a "node" is? You seem to be using the word in a way I don't understand.

Bad analysis makes for bad conclusions.
 
rral22 said:
You keep trying to find a way to rationalize irrational results. If the results don't make sense, it is very likely your "experiment" has some really badly controlled variables.

If you think a three shot group removes human error, you have a lot to learn about science.

The differences in velocity needed to produce a difference in trajectory at 100 yards will be very large (at least one you can measure with any degree of accuracy, which is another variable you ignore).

What on earth makes you think you have ruled out barrel harmonics? You haven't.

What do you think a "node" is? You seem to be using the word in a way I don't understand.

Bad analysis makes for bad conclusions.
Click to expand...

6- 3shot 1moa groups rule out human error. Ladder testing in .5grain increments from 76 - 80.5 grains puts this load right at the top (79, 79.5, 80 had no measurable poi change) while all lesser loads hit lower and lower. That's a node as I understand it.

I don't actualy belive for a second my velocity is anywhere under 2650 and probably higher. The thread headline is somewhat a goof.

I'm just saying I can feel a difference in recoil. The rifle is resting on a bipod. I feel that the recoil is causing the rifle to jump differently. It is known that a rifle may have a different poi if shot from bipod to sand bags to led sled ext... So it seems reasonable that 2 wildly different loads may induce wildly differend recoil motions when fired from a springy/flexable rest which may be less noticable if these comparisons were fired off a dead rest.

Hopefully the next outting I'll be able to chrono and test bags vs bipod.
 
I have shot my 208's&210's out at near 3100fps with my 300 win mag.
I now shoot my 208's normally at 2950fps. very easily.

You probably have a setting in the program out of sync.
Like maybe your velocity reading is for 300yds, not 100yds.

Youll figure it out I'm sure.
 
Here's my 2 cents....
In post #12 you stated the most accurate load was 77 gr, after finding this you are just burning powder and wearing out your barrel. Velocity does not always mean accuracy. Since I see you are using 150 gr SMK's and 208 gr Amax bullets I assume you are just punching holes in paper. That being said, a slower bullet hitting the V Bull is way better that a very fast bullet hitting a solid 4. As long as the bullet makes it through the target, who cares how fast it is going? In the competitions I shoot in, they don't give points for style or how fast your bullet gets there. The winner is always the person that puts the most rounds into the center of the target.

Where your bullet hits at a given distance is now your Zero for that rifle/load.
Example 1, 150 gr SMK, distance 300 yards, sight/scope setting 10.5 MOA
Example 2, 208 gr Amax, distance 300 yards, sight/scope setting 8.25 MOA.

Start your "come ups" from there.
 
fuzzynuts54 said:
6- 3shot 1moa groups rule out human error. Ladder testing in .5grain increments from 76 - 80.5 grains puts this load right at the top (79, 79.5, 80 had no measurable poi change) while all lesser loads hit lower and lower. That's a node as I understand it.

I don't actualy belive for a second my velocity is anywhere under 2650 and probably higher. The thread headline is somewhat a goof.

I'm just saying I can feel a difference in recoil. The rifle is resting on a bipod. I feel that the recoil is causing the rifle to jump differently. It is known that a rifle may have a different poi if shot from bipod to sand bags to led sled ext... So it seems reasonable that 2 wildly different loads may induce wildly differend recoil motions when fired from a springy/flexable rest which may be less noticable if these comparisons were fired off a dead rest.

Hopefully the next outting I'll be able to chrono and test bags vs bipod.
Click to expand...

I think, for most people, a "node" is the point on the barrel that does not move with the wave motion that is imparted to a rifle barrel by a shot passing through it. A barrel whips like a guitar string when shot. The ideal would be to have a "node" of that vibration at the muzzle, to make all shots hit the same point of impact. In practice, that hardly ever happens. So different loads produce different barrel vibrations, and the resulting POI changes because the muzzle is at a different point in the wave as the bullet exits because the wave nodes produced by different loads are at different points along the barrel.

