Neck sizing question

odsixer · December 3, 2007, 12:28 AM

Neck sizing is supposed to be accurate because the case is fireformed to the chamber of a given rifle...I think.

The only problem I see is after a few firings you have to fl size or your cases will begin requiring a hard close with the bolt. From an accuracy perspective won't fl sizing your cases then change the inside volume and therefore the pressure affecting accuracy(poi)?

Just wondering, I'm sure the change in pressure would be minor but could it shift poi?

MADISON · December 3, 2007, 08:12 AM

Special NECK SIZING DIES
I E-Mailed RCBS on December 12, 2004 and received the following response on December 15, 2004.

From an old #8 Speer Reloading Manual. You and other equipment manufacturers sell special NECK SIZING dies. Does this still apply to your equipment?

Neck Sizing is the term applied to the process of sizing only the neck of a case, with a special die which doesn’t touch the shoulder or body of the case. Neck sizing does eliminate excessive working of the case shoulder and body but, also, may size the neck off-center and leave the body of the case too large to chamber. A better way to reduce excessive working of the case body and shoulder metal is to use a full length sizing die but, use it so it only sizes partially. To do this, the full length sizing die is backed out of the tool so that the shoulder is not touched by the die. This preserves the important head and shoulder dimension and still sizes the neck normally. The body of the case centers the neck in the die and is sized enough to make chambering fairly easy in a bolt action.
Back the die off at least 1/16th of an inch [About one complete turn.]
Many shooters adjust their dies so that only half of the neck is sized. This leaves enough tension to hold the bullet securely for target or varment shooting

The RCBS “Ask the Expert Forum’s response was:
Yes, the necksizers only size the neck of the cases. And yes, there can be run-out after necksizing as there is nothing to support the base of the case - it just sizes the neck. AS FOR PARTIAL SIZING -- Many of our customers choose to do this - but, it is trial and error and sometimes the chamber v.s. die fit does not allow the reloader to partial size - they will not chamber afterwards.

Martyn4802 · December 3, 2007, 09:22 AM

Full length sizing will not afftect accuracy enough to worry about. For benchrest shooting competetively, neck sizing is important, but not for hunting.
I now full length size all of my cases so they feed well during hunting situations where a rapid second and third shot are necessary.

Martyn

arkie2 · December 3, 2007, 10:12 AM

I neck size only for range ammo, not for the supposed increase in accuracy but because it's much less labor intensive without the need for lubing. When I hunt I buy factory ammo.

Alleykat · December 3, 2007, 10:18 AM

Depends on what you're hunting, whether you'll need that "extra bit" of accuracy or not. If you're shooting a giant mammal, like a deer, etc., where 7-yr-old girls with SKSs routine make kills, then, of course, you won't need the extra accuracy.

If you're trying to hit a small varmint @ 300 yds., then you just might appreciate the extra accuracy. As to the negative effect of f.l. resizing after a few neck-sizings, you'll only have the negative effect (as miniscule as that will probably be) on the first firing. From then-on, it's the advantage of neck sizing, all over again.

odsixer · December 4, 2007, 05:10 PM

Thanks for the replies, for accuracys sake i think i'm going to get a headspace guage and bump the shoulder 1-2 thou. back every time.

crowbeaner · December 4, 2007, 08:16 PM

Depending on the rifle's preference and caliber, I use the FL die backed out 1/4 turn. Run the first case all the way into the die and then tighten the lock ring to keep the die centered in the press, assuring perfect die alignment. Tighten the lock ring slightly before running the case back out. CB.

Ozzieman · December 4, 2007, 09:01 PM

For all bolt guns I neck size all cases once they have been fired. What I have found is that as long as the case’s are worked as little as possible they will be much more accurate over the life of the case.
In my shooting and reloading I have found the length of the case is much more important than the sizing.
My recommendation is to have a gunsmith or get a chamber length gauge and find the total length of the chamber and trim all your cases just under that by a couple of thousandths.
It’s the amount that the bullet jumps with out being supported by the lands of the barrel that can cause the most problems with the stability, spelled “accuracy” when it comes to the case. When you trim to the maximum by the book numbers, what you’re doing is making the length that will work for all guns manufactured.
Chamber length can vary by quite a bit and once you know the depth of your chamber for the gun then you can make all your cases perfect for your gun.
The tool needed to make this possible is a Wilson case trimmer. Believe me there is nothing better or easier to use.
http://www.sinclairintl.com/cgi-bin/...CWI&type=store

Alleykat · December 5, 2007, 01:39 PM

Quote:

Thanks for the replies, for accuracys sake i think i'm going to get a headspace guage and bump the shoulder 1-2 thou. back every time.

