Why I think the Satterlee and Audette Ladder Tests Work and Why-- You Decide!

[jsthntn247]

OCW and Ladders find sweet spots in barrel harmonics. Can't do that with a chronograph. Sometimes a load with a bad ES and SD shoot the smallest at long range.

 

[Veteran]

Yes, shorter bbls probably dont have a lot of harmonics and bullet is gone before it can be effected.

Non magnum calibers below .30 also dont have as much harmonic vibration either and if the bullet timing is pretty close there may not be a big effect for 20 or 24 inch bbl.

 

[Veteran]

OCW and Ladders find sweet spots in barrel harmonics. Can't do that with a chronograph. Sometimes a load with a bad ES and SD shoot the smallest at long range.

The whole subject of Optimum barrel timing (velocity) and the value of the chronograph are intimately tied up with OCW
and Iadders.

1) Read the Chris Long paper referenced in this link below

https://www.longrangehunting.com/th...um-barrel-timing-and-ocw-node-matches.294710/

2) Read about how barrel timing and velocity has a lot to do with which way the barrel is pointing at bullet exit, and
read through Haral's discussion of running a ladder test on a 24 inch bbl. in the links included in this below.

Barrel Harmonics Are A Lot More Important Than You May Think or Know--Here's Proof

First, I have searched for information for about a year and half on this subject. Some of you may know of something really good I've missed, but the best source I have encountered for information on this topic is Al Harral. Who is Al Harral? Al Harral is a retired guy--but one smart...

www.longrangehunting.com

Note: The barrel timing theory in Chris Long's work is very closely related to the barrel timing work and measuring velocity in Harral's work to stay on the left side of the MPC curve.

Harmonics and velocity (therefore pressure) are all inter related.

 

[WildRose]

Yes, shorter bbls probably dont have a lot of harmonics and bullet is gone before it can be effected.

Non magnum calibers below .30 also dont have as much harmonic vibration either and if the bullet timing is pretty close there may not be a big effect for 20 or 24 inch bbl.

There's another hard nut to chew on here.

As a rule the medium and big bore rifles just shoot much better with far less effort than our high velocity smaller bangers which works exactly opposite of that theory in practice but it certainly seems to hold true with everything below about .350.

 

[WildRose]

The whole subject of Optimum barrel timing (velocity) and the value of the chronograph are intimately tied up with OCW
and Iadders.

1) Read the Chris Long paper referenced in this link below

https://www.longrangehunting.com/th...um-barrel-timing-and-ocw-node-matches.294710/

2) Read about how barrel timing and velocity has a lot to do with which way the barrel is pointing at bullet exit, and
read through Haral's discussion of running a ladder test on a 24 inch bbl. in the links included in this below.

Barrel Harmonics Are A Lot More Important Than You May Think or Know--Here's Proof

First, I have searched for information for about a year and half on this subject. Some of you may know of something really good I've missed, but the best source I have encountered for information on this topic is Al Harral. Who is Al Harral? Al Harral is a retired guy--but one smart...

www.longrangehunting.com

Note: The barrel timing theory in Chris Long's work is very closely related to the barrel timing work and measuring velocity in Harral's work to stay on the left side of the MPC curve.

Harmonics and velocity (therefore pressure) are all inter related.

We can complicate this even more talking about seating depth and the effect of that initial impulse as the bullet either slams into the lands or slowly slips in.

Weatherby used a long gradual slope into the lands as a part of the equation to get more speed out of a given cartridge and his rifles routinely were among the most accurate on the market.

 

[Veteran]

There's another hard nut to chew on here.

As a rule the medium and big bore rifles just shoot much better with far less effort than our high velocity smaller bangers which works exactly opposite of that theory in practice but it certainly seems to hold true with everything below about .350.

I think it just depends on the rifle and the build quality as well as caliber. A .270 with no glass bedding, and a long sporter bbl
may shoot worse than a heavy custom rifle free floated, bolt face trued, Big heavy bull barrel in large caliber, but all things being equal, in my experience the sheer magnitude of the explosion in large cal magnums or say a .50 will cause not only more recoil but much worse harmonic vibrations that have to be tuned out. Your experience depending on the rifle and its build qualities may be different.

 

[WildRose]

I think it just depends on the rifle and the build quality as well as caliber. A .270 with no glass bedding, and a long sporter bbl
may shoot worse than a heavy custom rifle free floated, bolt face trued, Big heavy bull barrel in large caliber, but all things being equal, in my experience the sheer magnitude of the explosion in large cal magnums or say a .50 will cause not only more recoil but much worse harmonic vibrations that have to be tuned out. Your experience depending on the rifle and its build qualities may be different.

There's a good chance that the heavier barrels limit that effect. We tend to use very heavy barrels on big boomers for both the sake of safety and to help manage/reduce recoil.

Some of the doubles chambered in the big African magnums are going to weigh upwards of 18lbs and of course nobody shoots a lightweight .375 Cheytac or 50BMG. I'd also posit that with those insanely accurate double rifles the fact there are two barrels soldered together provides a whole lot more stiffness than the same weight barrel in a single would have.

There's at least one exception to every rule and while I'm generally convinced that barrel harmonics play a big role I recognize that in those larger bores that doesn't seem to be a weighty a factor.

 

[Veteran]

There's a good chance that the heavier barrels limit that effect. We tend to use very heavy barrels on big boomers for both the sake of safety and to help manage/reduce recoil.

Some of the doubles chambered in the big African magnums are going to weigh upwards of 18lbs and of course nobody shoots a lightweight .375 Cheytac or 50BMG. I'd also posit that with those insanely accurate double rifles the fact there are two barrels soldered together provides a whole lot more stiffness than the same weight barrel in a single would have.

There's at least one exception to every rule and while I'm generally convinced that barrel harmonics play a big role I recognize that in those larger bores that doesn't seem to be a weighty a factor.

Yep a double barrel oughta cut the harmonics in half.....

 

[Veteran]

Yep a double barrel oughta cut the harmonics in half.....

Unless ya accidently shoot both barrels at the same time....

 

[WildRose]

Unless ya accidently shoot both barrels at the same time....

Sadly I've done that.

My dad had an Ithaca 280 side by side that for no known reason would occasionally fire off both barrels. Even in a 20g that is an eye opener.

That model had inertial cocking so that may have been the problem but we never quite figured it out. It probably hasn't been fired now in over 30 years.

 

[jsthntn247]

Most top shooters in FTR don't go heavier than a heavy Palma. The reason is larger node windows because the barrel has more whip. Alex Wheeler has done more research on the subject than anyone.

 

[mulie]

OK "Veteran" enough interpreting what is in the book. It is OK to let people read. Nothing wrong in letting people read and discover on their own. VERY good book, I took a gunsmith class from Speedy Gonzales it was highly recommended reading by him for class. Saved a large amount of time in understanding the bigger why and what is needed picture for accuracy with good data supporting it. So let them learn on their own. KIDDING good thread.

As I have been thinking about how the whole science of internal ballistics includes barrel harmonics, it occurs to me that accuracy and small groups must always be related to bullet in barrel timing and position of the muzzle at bullet exit.

AND HOW IS THIS consistency CREATED beginning with the seed and what drives it for how long to point of exit.

 

[aschler]

I looked this book up. Its 305 pages and costs $160 used.....$2 to 300 new......but I found a free download and downloaded it. I am very interested to read it. Thank you for pointing it out.

Wow, that's crazy.