I'm using lapua brass and I forget the reamer specs, but it's not a tight neck. I'm not really interested in neck turning. At least not in this stage of my life.
Adjusting neck tension when using mandrels
- Thread starter goosepilot
- Start date
He sold the dies before I bought the rifle. The rifle only had 50 some rounds through it, but was the 3rd one from the gunsmith. I now have a wilson bushing sizer and micrometer seater. Just a matter of a little experimenting in the next week
The idea behind the mandrel is to make the brass concentric for bullet seating. Any irregularities go to the outside. By turning necks, you have a concentric neck wall thickness to do anything you want to, with any bushing or mandrel combination you can come up with. Imo, you are leaving a lot on the table by not turning the necks concentric before you do all the experimenting. Just my take on it. Good shooting to you.
Paul
AlNyhus
Silver $$ Contributor
Same as the SR competitors, Jim.
-AlAlNyhus
Silver $$ Contributor
Absolutely correct, Paul.
If necks are so eccentric that using a mandrel is needed to address bullet concentricty, the necks need to be touched up by a light turning. Often, just enough to remove the eccentric...around 75% of the outside neck...is all that's needed to be done.
Good shootin'
-AlMikeRu
Gold $$ Contributor
21st century will make mandrels down to 238 or so. I bushing down to about 237-238 then mandrel up with 240-242 to get whatever seating pressure that works best , using Wilson seater, K&M arbor press and guage.
DLT
Silver $$ Contributor
Never did on any of my brass. 223 and 22/250
ELR LVR
Silver $$ Contributor
I would not think you would get more neck tension either
I ran an experiment last night to proof my theory on this
Posted here:
Does the bullet slide out of the neck or does the neck open to release it?
Primer fires, some powder burns, making gas. The gas pushes the remaining 2/3 powder forward, against the bullets base. It continues to burn till it consumed. Burn rate makes a difference. Slow powders may exit the muzzle, unburnt. https://discover.dtic.mil/
forum.accurateshooter.com
I read your post which you linked to, you've done your homework
.I'll throw in another angle which crossed my mind. Measuring the I.D. of necks compressed by different diameter bushings, after seating and bullet pulling, as a proxy for neck tension tells one story. The other story, possibly, is we don't know how much effort it took to pull the bullets. Is it possible for the pulled necks to revert to the same I.D. even if they exert different radial forces on the bullet, i.e. have different neck tensions? I think it's possible depending on where the necks are on the elasticity curve.
None of it probably matters on the target, just fun stuff to ruminate. I made a bullet pulling force gage a ways back, I'll dust it off and see if there's any low hanging fruit.
Coyotefurharvester
Silver $$ Contributor
I do most of my brass prep per #2. Mostly hunting, prairie dog loading. Both gas and bolt guns. Mandrels I use (regardless of caliber/cartridge) are 0.002- 0.003 under bullet dia. I use bushings that size the brass down so the mandrel expands the neck 0.002-0.003. Does not seem to work the brass hard and is enough to ensure neck is round(gas guns are hard on necks). My 20p(gas gun) does require a slight crimp, even with mandrel more than 0.002 under bullet diameter, or the bullet coal shortens a few thou after loading of the mag a couple times in cold weather.
Edd
Gold $$ Contributor
I would buy a pin gauge and make my own.
ELR LVR
Silver $$ Contributor
What I am suggesting is there is no further radial forces by neck sizing down furtherI read your post which you linked to, you've done your homework
I'll throw in another angle which crossed my mind. Measuring the I.D. of necks compressed by different diameter bushings, after seating and bullet pulling, as a proxy for neck tension tells one story. The other story, possibly, is we don't know how much effort it took to pull the bullets. Is it possible for the pulled necks to revert to the same I.D. even if they exert different radial forces on the bullet, i.e. have different neck tensions? I think it's possible depending on where the necks are on the elasticity curve.