So what we hope for is that whatever load we use creates a wave that allows the muzzle to be in the exact same position for each shot to make for small groups. But any change in components or powder charge will change the wave motion of the barrel, and make the POI change as well.

That's why Juster said, "Barrel harmonics can mess up the calculation."

That's why CyaN1de said, "Guessing that the barrel node is putting the bullets lower than your known load. If the known is letting the bullet from the muzzle when it is in its high vibration and the new is letting it out on the low vibration the difference is quite possible."

You don't understand all the variables that affect POI, so your results are not valid. Get a chronograph.
 
CyaN1de said:
You would be better to shoot at 2 distances and use the drop between the 2 as your data.

Example:
Shots at 100 are 3" below POA. Shots at 200 are 5" below POA so there is a 2" difference from 100-200

Using that data you can estimate a velocity.
Click to expand...

This.

It is completely useless to compare 2 different loads at the same distance and attempt to calculate a velocity based on the different POI. Worthless. The different PPOI doesn't mean anything except your 2 different loads shoot to a different POI. period.

You need to measure the drop with the same ammo at 2 different distances. Zero at 100 yds, then see what your drop is at 200 or 300 yds. - input that into the calculations and you'll have something worth calculating.
 
Is the chrono setup OK ? I saw some setup where the distance between the sensor was not appropriate (sensors not fully inserted in the bar : CED Chrono) and FPS was not accurate since it's a rule of 3

SB
 
rral22 said:
I think, for most people, a "node" is the point on the barrel that does not move with the wave motion that is imparted to a rifle barrel by a shot passing through it. A barrel whips like a guitar string when shot. The ideal would be to have a "node" of that vibration at the muzzle, to make all shots hit the same point of impact. In practice, that hardly ever happens. So different loads produce different barrel vibrations, and the resulting POI changes because the muzzle is at a different point in the wave as the bullet exits because the wave nodes produced by different loads are at different points along the barrel.

So what we hope for is that whatever load we use creates a wave that allows the muzzle to be in the exact same position for each shot to make for small groups. But any change in components or powder charge will change the wave motion of the barrel, and make the POI change as well.

That's why Juster said, "Barrel harmonics can mess up the calculation."

That's why CyaN1de said, "Guessing that the barrel node is putting the bullets lower than your known load. If the known is letting the bullet from the muzzle when it is in its high vibration and the new is letting it out on the low vibration the difference is quite possible."

You don't understand all the variables that affect POI, so your results are not valid. Get a chronograph.
Click to expand...

this is exactly why I have repeated over and over that the bullet is coming out at the peak of it's node. Peak meaning highest point of impact of all tesed loads. Well actually in the middle of 3 loads that showed no vertical difference between them.

Shure 77 grains was most accurate but it also hit 3" even lower than 79.5. (ladder testing was done at 200y. The 77gr amax load hit 7" lower than the 150smk at that range) I am not a competative shooter, I'm happy with 1moa which this rifle and ammo combo delivers off bags all day long. If I wanted the utmost accuracy I'd change alot of things but I'm fine with what I have. I chose 79.5gr because it has leeway +/- .5 gr before it showed vertical stringing. This is so I feel comfortable in -20*c to scortching hot summer days.
 
look's to me like you don't want to understand...
as said over and over again by others, 2 different bullet will print on the paper at 2 different places, EVEN IF THEIR BOTH "AT THE TOP OF THEIR NODE" LIKE YOU SAY.
just to give another example of this. i went shooting tuesday to find a load for my 7 wsm
using 140 gr gamekings. i brought along a few shells of my hunting loads with 150 gr scirocco's

the scirocco's are making 3/4"-1", 5 shot groups 2" above bull and they went 3103 fps average.
the 140 gr game kings were running 3197 fps average. and were printing 3.5" to the left
of the bull ( that means 2" lower and 3.5" to the left of the 150 gr load) all groups were below 1.35" with the best a perfect 1/2" triangle. but all were centered about the same place. so how do you explain that??? it's shooting on a low/left node???
 
