6BRA Ladder Test with/wo Tuner

[TZaun]

Thanks @dmoran. This is what I was looking at when reading about looking at the sine waves and why I couldn’t see hardly any correlation between the two targets that way. I find it interesting that the loads with the tuner shot flatter on the whole POA plane but chart out much choppier than the non-tuner loads do. I also find it interesting that the vertical dispersion is actually worse with the tuner on despite the ES being better, on average.

 

[dmoran]

@flamethrower
Made a new chart and edited my Post #72 with it, subtracting bullet diameter (.243) from all the gross measurements that I had listed/charted. Should have done that originally, and Thank you for pointing it out.
Donovan

 

[BartsBullets]

Correct, thank you, so......... In Barts examples here, why do I see the frequency increased with the added mass (up and down QUICKER), and amplitude reduced (up and down with LESS extreme spread)? Who knows, maybe Bart just can't shoot straight at 100 yards


Tom

Well there is that!

 

[KenOath]

Correct, thank you, so......... In Barts examples here, why do I see the frequency increased with the added mass (up and down QUICKER), and amplitude reduced (up and down with LESS extreme spread)? Who knows, maybe Bart just can't shoot straight at 100 yards


Tom

Was thinking maybe Bart missed the wind on a shot or two.... but this discussion was getting a little heated between some heavy weights so I thought I’d stay out of it... but now Tom has bought it up is there a possibility the wind or Bart’s shooting (sorry Bart) has moved things around a little??

Cheers Rushty

 

[BartsBullets]

Was thinking maybe Bart missed the wind on a shot or two.... but this discussion was getting a little heated between some heavy weights so I thought I’d stay out of it... but now Tom has bought it up is there a possibility the wind or Bart’s shooting (sorry Bart) has moved things around a little??

Cheers Rushty

Oh Hell yeah it was was blowing 10 to 15 and switchy. I’m a little rusty!

 

[KenOath]

Oh Hell yeah it was was blowing 10 to 15 and switchy. I’m a little rusty!

May I suggest retesting in some more favourable conditions...!

Cheers Rushty

 

[BartsBullets]

I am in agreement with Tom in his understanding of amplitude

The amplitude of wave should change from hanging extra ounces of tuner off the end of the barrel so instead of having high peaks we would have shallower peak and valleys from the same amount of energy. this seems apparent in the bullet impact in the turner test as almost the entire string falls on or below the line compared to the non tuner test

Based on the tuner target i would select 30.6 over 31.6 however the 31.6 on the tuner would need to be re-tested as the speed is the same as the 31.4. it is also lower then the no tuner speed by 8fps which is the largest low spread between all of the tuner no tuner velocities

I would further re-test 3rd time the 30.8 to confirm the size of the window for 30.6, in both 30.8 samples the ES is above 10 yet the two preceding and the one after the 30.8 have ESs under 4.

What i expected but didn't materialize see Dmoran vert chart is that there is more vertical in the tuner loads then the non turner (free flowing barrel) as a whole.

My I suggest running the test again with the turner 1 full turn further out.
What i expect is it will lower the groups further below the line and subsequently reduce vertical to display tighter groups compared to the non turner groups.

All the best
Trevor

Trevor,

I shot 30.8 twice with the tuner on. You can see the other 30.8 at the bottom of the target. Then once without the tuner. All three of the groups sucked. Pretty sure it didn’t like that load!

Bart

 

[dmoran]

I shot 30.8 twice with the tuner on. You can see the other 30.8 at the bottom of the target. Then once without the tuner. All three of the groups sucked. Pretty sure it didn’t like that load!

I agree, and obvious enough to me. Especially since 30.8 was a 3-peat... lol

Can respect moving on and trying something different, but a retest as some are alluding, I can only ask why and myself see no reason to. Bart is an accomplished shooter and has a great testing facility. I credit this test and all his shared tests/results over the years in high regards and credibility.
Just saying...
Donovan

 

[Trevor60]

Trevor,

I shot 30.8 twice with the tuner on. You can see the other 30.8 at the bottom of the target. Then once without the tuner. All three of the groups sucked. Pretty sure it didn’t like that load!

Bart

I can appreciate you recognized the group and shot it a second time using the tuner. i observed both groups where the es was 11 and 14 three times larger then your typical es spread. Your tightest group was shot with 30.6. followed by your largest group at 30.8 the fall off appears to be outside the curve. I suggested a third time to define where your margin lies 30.5 or 30.6. running along the edge can be frustrating.

I have a bias I disdain 2 and 1 groups. where the first two go into the same hole and the third takes off. there is more to question in those groups.

All the best
Trevor

 

[BartsBullets]

I can appreciate you recognized the group and shot it a second time using the tuner. i observed both groups where the es was 11 and 14 three times larger then your typical es spread. Your tightest group was shot with 30.6. followed by your largest group at 30.8 the fall off appears to be outside the curve. I suggested a third time to define where your margin lies 30.5 or 30.6. running along the edge can be frustrating.

I have a bias I disdain 2 and 1 groups. where the first two go into the same hole and the third takes off. there is more to question in those groups.

All the best
Trevor

I certainly understand your point! In short range we get this a lot when a load is too hot. It will bury two shots and pitch one. There was no reason condition wise for the bullet to take off like it did. It was so far out that I wanted to confirm the results. At 100 yards ES may be an indicator of the “health” of a load at but has virtually no effect on vertical at this distance.

I’m on a bit of a weather hold but my next step is to take some of these loads out to 500 yards and see what they will do. Matches are coming up shortly and I’d like figure out what I’m going to shoot.

I’d just about bet that I could load 30.6 and 31.0 and one of those loads would work. Just guessing!

