Inside the case neck polishing/tuning?

[Beiruty]

A) The correct case neck tension
B) The inside of the case neck concentricity
C) The inside of the case neck smoothness

are all desirable features from the time when ignition starts till the time when fully in the bore of the barrel. That time is around 0.1ms or 100 micro second.

Questions:
1) Is the initial pressure of the LR primer (3600 psi) enough to push bullet the bullet fully into the bore?
2) Is the initial pressure of the LR Magnum primer (5200 psi) enough to push bullet the bullet fully into the bore?

If either of 1) or 2) are true, then primers selection has the most important impact on the bullet launch sequence in the first 0.1ms of its time in the barrel.

3) Is more case neck tension or less tension desirable?
4) Is the inside of the case neck smoothness more important the case neck tension
5) Is there a test for A) and B) vs virgin cases?

The floor is open for polite debate of the issues at hand.

 

[RickyK]

Why debate , just test for yourself !!!

 

[K22]

With all due respect, I think, except for question number 3, these are theoretical questions which, in my humble opinion have limited practical value. However, that's fine - it might be fun to debate these issues and that is part of what this site I believe can be used for.

With regards to neck tension, I believe consistency is more important than the amount. However, I'm not a benchrest shooter seeking ultimate precision - I'll then those guys chime in on that aspect of reloading.

I assume these questions are directed at load development.

For me, the first step is finding a bullet that will meet my needs and is compatible with the twist rate of the rifle. I've found that this is the most critical aspect of load development.

Second is selecting a powder that is compatible with the caliber and the bullet weight chosen. This is a little easier than the bullet issue since with most calibers there is known and proven powders that word with that caliber and bullet.

From there is a matter of finding the optimum powder charge, which can make a significant difference.

After those first three steps, comes refinement, seating depth and primer selection. Rarely have I've seen these make a significant difference, but they can. Of course, uniform case prep plays a roll. But at least in my experience, the first three are the key issues in load development.

 

[mikecr]

1) and 2) doesn't matter. We use burning powder to expand necks, releasing and pushing bullets.
3) Least tension the load likes is desirable, as lower tension = lower variance of tension.
4) doesn't matter for same reason as 1) & 2).
5) unintelligible

We don't push bullets from necks. Instead, bullets are released from necks.

 

[FeMan]

In response to #1 and #2, I have loaded rounds with no powder several times and never even had a bullet move in the case as a result of setting off the primer. It just blackens the boat tail.

In response the other three questions, it depends on the rifle/load and is never a constant. You need to test and recheck these periodically. IME, even once you find "the" recipe in a rifle, it will eventually change with weather, round count, brass hardening, etc.

 

[Beiruty]

1) and 2) doesn't matter. We use burning powder to expand necks, releasing and pushing bullets.
3) Least tension the load likes is desirable, as lower tension = lower variance of tension.
4) doesn't matter for same reason as 1) & 2).
5) unintelligible

We don't push bullets from necks. Instead, bullets are released from necks.

5) Turning the inside of the case neck vs virgin case accuracy/MV SD tests

 

[AlNyhus]

Most of this can't be generalized or covered with a blanket statement as 'fact'.

A good example is the question about primers pushing a bullet fully into the bore. One style of leade angle may allow it to happen. But change the leade, freebore diameter, bullet profile, etc. and the result will be different.

I am a believer in perfectly round inner case necks for more consistent neck tension.

Things like neck tension (more or less) being 'better or worse' is simply impossible to say empirically. Much of this depends on not only the individual components used but also the characteristics of different powders. Not to mention what an individual bullet profile likes.

In the end, it's nice to theorize about all this but you have to treat each barrel individually.

Good shootin' -Al

"Not everything that can be counted, counts. And not everything that counts, can be counted." -Albert Einstein

 

[Beiruty]

In response to #1 and #2, I have loaded rounds with no powder several times and never even had a bullet move in the case as a result of setting off the primer. It just blackens the boat tail.

In response the other three questions, it depends on the rifle/load and is never a constant. You need to test and recheck these periodically. IME, even once you find "the" recipe in a rifle, it will eventually change with weather, round count, brass hardening, etc.