coldmaker said:
look's to me like you don't want to understand...
as said over and over again by others, 2 different bullet will print on the paper at 2 different places, EVEN IF THEIR BOTH "AT THE TOP OF THEIR NODE" LIKE YOU SAY.
just to give another example of this. i went shooting tuesday to find a load for my 7 wsm
using 140 gr gamekings. i brought along a few shells of my hunting loads with 150 gr scirocco's

the scirocco's are making 3/4"-1", 5 shot groups 2" above bull and they went 3103 fps average.
the 140 gr game kings were running 3197 fps average. and were printing 3.5" to the left
of the bull ( that means 2" lower and 3.5" to the left of the 150 gr load) all groups were below 1.35" with the best a perfect 1/2" triangle. but all were centered about the same place. so how do you explain that??? it's shooting on a low/left node???
Click to expand...

I dont doubt that at all, in fact I know it's absolutely true. My 150gr hornady sst's are 1" left. I'm just saying that this COULD Be related to recoil.
It's undisputable that consistent shooting form is important for accurate/repeatable shooting correct?? Why is having the rifle pouting at the target "naturally"? Because recoil will amplify those directional forces yor inducingto keep on target. What do you think would happen if you rested the bottom corner of the butt vs the top corner? It would seem sensable to me that you would get more muzzle rise if you favoredthe bottom of the butt because the bore is much higher.

A simple law of physics tells you that every action has an equal and opposite reaction. A 150gr bullet accelerating to 3300 fps within 24" IS accelerating FASTER than a 208 gr that reaches 2700ish. This is the difference between a sharp recoil and a heavy push.

It is difficult to prove because like you said some bullets simply impact at different places but even a blind monkey should be able to see a possible connection between different recoil motions.

I'm hoping for clear skys so my chrono operates properly. I will also test these 2 loads of a dead rest to see if I can infact prove to myself that the different recoil charachteristics can cause more or less "jump" from a bipod. I expect less noticable results from bags.
 
rral22 said:
Well, that makes it clear. You really don't want to understand.
Click to expand...
Nor do you. Would you mind explaining to me why precision shooter tend o prefer lighter triggers, I mean why would it matter if it were 12lb pull so long as the cross hairs were bang on the x bull when it broke?
Why is it precision shooters say it is important to have a consistent manipulation of the rifle, Why would it matter if you pulled it tight to your shoulder one shot and pushed it away the next?

Are you unfamiliar with the fact that a rifle with bipod tends to jump more off a hard surface than a soft one?
If you are aware if that widely known fact, can you not conclude that shooting different bullet weights, with powders of different burn rates, with different accelerations and different velocitys that create a differet recoils may, just may induce a different muzzle jump in that very same rifle fired off a bipod onthe hard ground.

Perhaps the phenomenon of different bullets hitting left and right is tightly related to the shooter themself. Pistol shooters know this, one guy may group left and low, same gun with a different shooter is high and right. Why is that, any chance it's the shooters grip on the gun that directs those bullets here or there or do the bullets make the decision?
 
fuzzynuts54 said:
Nor do you. Would you mind explaining to me why precision shooter tend o prefer lighter triggers, I mean why would it matter if it were 12lb pull so long as the cross hairs were bang on the x bull when it broke?
Why is it precision shooters say it is important to have a consistent manipulation of the rifle, Why would it matter if you pulled it tight to your shoulder one shot and pushed it away the next?

Are you unfamiliar with the fact that a rifle with bipod tends to jump more off a hard surface than a soft one?
If you are aware if that widely known fact, can you not conclude that shooting different bullet weights, with powders of different burn rates, with different accelerations and different velocitys that create a differet recoils may, just may induce a different muzzle jump in that very same rifle fired off a bipod onthe hard ground.

Perhaps the phenomenon of different bullets hitting left and right is tightly related to the shooter themself. Pistol shooters know this, one guy may group left and low, same gun with a different shooter is high and right. Why is that, any chance it's the shooters grip on the gun that directs those bullets here or there or do the bullets make the decision?
Click to expand...

