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Is your neck too thin...
Bullet retention in a cartridge is very important in that it has the same press fit in all re-loads to achieve the same ballistics each time. As press fit is reduced the friction is reduced, and up goes the ballistic speed of your bullet. I believe that all re-loaders should check the outer diameter of the cartridge, and categorize them into groups for consistency. I prefer not to load brass that has stretched more then .002 in thickness. This would compute to .004 on the diameter. Most new cartridge brass measures .015 in thickness, but can vary a bit for larger bullets. This is why factory ammo although not better can have more stable ballistics then re-loading ammo that is not staged by neck size. If you load different sized neck brass you cannot expect the same results at the target. Sort, and don't load thin brass for safety!

No thin necks...RIGHT!
Larry243
 
I'm curious - what basis do you conclude no thin necks? Most short range competitive shooters turn necks down to .008 for tight neck chambers.
 
The best answer is...
The thicker the metal, the tighter th retention and better consistency in multiple rounds. As brass thins it also becomes brittle and looses it't retention value. It also will no longer fit the chamber correctly for re-loaders.
Cartridge Brass that is C26000 or sometimes known as B36 is annealed for manufacturing capability and draw qualities for tooling. If it were 1/4 hard it would break, split, crack, or blowout during forming. The annealing process of old fired brass only helps minimal at best.... If the base metal stretches to much it's done anyway!

The hand gun was manufactured with a pre-sized chamber and to fit a specific diameter cartridge. If the bullet Jump and cartridge diameter is excessive, what do you then get out the other end.... RIGHT
Larry243
 
My neck is too thin? What neck? I look more like that little robot on the Star Wars movie.

I was with you right till you said factory ammo has more stable ballistics. That sure hasn't been my experience. I agree, consistency is paramount for accuracy reloading and anything you can do to keep constants in the equation is a good thing. I only reload for accuracy of that kind in my 22-250 and .243 though. Eveything else drops dead if I can hit the inside diameter of a pie plate.
 
Neck Thickness, hardness and length all come into play when one considers the tension applied to the bullet, as well as dry lube, carbon or completely clean neck IDs.

And of course, how far down you size the length and od of the neck itself.
 
My neck is too thin? What neck? I look more like that little robot on the Star Wars movie.

I was with you right till you said factory ammo has more stable ballistics. That sure hasn't been my experience. I agree, consistency is paramount for accuracy reloading and anything you can do to keep constants in the equation is a good thing. I only reload for accuracy of that kind in my 22-250 and .243 though. Eveything else drops dead if I can hit the inside diameter of a pie plate.

No NO No!
I am only talking ft/per/sec speed. They can not and do not shot as straight as Hand-Loads for sure. I have used my Chronograph many times on factory ammo, and the bullet speed is pretty consistent with factory junk, especially using Hornady products. I also punch paper every Wednesday with my .243 & 6.5 Creedmoor with 58A-Max, 95SST, and 105 BTHP, and 129 with the Creedmoor at 100yds. I fine tune my ballistics with powder, and maintain the Ogive very precisely, and chart all my shooting for accuracy. My challenges are to take those 3 bullets and cover 1-1/2" at 100 yds with a sporting barrel. I do want the ballistics up to what they are suppose to be, and that is why I play with a couple different powders. Sorry if I mis lead you about accuracy. Bullet retention consistency is one I am death on.... I shoot paper for accuracy but hunt for Hair!....:)
Thank's
Larry243
 
Neck Thickness, hardness and length all come into play when one considers the tension applied to the bullet, as well as dry lube, carbon or completely clean neck IDs.

And of course, how far down you size the length and od of the neck itself.

But of course,
No one sizes the neck with tapper, what would be the purpose of that. You loose all the bullet retention, and back pressure needed for correct ballistics. Clean and sized necks are all about retention... That is why we do it!
Right?
 
