Neck Tension vs Bullet Seating & Release Pressure - Lessons Learned

[Mikecr]

My neck sizing standard centers on consistent bullet release.
That's it. Everything else takes care of itself.
I don't need excess grip, excess clearance, nor excess alignment themes.
This is my typical, as merely eyeballed & setup good enough for fire forming/testing:

Many times I just end up sticking with a setting like this. No reason to change it.
Now I could change it. I could size another 1/16" here,, still be on bearing,, a bit more tension/MV.
But here's the thing; I have plenty of frictional and static grip. The necks are not over-worked. This is so easy to EXACTLY reproduce, over & over & over (unlimited reloads).

In contrast, I discourage ANYONE from EVER doing THIS.
A FL sized neck:

The tension here is way higher, and you can bet it's variance is as well.
You have donut area, which is always inconsistent, brought into tension.
And you have unsized neck binding against the bearing-base junction.
No doubt over time this will push the bullet outward, changing CBTO, and changing tension.
Speaking of CBTO, good luck fighting to get each round at desired while using your bullets for this kind of neck expansion.
These necks will not likely produce low loaded runout either.
There is nothing 'good' in this plan.
My vote for world's ugliest neck:

 

[243winxb]

If the bushing has to size down fired brass, more then .008" its not recommended by Redding.
My factory chamber likes about 1/2 of the neck sized. This helps alignment of rounds in the chamber.

No expander used.

 

[Mike Matteson]

If the bushing has to size down fired brass, more then .008" its not recommended by Redding.
My factory chamber likes about 1/2 of the neck sized. This helps alignment of rounds in the chamber.

I using Redding bushing dies for reduce the neck from ID .282 to .242. It take 4 reduction to achieve that. After 2nd reduction I anneal again. to complete the process. I start something like what you have here with 308NM rifle. I was losing case with separation at the base in about 3 firing with a FL die. At about the same time I change to a 300WM Neck die. The 308 NM neck is longer and the shoulder is shorter. In using the 300WM achieved what you are showing in the picture and Mikecr is showing. No donut either. That stop the case separation at the same time. I would lose them to primer pocket getting to large after that. Thanks to both of you showing your cases. We are on the same page mostly. I cut my necks for even thickness in the start of working over a case. I have no problem sizing to .241 ID with the necks for the 6mm/280AI chamber. I will set up and do this for all my different rifles. My sons too. Redding is going to love me.

No expander used.

 

[Muddyboots]

One heck of an experiment! Couple minor questions.

When the bullets were examined after seating and then releasing the bullets, I was surprised to see that there was no damage or even scratches left on the bullet bases or jackets no matter what bushing and NT was used. This was true for both the Hornady (see image) and AH bullets. This can likely be attributed in large part to the use of a VLD chamfer tool, brushing of the necks, and possibly the use of a mandrel to "iron out" the necks following neck turning. (No lube, graphite, moly, etc was used.) This is important, as it is believed that any damage to the bullet base or jacket during seating will have an effect on short and long range accuracy and precision due to effects on such things as bore seal, bullet release at the barrel crown, bullet concentricity, and BC.

1-how were the necks brushed? Bronze or nylon? Was intent to "remove" all visible traces of carbon or just remove loose material to allow carbon to stay in neck?
2-no "lubrication" for neck turning but was there lubrication for bullet seating? I am assuming no? Did I miss this statement?
Like others I would like to see cause and effect on groups. Great dissertation and thought provoking!

Geez, another thread that may cost $$$.

 

[Mike Matteson]

In turning my necks for thickness. I haven't used lube to do that. Maybe I am missing something? On the 280AI cases I cut in 2 steps to achieve the thickness I am after.

 

[ButterBean]

In turning my necks for thickness. I haven't used lube to do that. Maybe I am missing something? On the 280AI cases I cut in 2 steps to achieve the thickness I am after.

I lube the inside of the neck when turning, it feels a lot smoother that way to me

 

[Mike Matteson]

I lube the inside of the neck when turning, it feels a lot smoother that way to me

I do that also. The way I read it I was thinking on the outside of the neck. I can see that I've been think about it, didn't get me to far.
Thanks!

 

[Mike Matteson]

I just order out Lee crimping dies across the board in .220 swift, 22/250, 6mm, 25/06, 6.5, 7mm, 308 NM, 338WM. I couldn't get a clear answer from Lee on the crimping die. "Here we go again". I am thinking and partly understand that the die holds the bullet inline while crimping the neck only. Not touching the shoulder or another area. Which in part that's what I was told. What wasn't clear was there possible anyway the a part of the die would touch the case somewhere else. Being the die isn't built for my case configuration.
The reason for this question is. Have a 6mm/280AI rifle built, and having 25/280AI being built. I am hoping that the 6mm, and the .257 crimping die will work. No diagrams or configuration drawing or detail, to show the inside of the die, and how it's built. If not I got a friend that can adapted it or build me one if needed.
Can anybody supply or send me a detail on inside of crimping die, so I can better understand what I am up against.

 

[Tiny Tim]

Your shell holder pushed the sleeve with the crimping collet up into a taper that makes the crimp. Same principle as a collet on a router.

 

[ButterBean]

I just order out Lee crimping dies across the board in .220 swift, 22/250, 6mm, 25/06, 6.5, 7mm, 308 NM, 338WM. I couldn't get a clear answer from Lee on the crimping die. "Here we go again". I am thinking and partly understand that the die holds the bullet inline while crimping the neck only. Not touching the shoulder or another area. Which in part that's what I was told. What wasn't clear was there possible anyway the a part of the die would touch the case somewhere else. Being the die isn't built for my case configuration.
The reason for this question is. Have a 6mm/280AI rifle built, and having 25/280AI being built. I am hoping that the 6mm, and the .257 crimping die will work. No diagrams or configuration drawing or detail, to show the inside of the die, and how it's built. If not I got a friend that can adapted it or build me one if needed.
Can anybody supply or send me a detail on inside of crimping die, so I can better understand what I am up against.

LEE FCD

 

[DoneNOut]

View attachment 447730

LEE FCD

Redding taper! Lol

 

[Mike Matteson]

Thankyou.

 

[ButterBean]

View attachment 447762
Redding taper! Lol

Nice, I like it

 

[DoneNOut]

Nice, I like it

I guess one wouldn't chamfer much using a FCD, right?