Find some high speed video of rifles shooting and see when the felt recoil appears.
 
rral22 said:
Well, that makes it clear. You really don't want to understand.
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Hey fuzzynuts,

If you dont get how this different load to different poi thing works, then you dont need to know how fast your bullet is going or what seating depth means or even what gun you have have in your hands! Listen to what people are saying, that's why you posted isn't it!
 
CanuckWR said:
Find some high speed video of rifles shooting and see when the felt recoil appears.
Click to expand...

Great example. Now when do these barrel harmonics come into play because you cant see the barrel move until he bullet exits. Just so you know for next time, the rifle begins it's rearward acceleration the very instant the bullet begins to move forward. The rifle is already set in motion at that very instant and as a matter of mass x velocity it continues to recoil rearward long after the bullet has left the muzzle and depending on bullet velcity and target distance the rifle may still be recoilig well atfer the bullet has already hitits target. But thanks anyways
 
cdn shooter said:
Hey fuzzynuts,

If you dont get how this different load to different poi thing works, then you dont need to know how fast your bullet is going or what seating depth means or even what gun you have have in your hands! Listen to what people are saying, that's why you posted isn't it!
Click to expand...

I absolutely do understand it and very well I'd say. I'm simply including a possible factor that seems to be discredited by some.

We can all agree that shooting the EXACT same rifle and cartridge from different rests... Say led sled, a vice, sand bags, bipod on a soft surface and the "jumpiest" of all.. Bipod on a hard surface are quite likely going to have different points of impact. Google it if you are
a skeptic....

Now it ony seems sensible that if one were to fire 2 loads with different recoil accelerations and velocities off a "jumpy" rest, one
may jump more than the other.

Only a few hundred years ago 99.99999999% of the worlds population though the world was flat. It's a good thing 1 person on the whole planet though differently isn't it.
 
fuzzynuts54 said:
Great example. Now when do these barrel harmonics come into play because you cant see the barrel move until he bullet exits. Just so you know for next time, the rifle begins it's rearward acceleration the very instant the bullet begins to move forward. The rifle is already set in motion at that very instant and as a matter of mass x velocity it continues to recoil rearward long after the bullet has left the muzzle and depending on bullet velcity and target distance the rifle may still be recoilig well atfer the bullet has already hit**s target. But thanks anyways
Click to expand...

Good stuff, you didnt pay attention obviously.

When the bullet is accelerating it causes a "ripple", "whip" or wobble in the barrel. For exactly the reason you have stated above. The point that the bullet exits the barrel, this wobble may be higher or lower than actual POA, hell it may be to the side and a minor deflection of the barrel could equal several inches down range.

SO!!! depending on charge weight, bullet velocity, bullet weight, etc. etc etc... Different loads will exit the barrel at different times relative to the "whip" of the barrel and have a different POI. This is the whole basis of load tuning and why dedicated target shooters us a heavy barrel design. The thicker the barrel the more the "whip" is reduced and load tuning becomes easier. It is also refered to as barrel harmonics, perhaps you have heard of the term?


Now, as you also stated in a previous post about trigger weight. Here is how that works. The more you interact with the firearm the more you are upsetting it, the whole idea behind a light trigger is that the rifle is not upset as much by the shooter. Try a tight grip for a 5 shot group, then try a very loose relaxed grip. You WILL see a different in POI. Try a 5 shot group holding your breath and try one shooting on the bottom of your breathing cycle when your lungs are empty. You may not even be aware of all the small parts of your interactions with the rifle that can seriously upset it. These things are generally what attributes to horizontal stringing on groups, and to be honest what every shooter is training to become consistant with so they shoot better. You have a point with your ideas on the rest attributing to POI changes but I can promise you it has more to do with your technique than the rest. The boys who do this for a living can shoot from an unsupported sitting position better than guys like us from a sandbad rest. Its all about training and technique, be consistant and the rest you use makes very little difference.


Perhaps you could stop being defensive and attacking people when they try to help or dish out advice. Of course this is probably all of our faults for not understanding what you are trying to say.:rolleyes:
 
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