But of course,
No one sizes the neck with tapper, what would be the purpose of that. You loose all the bullet retention, and back pressure needed for correct ballistics. Clean and sized necks are all about retention... That is why we do it!
Right?
Some people neck size only. The bushing does not go all the way to the shoulder. This is what I was referring to.
 
Got it!
The length of the neck land inside is what determines the surface contact of a bullet. If you shorten or lengthen the contact surface it would effect the amount of bullet retention...Right? I have seen cartridge stretch so bad that only about .100 land is all that is touching the bullet because of brass thinning. This is never correctable... The brass is Toast! The sizing bushing will only control the OD, not the ID. If the trim length is correct, and the metal thickness is still stable then the ID and OD should conform to a straight size. Cartridge Brass is normally .015 thick so if it stretches .002, that is .004 on the diameter...NOT GOOD!
What-Cha-Think ?
Larry243
 
Got it!
The length of the neck land inside is what determines the surface contact of a bullet. If you shorten or lengthen the contact surface it would effect the amount of bullet retention...Right? I have seen cartridge stretch so bad that only about .100 land is all that is touching the bullet because of brass thinning. This is never correctable... The brass is Toast! The sizing bushing will only control the OD, not the ID. If the trim length is correct, and the metal thickness is still stable then the ID and OD should conform to a straight size. Cartridge Brass is normally .015 thick so if it stretches .002, that is .004 on the diameter...NOT GOOD!
What-Cha-Think ?
Larry243
I think you're over complicating it. :D

Neck sizing definitely sizes the ID.

Will it be 100% concentric? Not unless the necks have minimal to no runout. However, the ID will definitely be sized due to the neck being squeezed down.

The surface of the ID will be irregular again, unless it is perfect to begin with.

I rarely neck size only anymore, but it works well if the other brass prep has been done such as sorting for neck thickness runout, and or turning the necks.
 
Last Edited:
We are pretty well in agreement for sure. When Cartridge Brass stretches, it has irregular thickness through it's length. The only way to correct it, is to reduce the Diameter enough that it can be reamed back to straight wall size. The problem with that is that is steals from the OD that is also critical for the breach fit. If it flop's around like a fish out of water and is not concentric, then what comes out the other end becomes Junk in, Junk out . I very rarely reload brass more then two times due to brittleness issues anyway. Annealing rarely works either for reforming to get good quality brass cartridges again anyway.
Like you, I truly believe in sorting for size and run-out...
Larry243
 
By nature of case manufacturing, case wall is not concentric.
Resizing a case doesn't change case wall thickness.
Press a case into a die, squeeze it down a little.
Pull it out past the neck sizing ball.
The neck I.D. is a skosh smaller than the bullet O.D.
Neck runout is not concentric because wall thickness is not the same all around.
Bullet launch into lands is off.
Solution: After re-sizing, turn outside of the neck.
Completed cartridge is locked into chamber with the bullet aligned with the center of launch
 
By nature of case manufacturing, case wall is not concentric.
Resizing a case doesn't change case wall thickness.
Press a case into a die, squeeze it down a little.
Pull it out past the neck sizing ball.
The neck I.D. is a skosh smaller than the bullet O.D.
Neck runout is not concentric because wall thickness is not the same all around.
Bullet launch into lands is off.
Solution: After re-sizing, turn outside of the neck.
Completed cartridge is locked into chamber with the bullet aligned with the center of launch

Please re-think this, and get back to me....
Once materials have been stretched thin, you can either reform the OD,or the ID...
But one is going to be Toast.... you can never regrow the .015 thickness ever again. Changing the consentricity has nothing to do with thickness.

Thank's

 
These groups were shot with necks turned down to .0082 and I typically shoot each case about 14 times before I start getting a click upon extraction. Cases are still useable but I start fresh with new brass after 14 reloads because the click comes with a heavier bolt lift and that upsets my aiming. 6 PPC Nov 2017.jpg
 

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