Thank you for sharing your info.

 

[drop_point]

Wouldn't 1 & 2 both be dependent on neck tension? If that is true, wouldn't there be multiple situations which modifying variables would yield acceptable results?

 

[6BRA]

As far as primers starting the bullet rolling, take a look at the progression of modern day blacknpowder rifles...209 primers were discovered to be a bit much for them if I recall correctly.....I would think some of the same may apply

 

[jackieschmidt]

Why debate , just test for yourself !!!

^^^^^^^
but then, if we don’t debate, we will never discover how many angels can dance on the head of a pin.

 

[ebb]

If loaded even close to the lands the powder is burning big time before the base of the bullet has left the neck. As i envision this none of it means anything in the whole scheme of things required to get the bullet fully into the bore. My understanding of how it works, no idea if this is really what happens.

 

[BORGY76]

Why debate , just test for yourself !!!

No debate/discussion, just think where the world would be without either.

 

[Drolds72]

Just forget to put powder in a case, and you will find the answer to 1&2 real quick! Bring a cleaning rod without a jag for this experiment.

 

[mikecr]

No, he wouldn't find a true answer..
A truth passes all tests

 

[357Mag]

A) The correct case neck tension
B) The inside of the case neck concentricity
C) The inside of the case neck smoothness

are all desirable features from the time when ignition starts till the time when fully in the bore of the barrel. That time is around 0.1ms or 100 micro second.

Questions:
1) Is the initial pressure of the LR primer (3600 psi) enough to push bullet the bullet fully into the bore?
2) Is the initial pressure of the LR Magnum primer (5200 psi) enough to push bullet the bullet fully into the bore?

If either of 1) or 2) are true, then primers selection has the most important impact on the bullet launch sequence in the first 0.1ms of its time in the barrel.

3) Is more case neck tension or less tension desirable?
4) Is the inside of the case neck smoothness more important the case neck tension
5) Is there a test for A) and B) vs virgin cases?

The floor is open for polite debate of the issues at hand.

Beiruty -

Howdy !

Well...... I dunno....

I have done load work and experimentation using the .35 Remington case " wildcatted " to have no neck.
In other words..... " .35 Remngton Neckless ". The wildcat has a shoulder, just no neck.

I had in-mind to shoot " patched " bullets, and found a .45" cal saboted muzzle loader round that featured a
.350" calibre tipped spitzer boat tail bullet.

My idea :
- Pull the .350" cal swaged lead SPBT from the plastic sabots. Max diam @ top of boat tail = .308"

- Patch using self-sticking "DYMO" label maker tape. The tapes' thickness allowed for great gas sealing inside the .358" groove diam barrel of my Marlin M-336 XLR test rifle ( 12 groove "Ballard " rifling ).

- Use an existing die to form an extended shoulder on the ( neckless ) case. Utilize a final case' mouth ID that would accomodate the max .308" diam of the upper boat tail. Ultimately, the face of the case' " mouth "
is a limited diamter flat surface ring.

- Use the overhang of the bullet' body over the rebated boat tail as the interface between the bullet and the neckless case's flat case mouth ring.

- The leade in the Marlin in conjunction w/ the length of the 195gr SPBT allowed me to breech seat the bullet. The entire round became integrated by operating the lever, which introduced the BT of the bullet into
the case " mouth; sorta " Schuetzen " style. The tapered BT basically self guiding into the case' mouth.
*** The bullet's contact w/ the rifling allows the bullet to be pushed back fully against the front face of the case' " mouth ", when the gun is in battery. ***

The rifle / .35" cal neckless wildcat accuracy would have been more than accurate for a task such as killing a deer @ 100yd. My SR4759 powder charges were on the increase as I cautiously proceeded in my testing.... right up to the point when I ran out of the .350" cal SPBTs. I have no doubt that loads for this wildcat could have been developed w/ sufficient energy to humanely kill a deer @ an example 100yd.

Not making any sensational claims. The experimental wildcat was just that. Wanted to see what's possible.

