Confused about case necks

[WANTASHOOT]

I am working with a 6.5-06 Ackley Variant. I purchased the rifle with intentions to learn about Wildcat cartridges first hand. So here I go trying to learn.

The parent case I am using,they came with the gun) Is the 270Win. When I run the case thru the neck sizing die it shrinks the inside neck diameter to .256 which is too tight for a .264 bullet. I was thinking I need an expanding button that will bring it back to about .261 or so. The die is a Newlon Precision so I called them to get an Expander Button. Thier advice was to neck turn prior to neck sizing because an expander button will not expand the neck uniformly because the case is not supported by the die when it expands.,makes sense)

I started by making a chamber cast of my rifle. The chamber neck diameter of the CerroSafe is .2917 then subtract the expansion of CerroSafe .0025 the final dimension is .2892.

Bullet dia .264 + case neck thickness .014*2 = .292. This is too tight obviously.

Time to turn necks I cut the neck to .012 and then neck sized this shrinks the inside neck dia to .261 which is just about right. .264+.024=.288 .2892-.288=0012/2=.0006 Neck clearance. Pretty tight.

If I neck turn to .0115 neck thickness then size the case the inside neck dia becomes .264 and the bullet will not be retained.

Any advice.

 

[benjamin199]

In my opinion, you would be better with at least .003 total clearance between your loaded round and your chamber, to do this you will have to turn a little more off. To get the neck tension that shoots best I would recommend switching dies to one of the brands that uses the changeable neck bushings. I have had very good luck with the Redding type S match grade dies.
Good luck.
Ben

 

[rayjay]

Doesn't the Newlon die use bushings?

 

[Rtheurer]

Wow! thats alot of math for the mathmatically challanged such as myself.

This is how I do it. Im certainly not an expert on this topic but Ill explain how i do it and you can decide if it will work for you.

I would take the parent case,270) run it through the die. Take a bullet, the actual bullet you intend to use, they all very in Diameter a little) seat it in the case. Take my Mic and see what the overall Neck diameter with the actual bullet I intend to use is .292
, Im guessing the newlon die is the non bushing style one)
Lets say its what you computed, and some times it does not work out that way)
I know my neck demension, as I own all my own reamers, since you dont have that you are stuck with the chamber casting. Do nt you need to add .0025 for the srinkage of the casting? If Im correct,?) that would be a .2942 NK in which would give you .002 NK clearance, perfect) No turning required. Unless you wanted to clean up the necks another .001 which would be fine too.
OK lets say you do have a .289 neck in the chamber. You need only turn off .001 to .003 of the actual chamber size. I prefer .002. So .002 minus the .289 is .287 loaded round. .287 Minus your current .292 is .005 worth of turning of the neck in this istance. That is if your casting # is correct.

OK lets go back to your sizing problem. That is a real tight neck on your sizer. most and I say this in very general terms like between .001 to .003 neck tension. From the above sample of .287 loaded round you should have a die that gives you .286 to .284 after you have turned your necks to the correct size for clerance in the chamber.
Wow I think I have confused myself. Can anyone else explain this better?? My attempt to do so is futile.

Bottom Line
.002 loaded round clearance.

And size the brass about .002 smaller than loaded round diameter.

Good god I appolagize for the above. : ) Clear as mud right?

RussT

 

[janderson0]

I have a problem understanding a few things in your post.

How are you measuring the ID of the neck. I do not have the tools to this. What are you using.

You have taken the clearance than divided it by 2 to get .0006 when in fact your numbers show a .0012 clearance.

How can a .012 thick neck when run through the die yeild an ID of .261, then remove .0005 more, total of .001, run through die again and yeild .003 larger ID?,.002 more than it should be)

I've never used CerroSafe, but my understanding is it at first shrinks a bit,easy to remove) then in about one hour expands to exact size, then takes about 200 hours to expand to the .0025 over point. When did you measure?
Jim

 

[Cheechako]

Is it just me or are you guys making this waaaay more complicated than it needs to be.

If we're talking about a 6.5-06 type wildcat, in a non-benchrest rifle, why not simply run the 270 case into a full-length sizing die with a 6.5 expander button, load them and go shoot?? If you later decide that you want to turn the necks,why you would I can't imagine) simply turn them an amount sufficient to clean up 75% of the outside, get the correct size bushing for your sizer and go back to loading and shooting.

The Internet is a wonderful thing but it's taking simple things like shooting and turning them into rocket science. Turning case necks on an average rifle will not result in any meaningful difference in accuracy and may actually do more harm than good. Bushing sizing dies and straight-line bullet seaters are a waste of money with most cartridges. Your money would be better spent buying components and learning how to shoot.

JMHO

Ray

 

[janderson0]

Ray,

I'm just trying to make sense of the measurements, but it looks to me like he does have a tight neck chamber, and will need to turn. The question becomes how much.

Jim

 

[Cheechako]

Jim

It may well be a tight chamber,I'm not positive that subtracting .0025' for cerrosafe contraction is correct) but even if it is there is a far simpler way to skin this wildcat.

1. Load a dummy round with the bullet you will be using. Measure the neck diameter. Try to chamber it.

2. If that cartridge cannot be chambered, turn the neck on a case a little at a time until a cartridge will just barely enter the chamber. Measure that neck diameter and that will be your maximum neck size.

3. Turn another neck to that size minus .002 or .004,whatever clearance you're after), load it and fire it.

4. Measure the neck diameter of the fired case.

You now have all the dimensions that you will ever need, even if you decide to change brass. Put those samples in the box with your dies.

In most factory rifles, and quite a few customs, you'll never go past step 1.

Ray

 

[WANTASHOOT]

Janderon0
I have been using inside calipers to measure. They are accurate to .001.
You are correct on the clearance number
As for your 3rd question. If the OD is smaller when you run it thru the die the ID will also be smaller. I dont know the math but it works.
Cheechako
I wish it was that simple. If I just load it and go the shells wont fit in the chamber.

I do thank every one for the imput so far.

 

[WANTASHOOT]

Thanks fellas. That is exactly the track I am on. I was hoping to hear somthing like the last two posts. Since that is pretty much where I was headed.
My firts response was a little bit late. Darn job it keeps getting in the way of my hobby.

I will be getting a bushing die you can count on that.

 

[Rtheurer]

Ray

Thank you. That is what I was trying to say but failed horrably. Another cup of coffe is in order. I have two tight NK guns and now have come to the conclusion its a pain in the ass and most likely go back to the No turn Min. neck way of doing things. For my game its just too much to keep up with doing 200 peices of brass every year.

RT

 

[Winchester69]

I've just skimmed over this thing, but the tight chamber determines the wall thickness of the brass. If you can't live with the thin neck walls, then the chamber must be re-cut. I'd try living with thin neck walls. For BR, the walls aren't that thin.

If your Newlon die is correct for the wall thickness that is in turn correct for your chamber, another die will just have to do the same job.