How much of the neck to size?

[bailey1474]

I'm going to load up some once fired stuff in my 6-250 and was wondering how much of the neck I should size w/my Redding bushing neck die. Should I size the entire neck, 1/2 of the neck or something else? I'll have about .0015 neck tension if that matters.

Thanks,
B.J.

 

[winmagman]

Bill
I'm working on setting up a 6.5 wssm that I will be using Redding FL bushing dies for. I will be setting up to size the entire neck and bump the shoulder back .001-.002. Not sure that's the "right" way to do things but I gotta start somewhere.

Chris

 

[bailey1474]

My die is not a FL die though. It's just a neck die. I've got the body die for bumping the shoulder. If it was a FL I'd probably do just what you are doing.

 

[Bart B]

I'd size all of the neck and bump the shoulder back about .002-inch using a full-length sizing die. This is how the folks who've produced the smallest groups of 10 or more shots at long range size rimless cases. Sizing all of the neck usually results in the case neck being straighter and better aligned with the case body. And that means bullets seat straighter and have less runout.

 

[uncleB]

Bill,
start by backing off 1/4 turn so that the bushing is not on a bind then check runout on a concentricity guage if you have one. this should size about 3/4 of the neck ,that is just fine because with that die you cant size 100% of the neck. .0015 neck tension is good just make sure the neck wall thickness is the same on all your cases so the tension is consistant. and as always if you do exactly the opposite as BartB suggests your going in the right direction.
UB
p.s. have you got a straight 6-250 or is it an improved ??

 

[Bart B]

UncleB, you are a star. A distant star, but still a star.

 

[jb1000br]

Bart -- don't worry -- UB doesnt like me either /ubbthreads/images/graemlins/smirk.gif

Bill -- here is what i do with redding's s-dies...use it or don't /ubbthreads/images/graemlins/grin.gif

start with the bushing floating (stem backed off 1/4-1/2 turn)...run a case in the whole way and start to pull the ram back out...while keeping down pressure tighten the stem.

keeping down pressure on the ram while tightening the stem should center the bushing as it is tightened.

works for me...YMMV, and do confirm that is works with your conc. gage.

JB

 

[Waltech Jim]

Bill,

When recoil is not a concern I have been resizing only enough of the neck to hold the bullet in place, which is not very much sometimes. Usually this is less than half the length.

Jim

 

[bailey1474]

Thanks for all the suggestions guys.

UncleB,

It is a straight 6-250 and all my cases have had the high side shaved off the neck. I played w/the thing a little last night. When I run my fired case over the Sinclair gauge, my neck runout is < than .001". Way less, the needle barely moves. After running them through the die, I get .001 to .003 neck runout. What's wrong??

I tried moving plunger and giving the bushing more, and less room to float around, but nothing seemed to improve the situation. I loaded 20 rounds and almost all of them had about .002-.003 bullet runout. Is this acceptable or should I strive for better?

Maybe I'll try JB's idea tonight and see what I get.

Thanks guys!!!

 

[arthurj]

That certainly shows what a straight chambering job Kirby did!
I read one time to try running the case neck halfway into the bushing, then backing it out and rotating the case 180 degrees, then run it comletely into the die. Also you could try flipping the bushing over, unless you have already tried that.

 

[Fiftydriver]

BJ,

THis is one reason I do not care much for the S-type dies if that is what you are using, no case body control while the neck is sized.

Make sure everything is totally clean in the bushing chamber. If there are any brass chips under the bushing they will throw off your Run outs.

Also, a little tip, do not lock the die down in the press. Usually the threads are off slightly on the die and press so if they are and you lock the die down you get this showing up in your case necks. Let the die float as you size cases and it tends to help center itself better then if its locked down.

Best way to fix things, A Redding Comp Bushing neck sizing die. Total case body control as the neck is sized, run outs generally are in the 0.0005" range when set up and cleaned properly.

Your run outs are not bad but not great. May be about as good as you will get with an S-type die. This is the problem with them, consistancy, many cases will be very good, here and there you will get 0.003" run out for no explained reason, just the nature of the beast when the case body is unsupported.

Wear in your press will also show up in your run outs using this type of die, as will out of concentric shell holders. All of these are corrected with a Redding Comp Bushing neck sizing die because the Die actually controls the case body, not the shellholder.

Hows she shooting by the way???

Kirby Allen(50)

 

[victor]

Bill,

This is what I do:

1. I lightly neck turn to only shave off high spots on my neck wall.

2. Fire form case to get dimensions to fit my chamber.

3. Neck size 3/4 of the neck and leave the remaining 1/4 of the neck to center that portion of the neck in the chamber.

At this point I need to point out that you can oder various bushings to compress your neck a certain amount. You have to measure your chambers neck diameter and then get a bushing that will reduce your cases neck diameter by .003. (Read Reddings recommendation on this, I'm going from memory) What you want to do is deform your case neck as little as possible. The more you compress it the more chance there is that it will go out of round from the perfect fire formed condition. Also, the less bending the longer you cases last.

Now, why do your necks go out of round from the fire formed perfect condition. Because the neck case material is not 100% consistent. One side may be harder then the other and the softer side will bend/deform easier than the hard side. result, you go out of round by the amount that you are compressing the brass. So the less compression/deformation, the less out of round variance you will have.

Since the "S" bushing floats, it does nothing for concentricity. If the brass material was 100% uniform, it would follow that you would get 100% concentricity on the compressed portion of the neck. But sorry to say nothing is perfect, chaos rules.

Would a button expander help. No! It sits near the bottom of the die on a flexible shaft.

Would a full length resizer die do more for concentricity?
In theory yes. But remember, Chaos Rules! The runout tolerances in your die between the case body and neck are, who knows what.

If you want to tame chaos, you need to have Kirby make you a die with the same reamer that he used to make your chamber.

Good day,
Victor

 

[bailey1474]

Kirby,

It's only money right? I might have to see if I can find one of those dies. I do have a 1/2 voucher for anything from Redding.

[ QUOTE ]
Hows she shooting by the way???

[/ QUOTE ]

We'll get into that after my shoot this weekend. Hopefully I'll have a trophy of some kind to put in w/my review of this little gem. For now, we'll just just say that I've got some sub 2" 400 yd targets that I know I can improve on!!

 

[jb1000br]

[ QUOTE ]
If you want to tame chaos, you need to have Kirby make you a die with the same reamer that he used to make your chamber.

[/ QUOTE ]

That wont do you any good...