None of it probably matters on the target, just fun stuff to ruminate. I made a bullet pulling force gage a ways back, I'll dust it off and see if there's any low hanging fruit.
After being stretched out the same amount
---Unless the brass is thicker
To quote WIld Bill IV who explained further after my post
"Cartridge brass can be compressed 0.0005" and will recoil back that 0.0005" without being reformed or reshaped!!! Upon reshaping (reforming) the brass, the grains and boundaries of the grains under high stresses and strains!! "
Quote from post 100
Does the bullet slide out of the neck or does the neck open to release it?
Primer fires, some powder burns, making gas. The gas pushes the remaining 2/3 powder forward, against the bullets base. It continues to burn till it consumed. Burn rate makes a difference. Slow powders may exit the muzzle, unburnt. https://discover.dtic.mil/
forum.accurateshooter.com
The reforming --- changes the grains and boundaries to reform a new shape
it no longer will retain it's old shape
The new shape is your bullet diameter
----------------------------------------------------
I'd be interested to see your findings with your pulling force gauge
necks with .009"-.012" neck thickness
then with necks thicker than .012"
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I'd be willing to suggest that once at .015 such as winmag brass, things change and there would be more spring back with smaller neck sized brass
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if you have any coated bullets, I'd try those too
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What I used the pull gage for at the time was to accurately determine peak force needed to pull a bullet in order to compare that to the peak force required to seat the bullet; pulling force was about 2/3 the seating seating force. Knowing the cross-sectional area of the bullet, it was easy enough to calculate the pressure require inside the case to pop the bullet out. When compared to the maximum pressure for 6.5 Creedmoor, 63000-ish psi, it was negligible and not readily identifiable on a QuickLoad pressure graph where projectile travel is shown on the X-axis. IIRC, it would take about 550 psi to pop a bullet from the cartridge.
This led me to believe that while there are many good reasons to have neck tension, such as ensuring cartridges stay intact bouncing around in a box, or getting banged around in a magazine etc., and keeping the bullet pointed coaxially to the throat and rifling, I have my doubts that it has much effect on building the pressure curve.
This led me to believe that while there are many good reasons to have neck tension, such as ensuring cartridges stay intact bouncing around in a box, or getting banged around in a magazine etc., and keeping the bullet pointed coaxially to the throat and rifling, I have my doubts that it has much effect on building the pressure curve.
ELR LVR
Silver $$ Contributor
Precisely, and my thoughts as well.
I just posted in another thread...it's more of a placebo effect
Thank you for your insight
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ELR LVR
Silver $$ Contributor
Another member here ( 46and2) did an experiment as I did
But also measured the pull force required to pull the bullets after seating
His results were that ...
it took the same amount of force to pull a bullet as it did to seat it
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posted in Post 79 here:
But also measured the pull force required to pull the bullets after seating
His results were that ...
it took the same amount of force to pull a bullet as it did to seat it
--------------------------
posted in Post 79 here:
Does the bullet slide out of the neck or does the neck open to release it?
I never, or possibly very rarely, ever see the complete absence of blow by before bullet exit. I do assume the bullet seals the barrel, and a video where gas is escaping AS the bullets exits would point to some serious inaccuracy questions. If we view a cartridge and its neck as little...
forum.accurateshooter.com
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ELR LVR
Silver $$ Contributor
Are the 2 differences we're looking at
Bullet Seating force
or
Bullet Pulling force
Because, seating force could be triple, of the force needed to cause the bullet to exit and does not necessarily correlate with one another
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As I've mentioned seating force to insert a bullet into a smaller orifice stands to reason will be higher
but once inside the neck, there should not be much difference to pull the bullet out of each case
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I am open to correction if someone finds different results but look a couple posts above as another guy did that test which I posted his results
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Maybe what I'll try later is
take a .224 case and size it down to .17
take a second and size it down to .221
then test the differences of force required to PULL the bullet
Seating force is not relative here to what we're trying to test or accomplish
--------------------------
Only pulling force to get the bullet out is
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