Anyone have a good kneck turning process?

PaulS

I am not sure what you mean when you say "check headspace and record it."
Headspace is a chamber dimension that extends from the base of the bolt to the median line of the shoulder. (for all rimless and belted cases except for the H&H cases which are the only belted cases that are supposed to headspace on the belt)
In any event that dimension (headspace) NEVER changes unless the chamber is modified.

woods · Member Joined: Oct 15, 2005 Posts: 89

Hey Paul

I don't want to speak for jbird but what he means is that he is going to take the Hornady Headspace Gauge www.midwayusa.com/epro...mid=479704 and take a measurement with it which will give a relative caliper dial measurement from the case head to the point on the shoulder at which the gauge collet hits. It is true that this is not headspace by definition, which in my understanding is the distance from the case head to the point on the case that stops forward movement of the case in the chamber. For a rimmed case that would be the thickness of the rim, for any belted case that would be from the case head to the front of the belt until the case has expanded so that contact at the shoulder stops forward movement and with a semi-rebated non-belted case would be from the case head to the shoulder.

Essentially what would be measured is the distance to the datum point and the purpose would be to keep track of the progressive decrease in the amount of gap between the case shoulder and the chamber shoulder until you have contact. This contact would occur by chambering the case and would create a crush fit on the case between the case-head/bolt-face and the case-shoulder/chamber-shoulder. By doing this you would be able to monitor your cases and resize to the exact same dimensions every time.

PaulS

Wouldn't it be easier to do like I do and just neck size the cases? I haven't used a FL die in years and I never have any problems chambering rounds. I also don't have any problems with accuracy - all my rifles shoot 1/2 to 3/4 inch groups (five shot). My aggregate groups for the day rarely go over one inch.

chambered221

PaulS wrote:

I haven't used a FL die in years and I never have any problems chambering rounds.

Don't you ever get to a point that FL sizing is a must ?????????????

I've tried NK sizing and partial NK sizing in my varmit rig (6MM Rem. ) and can not close the bolt after the third reload !!!!!!!!!!!!!

woods · Member Joined: Oct 15, 2005 Posts: 89

Supposedly you are wearing out the lugs and your chamber by neck sizing only but it would take years to actually do that. Some calibers and rifles never develop as severe a crush fit as other calibers and rifles.

I am with 221 though, most of my rifles develop a severe enough crush fit to cause problems I don't want to deal with, others have the camming action of the lugs to make even several times fired neck sized only cases chamber easy enough. Even on those I push the shoulder back .001" or so.

PaulS

My pat answer to the need to "set the shoulder back" is that the loads are too hot for your gun. In order for the brass to grow beyond the actual chamber size the chamber has to be expanding beyond the elasticity of the brass and then causing a crush fit as the chamber relaxes. I bet if you reduced your load you could go longer between the need to FL resize. My loads are at a point where accuracy is as good as I can get it - that is usually at 93% to 97% of max load. The pressures are low enough that the chamber never expands beyond the elsticity of the brass. I am currently loading brass that has been fired over twenty times and only trimmed once. I don't get max velocities but I get .5 to .7 MOA groups.
I know that you will argue that the load is not too hot for your guns but the brass is telling you a different story. Just my opinion from my experience. I am not telling you that you shouldn't load what you do - just the difference between what I do and what I hear others are doing.

chambered221

PaulS, Thanks for the info !!! sorry it took so long to get back. (unplanned vacation )

I can agree in the fact that hotter loads can be a issue as you've stated.
I have 3 loads for the 6MM and the hottest of them can only be shot three times befor a FL sizing is needed.
The target load is about 2 grains under max and I can go about 5 reloads.

woods · Member Joined: Oct 15, 2005 Posts: 89

Update on do-nuts:

I develop do-nuts on a 280AI Hart rebarreled rifle with a .313" neck. The bullet will only go in so far until it hits the neck/shoulder junction where the do-nut develops

The reason is that I turn the necks to get .004" clearance around the neck in the chamber. For anyone interested in the math it would be .313"-.284"=.029"-.0125"-.0125"=.004"

Now when I fire the rifle the neck expands to the chamber size and that will make the inside diameter of the neck .004"

I have the Forster hand turner and I was wondering if their reamers would fit so I sent off for one in .284"

It does!

So when I insert the reamer in lieu of the mandrel I can ream the inside of the neck and touch up the outside of the neck at the same time

And it gets rid of the do-nut

The inside of the neck is a little rough

but a little case prep with some steel wool

and it comes out shiny and smooth (well at least shinier and smoother)

and the case neck is a very consistant .012"

How's that for an anti-donut? Very Happy

I left 5 cases with the do-nut still there and plan to do a side-by-side comparison of groups to see if it helped or not. Will advise.