Re-Turning Necks

A

abintx

Guest
Just curious. Is it OK to re-turn 6PPC necks after the brass has been fired a few times or a number of times ???

It will be going back into the same chamber that it was fire formed in. I use Lapua brass exclusively. Art :)
 
NO...ABSOLUTELY NOT...send all that brass to my used brass disposal center for proper disposal...address will be sent in a PM...:D:D:D:D:D:D
 
I really doub't that re-turning necks on fired cases is good. That said,
I know people that do it and shoot good. There is almost always some
donut in the case, and the pilot will run tighter there even after re-expanding
But even with out the donut, The shoulder neck junction springs back a
little tighter. This allows the mid section to remain larger in the I.D.
So the mandrill does not fit the same. Using a magic marker, color the
I.D. and then return it. Where the mandrill is tightest can be seen, and it
will rarely be even. On the other hand, Some guns can be found to shoot
better with a bit more clearance. I have been rethinking this neck thing
and wonder if the perfect necks I try for is really a plus or is there a
window in neck clearance. When the trigger is pulled, the base of the bullet
must move first, thus it expands. Cases turned with total clearance of
.0003 tenths can also be found thinner at a midpoint after firing.
Go Figure
 
Some shooters as a matter of process turn the necks to about 0.0015" total clearance then after a couple of fire formings they take the additional 0.0005" off. With a hand held turner this is probably the best, but not totally necessary, method.

The most precision method to turn necks is on an engine lathe if you happen to have one or have access to one.
 
I See No Problems

I just re-turned about 150 cases, the ones I used at The Nationals. They have about 10 firings each.

The reason I re-turned them was I am trying a bullet that has about a .0004 gas ring, the bullet I have been using does not have any. This gave me a little to play with.

Keep in mind, though, I do not do necks with a hand turner. I single point them in a lathe. And, since I blow my cases out before I turn the necks the first time, I have no do-nut to deal with............jackie
 
Jackie

I fireform my cases with a stiff load of 4198 dupont. Then ream them
for a uniform finish and fit on my mandril. they are then turned on
the outside. The donut comes back. This is shoulder moving into
the neck. If this didn't happen we would never have to trim brass.
This is amplified with smaller neck diameters, because the shoulder is
thicker than the neck. With a .269 neck as I recall that you use, it
would be almost non existant.
They are fireformed in a dedicated barrel with 22 bullets
 
Last edited:
Jackie,

How are you loading your cases for the blow out before turning?

Octopus
 
Bob Kingsbury said:
I fireform my cases with a stiff load of 4198 dupont. Then ream them
for a uniform finish and fit on my mandril. they are then turned on
the outside. The donut comes back. This is shoulder moving into
the neck. If this didn't happen we would never have to trim brass.
This is amplified with smaller neck diameters, because the shoulder is
thicker than the neck. With a .269 neck as I recall that you use, it
would be almost non existant.
They are fireformed in a dedicated barrel with 22 bullets
Click to expand...


I DON'T ever have to trim necks. Not in 50 firings w/PPC.

And never form donuts.

al
 
I shoot HOT....... I shoot everything hot from my PPC's to .22 and 6BR's, 6X47L and 30X47L, .308 and variants on this case, and the WSM cases..... I don't do this for velocity but for consistency.....velocity is a sidebar issue.

and I use fitted dies....

And I make my brass very carefully, avoiding donuts.

And with proper die fit and setup I can full-length resize any or all all of these cases listed above as many times as I want and they will not grow.

Donuts and case growth are the direct result of shoving the case too far into the die, over-sizing.

The only case I'm fighting a little is the WSM case when fired in a standard tenon action.... I'm seeing longitudinal stretching which results in waviness in the casebody just below the shoulder/body junction. I've needed to shim to the 1/2thou for this deal and I've not fired a case more than 12 times. I MAY have to abandon the idea of long case life in WSM cases using standard diameter actions. This is speculative.

But definitely all the case sizes listed OTHER THAN WSM can be resized many times without growth, in a standard tenon action.

Provided proper fireform and fit.

I also have my reamers made with sharp corners..... I don't know the number, Gene Beggs might, but I spec them "minimum radius" on the corners. I'm not sure how important this is but I suspect it's helpful.

On the flipside, I'm also fairly certain that no one on God's Earth has found a way to successfully FL size Weatherby shoulders without growth.

al
 
Octopus

I really hate to say how I (and many others), do this, because it always brings up a issue of safety.

I just load a 220 Russian with 133 and a cheap 22 bullet and fire it in my .269 neck chamber. What comes out is a fully formed Factory 6PPC Case, ready for neck turning.

But, if you do this, make sure you are using a close backstop, (25 yards), to shoot into. Those 22 bullets are rattling around in that barrel, and there is always the concern that they will overshoot a burm at 100 yards........jackie
 
I also fireform 6ppc with a 22 bullet. I use a stiff load of IMR 4198 and
shoot into a dirt pile about 10 feet away. This is done with an old barrel
which has a .265 neck. Cases are then reamed in a jig which guides the
reamer. There is a slight choke area inside at the base of the neck, which
I believe comes from the added support of the shoulder allowing it to spring
back slightly. The reamer is actually a throating reamer and my turning mandrill is matched to that. Any roughness or out of round is pretty well
eliminated . All cases have a very uniform , but snug fit on the mandrill.
Each case is turned first with an initial cut and then completed with
a finish cut.Across 50 cases wall thickness varies about 1/2 tenth.
After firing in my good barrel 3-4 times, I find a .243 chucking reamer
which measures .2435 will just enter the neck, but will stop in the shoulder
junction. Its pretty hard to find otherwise. My assumption is that it is a
donut reappearing. I probably never have to trim, but do for uniform length.
 
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