My point:
In certain circumstances and under certain conditions ( such as the wildcat above ), things like neck wall thickness, neck wall concentricity, amount of neck sizing performed, bullet release from contact inside a brass case' neck, loaded round neck clearance in the chamber et al; can even be rendered non factors.

But the rest of the time....you'll need to test, in-order to ultimately prove the combniation and configuration that shoots best for you.


With regards,
357Mag

 

[Beiruty]

Beiruty -

Howdy !

Well...... I dunno....

I have done load work and experimentation using the .35 Remington case " wildcatted " to have no neck.
In other words..... " .35 Remngton Neckless ". The wildcat has a shoulder, just no neck.

I had in-mind to shoot " patched " bullets, and found a .45" cal saboted muzzle loader round that featured a
.350" calibre tipped spitzer boat tail bullet.

My idea :
- Pull the .350" cal swaged lead SPBT from the plastic sabots. Max diam @ top of boat tail = .308"

- Patch using self-sticking "DYMO" label maker tape. The tapes' thickness allowed for great gas sealing inside the .358" groove diam barrel of my Marlin M-336 XLR test rifle ( 12 groove "Ballard " rifling ).

- Use an existing die to form an extended shoulder on the ( neckless ) case. Utilize a final case' mouth ID that would accomodate the max .308" diam of the upper boat tail. Ultimately, the face of the case' " mouth "
is a limited diamter flat surface ring.

- Use the overhang of the bullet' body over the rebated boat tail as the interface between the bullet and the neckless case's flat case mouth ring.

- The leade in the Marlin in conjunction w/ the length of the 195gr SPBT allowed me to breech seat the bullet. The entire round became integrated by operating the lever, which introduced the BT of the bullet into
the case " mouth; sorta " Schuetzen " style. The tapered BT basically self guiding into the case' mouth.
*** The bullet's contact w/ the rifling allows the bullet to be pushed back fully against the front face of the case' " mouth ", when the gun is in battery. ***

The rifle / .35" cal neckless wildcat accuracy would have been more than accurate for a task such as killing a deer @ 100yd. My SR4759 powder charges were on the increase as I cautiously proceeded in my testing.... right up to the point when I ran out of the .350" cal SPBTs. I have no doubt that loads for this wildcat could have been developed w/ sufficient energy to humanely kill a deer @ an example 100yd.

Not making any sensational claims. The experimental wildcat was just that. Wanted to see what's possible.

My point:
In certain circumstances and under certain conditions ( such as the wildcat above ), things like neck wall thickness, neck wall concentricity, amount of neck sizing performed, bullet release from contact inside a brass case' neck, loaded round neck clearance in the chamber et al; can even be rendered non factors.

But the rest of the time....you'll need to test, in-order to ultimately prove the combniation and configuration that shoots best for you.


With regards,
357Mag

Excellent info

 

[Beiruty]

The old school techniques for accuracy
1) Bullet touching the rifling or jammed by 0.00x"
2) Minimum total runnout
3) Dry lubed inside case neck to reduce bullet jacket from being damaged while being seating and minimizing the tension variation while the bullet being released.
4) Consistent BTOG
All those factors were intended to keep bullet staying concentric while leaving the the bullet case neck and fully into the bore.

The new VLD/LRHT bullets allowed the bullet to self-center while fully into the bore.
A) Less tension on the bullet would result in allowing the bullet to move at very low pressure
B) Higher tension on the bullet would result in allowing the case to seal the chamber faster before the bullet started to move under higher pressure

 

[D-4297]

This is only a "relative" question , as part of the initial parameters laid out by the OP . Most shooters are aware that having powder residual in the neck of a fired case aids seating and "release" of the bullet when the next round is fired . Accepting that ; Why would "polishing" the inside of the neck be of any benefit , as that would "reduce" the amount of powder build-up , due to the brass not having ability to "grab" powder molecules ? So ; would polishing actually be a benefit , or a detriment ?

 

[mgunderson]

Are we able to separate neck tension from bullet jam forces? Definitely some combustion consistency benefits from building pressure before the bullet moves. Interesting thought exercise.