 

[Curious]

What variables can we change and then ask Bart to reshoot the test.

A good start would be to go out and shoot the same test at least twice more and then take an average of the results. There has been a whole load of pissing in this thread over a sample size which in my mind is far too small. Is the test parameter even realistic?

Secondly, how do we know that at 100yds these long for caliber boat-tail bullets are sleeping and so giving their best in terms of accuracy and consistency? I understand the desire for all of us to be able to develop for 1000yds at 100yds but we need to be sure that its even possible if you want to be really competitive. Maybe the same test shot at 300yds as well as 100yds to see if the characteristics of all the groups remain the same would be more beneficial?

Its been interesting so far but boy there are a whole lot of people going 'all in' on the basis of one solitary test, I dont get that?

 

[Trevor60]

At 100 yards ES may be an indicator of the “health” of a load at but has virtually no effect on vertical at this distance.

Fair point, i look forward to your testing at 500... my prediction is 30.6

All the best
Trevor

 

[BartsBullets]

Secondly, how do we know that at 100yds these long for caliber boat-tail bullets are sleeping and so giving their best in terms of accuracy and consistency? I understand the desire for all of us to be able to develop for 1000yds at 100yds but we need to be sure that its even possible if you want to be really competitive. Maybe the same test shot at 300yds as well as 100yds to see if the characteristics of all the groups remain the same would be more beneficial?

Curious,

This is my “opinion” not fact. These are just my thoughts. Are the bullets fully stabilized (asleep) at 100 yards? I say yes. Why? One reason is the group size when the gun looks to be in tune. The other is measuring the size of the bullet hole for individual shots. The paper that these were shot on is the same paper stock that the NBRSA used for years. So we are use to looking at the size and shape of bullet holes. The individual bullet holes on this paper measure approximately .230. Thats the same as I would expect shooting 68 gr bullets at the same target.

Here is some more opinion. I believe that the heavy longer bullets we shoot for long range drift more at 100 yards than then the 68 gr bullets move. It’s just what I see on the target. For a given amount of wind the 105s just move more at 100. I believe (opinion again) the 105 start to shine again as they get out to longer distance because of the high BC and retained velocity.

I’d say those 3 shots were stable.

Bart

 

[Curious]

Curious,

This is my “opinion” not fact. These are just my thoughts. Are the bullets fully stabilized (asleep) at 100 yards? I say yes. Why? One reason is the group size when the gun looks to be in tune. The other is measuring the size of the bullet hole for individual shots. The paper that these were shot on is the same paper stock that the NBRSA used for years. So we are use to looking at the size and shape of bullet holes. The individual bullet holes on this paper measure approximately .230. Thats the same as I would expect shooting 68 gr bullets at the same target.

Here is some more opinion. I believe that the heavy longer bullets we shoot for long range drift more at 100 yards than then the 68 gr bullets move. It’s just what I see on the target. For a given amount of wind the 105s just move more at 100. I believe (opinion again) the 105 start to shine again as they get out to longer distance because of the high BC and retained velocity.

I’d say those 3 shots were stable.

Bart

I get what your saying Bart about seeing good accuracy but in my post I suggested there could be a compromise at 100yds in accuracy and/or consistency?

When I say sleeping I dont mean unstable to the point that the holes appear to be wrong or different, I mean just not fully sleeping to the extent that it takes away all doubt over this area. I dont have the answer myself in this regard, its just a question I have asked myself and have yet to prove conclusively although my gut feeling is testing at 100yds isn't as useful as even 200.

Stretching the test distance out a bit would then rule any question of this aspect out completely.

 

[mgunderson]

We have to be careful not to confuse the natural frequencies with the transient response of the barrel/stock combination. The barrel starts it movement in response to the combustion. The barrel and tuner react, but it is not likely fully developed barrel vibrations.

 

[!Peter!]

We have to be careful not to confuse the natural frequencies with the transient response of the barrel/stock combination.

Might be a bit late for that

 

[Alex Wheeler]

We have to be careful not to confuse the natural frequencies with the transient response of the barrel/stock combination. The barrel starts it movement in response to the combustion. The barrel and tuner react, but it is not likely fully developed barrel vibrations.

I agree the vibrations are not fully developed. That may be a major source of the confusion here. I do not believe the sine wave is a transient response. Heres why, there is accuracy at the tops and bottoms of sine wave targets. Accuracy is coming around the point the barrel stops and changes direction. We can see that in the sine waves so I feel pretty confident that a sine wave really is showing barrel harmonics. Now a gradual trending in the position of the sine I would see how that could be stock as the rifle rotates on its center of gravity. Similar to what we saw in the target without the tuner. That sine wave gradually climbed the target, makes sense it would with less weight on the muzzle. I like that gradual up trend.

 

[urbanrifleman]

Would you guys say that you typically choose the highest node or the one below that to tune too?

The best load, with and without was 30 grains.

 

[Alex Wheeler]

The one where they all converge at 1000 yards!

View attachment 1034359 View attachment 1034360


At least that's how I do it initially for a spot to do other fine tuning.

Tom

Theres no mistaking the right load when you do a 1k ladder I do not want to get side tracked but this is a fine example of positive compensation and how tiny the nodes get at 1k. That 1.xxx" 6 shot group had 18 fps ES.

Which is kind of the reason for this thread. Tom shot a sine wave with that barrel, it did not point him in the right spot. I am really looking for a way to do it closer in than 1k. And I am always looking for ways to promote positive compensation which is another reason for trying to understand what a weight at the muzzle is really doing and if it can be used in a way to help at LR. What I have seen to date steers me away from weight at the muzzle, but I will keep an open mind.

 

[urbanrifleman]

Man. That is cool.