chamber neck od

[bheadboy]

now for you guys with answers, I have a newly acquired Rem 700 heavy bbl 26 12 twist in 223.

all seems to be reasonable in the chamber measuring the fired cases. EXCEPT the neck,

my loaded rounds of seated Sierra 50bk measure .247. the fired case neck (after spring back) measures .257 -- lots of carbon blow back on the neck

this seems like a lot to me, ?? do you experience loss of accuracy with such a condition?

Bob

 

[mikecr]

I would expect high ES, and difficulty in managing consistent neck tension.
I'm guessing you turned your necks to 11.5thou thickness

 

[jonbearman]

If the neck of the case is sooted the charge is on the light side. I have basically the same rifle and with light loads with unturned brass it still soots them a bit.

 

[bheadboy]

I am shoot over max and no pressure signs, high ES and SD

Bob

 

[jonbearman]

What powder are you using and the exact bullet being a 50 grain blitzking for the high es and sd?

 

[bheadboy]

SIerra 50 bk with Tac 27.4 gr and no pressure sign, this not to be used in any other gun as it is over max.

I also use 26.5 8208 with similar results. again over max. do not use.

bob

 

[CatShooter]

I have a 300 Win Mag, 1,000 yard match rifle with a large neck and it is incredibly accurate - your large neck will not effect accuracy, but you will need to learn the dark art of annealing.

 

[/VH]

OK - In the spirit of humor and in correlation with another current thread on this forum "Head Space vs. Shoulder Bump" where critics get criticized.............. and to shine some light on how others may perceive some of the 'stuff' that gets typed on here................ and to show that some of us may actually be paying attention to some of this 'stuff':

bheadboy,

I 'spect your chamber neck od is likely much closer to your barrel's major outside diameter than .010"-.012" larger than your loaded case neck diameter, or...........I think you would've gotten much more blow back than just carbon.

CatShooter,

Sanantonio del gato con queso!!!.............Just when I think I've might of advanced enough to hang with you; I find out you have a 1,0000 yard match rifle. I bet it is incredibly accurate and I 'spect you are well versed in more dark arts than just that of annealing. Guess I'll have to get back on the neck sizing only wagon! What powder are you using?

I also won't be surprised to find out you baited me into this since you left that "1,0000" on your post all night and I'll probably, in short order, get an introduction to the dark art of critiquing your post.

 

[CatShooter]

CatShooter,

Sanantonio del gato con queso!!!.............Just when I think I've might of advanced enough to hang with you; I find out you have a 1,0000 yard match rifle. I bet it is incredibly accurate and I 'spect you are well versed in more dark arts than just that of annealing. Guess I'll have to get back on the neck sizing only wagon! What powder are you using?

I also won't be surprised to find out you baited me into this since you left that "1,0000" on your post all night and I'll probably, in short order, get an introduction to the dark art of critiquing your post.

Snow shoe typing "Paw" syndrome -

Cut I'll cut you some slack and shoot with you with my eyes closed

 

[/VH]

"Cut I'll cut you some slack and shoot with you with my eyes closed"

OK, I've got plenty more feral cats that need killed but I think we'll have to find you a shootin' spot 2 or 3 canyons over!

 

[JohnHenry]

In my experience the normal Remington chamber neck diameter is .255 for 223 Rem. Assuming .001 spring back, your chamber would obviously have an approx .258 nk dia. Certainly not beneficial for accuracy or case life in my opinion. If I remember correctly Remington reduced the 222/223 neck diameter from .255 to .250 in the 40XBR to benefit accuracy. May want to try some Lapua match brass. The Lapua neck walls are thicker and the loaded neck OD will be approx .250.

FYI: Bullets.com has Lapua 223 match brass on sale for $43.95 per 100.
http://www.bullets.com/products/223-Remington-Match-Unprimed-Brass-Cases-Box-of-100/BL11058

 

[artbosco]

Anytime you can match up the center line of the barrel with the center line of a chambered cartridge accuracy will be moving in the right direction especially with the correct load married to barrel vibration.

Center line match ups are best achieved with a minimum neck chamber or better still with a tight neck chamber.

 

[CatShooter]

Anytime you can match up the center line of the barrel with the center line of a chambered cartridge accuracy will be moving in the right direction especially with the correct load married to barrel vibration.

Center line match ups are best achieved with a minimum neck chamber or better still with a tight neck chamber.

???


The size of the neck on the reamer has nothing to do with "center line match ups"... the alignment is determined by the lathe set up, and the proper fit of the reamer pilot... the reamer has already been cutting, and is on what ever "line up" it is going to have, before the neck section enters the barrel.

 

[Tozguy]

Anytime you can match up the center line of the barrel with the center line of a chambered cartridge accuracy will be moving in the right direction especially with the correct load married to barrel vibration.

Center line match ups are best achieved with a minimum neck chamber or better still with a tight neck chamber.

I think you are referring to getting the bullet lined up with the bore. The smallest clearance of a round in the chamber is usually the bullet shank in the throat which would be in the order .0005'' on the diameter.
Clearance at the neck of under .003'' should only be used under special cicumstances. When using only neck resized cases, the clearance of the body of the case in the chamber would probably be much less than .003''. All that to say that with a properly chambered barrel and concentric ammo, seating the bullets out long and only resizing the neck SHOULD do the best job of getting your bullet aligned with the bore. A tight fitting neck is not what i would count on for that purpose.

 

[Tozguy]

One thing that might help seal the neck to the chamber better is partial neck sizing. That way a portion of the neck would be much closer to the chamber already before firing. Just sayin'