Published petloads

[BJung]

My last discovered petload was for my Model 66 .357 using 158gr JHP and Blue Dot. My two best groups were 10.5gr and 11.5gr, exactly the same as what was recommended by another Reloader online.

How many have found someone's suggested petload the ideal petload for their handgun too?

And, is there an ideal MV for a particular weight bullet shot through a certain handgun? If so, I person can shoot a string of loads through a chronograph and find his petload quicker than comparing groups.

That brings up Nodes. While the ladder test is standard for rifles, has anyone used it with a chronograph? Then, like a rifle make a string of loads with the same powder weight but different OAL and find the optimum pet load. If so, a Reloader can bring prepped casing and a hand press to the range and find a petload much sooner.

 

[Unclenick]

The reason velocities don't provide fixed accuracy nodes is different powders achieve particular velocities with different barrel times—a fast powder achieves a certain velocity in a shorter barrel time than a slow powder does—and, usually, it is a certain barrel time that you want to achieve to stay on a node because that affects where in the barrel's vibration or deflection phase the bullet exits.

 

[gwpercle]

357 magnum
Lyman # 358156 155 gr. SWC GC
7.5 grains Unique
Skeeter Skelton load

41 Magnum
NOE 412- 237- SWC (Keith) PB
7.5 grains Unique
From Elmer Keith

These two turned out to be favorites... I have used them for 40+ years and have not come across any more accurate ...these are general purpose , pleasant shooting field loads not close to maximum .

 

[Bart B.]

If you're serious about handgun accuracy, get a Ransom rest.

https://ransomrest.com/

Us humans cannot hold, aim then fire them repeatable enough to assess handloads accuracy to the nth degree.

 

[hounddawg]

If you like playing with different loads pick up a copy of KenWater's book Pet Loads. A lot of great load recipes and a lot of just plain entertaining reading in that book. Four separate segments on the .357. Anyone remember using Norma R123 powder ?

 

[BJung]

Ken Waters' Petload book

I have that book.

Whenever I go to a magazine stand, I look for Handloader first.

 

[BJung]

Cast Bullet Book

Besides Lyman's book, is there a cast bullet book equivalent to Ken Waters' book?

 

[Bart B.]

The reason velocities don't provide fixed accuracy nodes is different powders achieve particular velocities with different barrel times—a fast powder achieves a certain velocity in a shorter barrel time than a slow powder does—and, usually, it is a certain barrel time that you want to achieve to stay on a node because that affects where in the barrel's vibration or deflection phase the bullet exits.

I like the term "deflection phase" describing the handgun barrel's bore axis (line of fire) moving up as the gun recoils during barrel time. This is why the front sight reference is higher above the bore axis than the rear sight reference. The line of sight is above the line of fire when the cartridge primer fires.

I've never seen any handgun barrel vibration diagrams. If ever calculated, they would be educational. Their resonant and harmonic frequencies will be several times higher than those of rifle barrels. It's easy to see using a collimator in the barrel showing where it points below the LOS.

Depending on how ones arm is set, their grip on the gun and muscle tone, where the muzzle points at bullet exit relative to LOS when the primer fires may not be repeatable across several shots. This is why 22 rimfire free pistol's bore axis is aligned close to the shooting arm axis so there's minimal LOF change to LOS during barrel time.

 

[BJung]

Pitchfork

Unclenick,

An analogy to what you're saying is the pitchfork, yes?

So, If I use the same powder, I create the same node. If someone finds a petload with their Model 66 barrel and revolver, with the way guns are massed produced, the nodes using the same petload should be the same or very close

 

[BJung]

Vocabulary correction

I mean tuning fork

 

[44 AMP]

the nodes using the same petload should be the same or very close

Possibly. The key here is "should be". All guns are made the same, so all should be the same, right?

Not quite.

Everything we make has +/- tolerances. Everything. I think the phrase currently popular is "stacking tolerances". Tiny little variations each within its acceptable range can "add up". And they can do it in different ways.

The best way to visualize it is the "bell curve". Some combinations are at one end of the curve some at the other end. Most things fall somewhere in the middle, which is why reloading data is useful as guidelines.

The "sweet spot" or accuracy node, or what ever you call it in your gun, with its barrel, and your combination of components can be different from another gun and its ammo. Even when you duplicate their ammo to the greatest extent possible, your results MIGHT be different then theirs.

Most of the time, it will be close, somewhere in that middle of the curve. But it is possible you could be at either end, and this is not something anyone can know, until you shoot and get results.

So, yes, your results might be the same as theirs, or very close, but its not an absolutely will be, its a could be, and a probably will be. Expect something close, just be aware it might not be.

Good Luck!

 

[Bart B.]

Ladder tests with rifles are done with barrels vibrating at frequencies about one tenth that of handgun barrels. Powder charges are adjusted so bullets leave on the muzzle axis upswing so slower ones leave at higher angles than faster ones. One's dealing with sub MOA changes. Resonant frequency of a typical rifle barrel is several dozen cycles per second, the harmonic frequency its muzzle axis vibrates at is several times higher. Handgun barrels vibrate at frequencies several times higher than rifle barrels.

Pistol and revolver barrels need to test no worse than 2 MOA before any ladder testing and charge changes might be worthwhile.

Accuracy claims based on smallest groups fired are hard to duplicate.