If you're going to be bumping the shoulders ever time you load, then, apparently, you haven't understood why one neck sizes to begin with. If you're bumping the shoulders every time, you're sure as hell not doing it "for accuracy's sake."

steelbuster · December 5, 2007, 07:14 PM

When I am trying to develop an accurate load for my rifles or single shot pistols I do the following puttsy process ( mostly 'cause I'm retired and have nothing better to do)
I always start with Federal factory ammo if available as I feel its the best brass. Using once fired brass, and the specific bullet chosen for the load, I insert the bullet in the case being sure to leave the COL (Cartridge Overall Length) long enough that the bullet is pushed back into the case as the round is carefully chambered. I do this several times to find the exact COL that puts the bullet against the rifling and record that dimension.
I then neck size the brass and assemble 7 rounds using a COL that is .030" less than the base COL recorded in the first step, and then keep reducing the gap until I get to .010" off the rifling leade. Usually, at some point between .030 and .010 I get the best accuracy.
Be cautious with this as the pressures will definitely be higher than a round loaded to the standard length. Not a lot perhaps, but something to be aware of if using Max loads. If you get the bullet right against the rifling the pressure can be quite a bit higher and I never do that.
This procedure can be tough to do if using bullets with a lead tip as measuring the length and setting up your press is made difficult by the soft tip, but as I said in the beginning, I'm retired.

Try using your press die to measure down on the shoulder of the bullet instead of the tip.
I use this for every barrel I have, from .223 to .45-70 and have found some real accuracy increases over standard length rounds.
Good luck.

odsixer · December 5, 2007, 07:42 PM

Alleykat, this is what I'm confused about. Accuracy from a reloading standpoint is the same as "repeatability" so if you neck size only great, but what happens after a few firings and your cases start getting tight, you have to partial or full length re-size. My thoughts are you've now changed your pressure and therefore poi?

Steelbuster thanks for the info, I will play with seating depth after finding an optimal charge weight... I thought the bullet seaters contact the ogive and not the tip???

arkie2 · December 5, 2007, 09:02 PM

Depends on what you're hunting, whether you'll need that "extra bit" of accuracy or not. If you're shooting a giant mammal, like a deer, etc., where 7-yr-old girls with SKSs routine make kills, then, of course, you won't need the extra accuracy.

You mean if I'm trying for a Moose or Elk as opposed to a marmoset at 1,000 yards? OK. Got it.

steelbuster · December 5, 2007, 10:12 PM

Quote:

Steelbuster thanks for the info, I will play with seating depth after finding an optimal charge weight... I thought the bullet seaters contact the ogive and not the tip???

Thats correct. I'm not sure what your referring to?
I was trying to explain a procedure, for measuring and seating a bullet to a specific depth... the depth in relation to the chamber length. Sorry if I wasn't clear.

Regarding your POI question..The pressure doesn't change in relation to full length sizing. The case expands back to the chamber dimension as it's fired anyway.

odsixer · December 6, 2007, 12:14 AM

Quote:

The pressure doesn't change in relation to full length sizing. The case expands back to the chamber dimension as it's fired anyway

Thanks, this is what I was wondering, I'm fairly new to reloading and there's enough info online to make your head swim. I guess it's best to keep it simple as possible.

Alleykat · December 6, 2007, 05:34 PM

Yep, the only purpose for f.l. resizing a case that's previously been neck-sized only is to bump the shoulder.

raktrak · December 6, 2007, 06:39 PM

I use a trim die to align the necks and bump the shoulder back, followed by a neck size die . It works great. I called RCBS and found out the trim die will align the neck and set the shoulder,but leaves the sizing for the neck die. It also gives a quik check to see just how long your cases are getting. I especially like the fact that it aligns the neck with the body. Somtimes I use an expander die to give perfectly round even grip on the bullet and then use the neck die.

tuck2 · December 6, 2007, 11:30 PM

I have ben trying out the Redding Competition Shellholder Set with a Redding full length 17 Fireball die. The five shell holders are + .002, .004, .006 , .008, and .010 of an inch longer than the standered shell holder. By starting with the + .010 holder and working down one can find which holder will allow the case to chamber with very little case set back. Sofar I have reloaded the 17cases five times with out any split cases or other problems. I have yet to try the No. 10 shell holder set with the 17 Rem, 221 Fireball, and 223 Rem cases but that will take a while.

December 3, 2007, 12:28 AM	#1
odsixer Senior Member Join Date: May 17, 2007 Location: great white north Posts: 316	Neck sizing question Neck sizing is supposed to be accurate because the case is fireformed to the chamber of a given rifle...I think. The only problem I see is after a few firings you have to fl size or your cases will begin requiring a hard close with the bolt. From an accuracy perspective won't fl sizing your cases then change the inside volume and therefore the pressure affecting accuracy(poi)? Just wondering, I'm sure the change in pressure would be minor but could it shift poi?

December 3, 2007, 08:12 AM	#2
MADISON Senior Member Join Date: January 1, 2000 Location: Roanoke, Virginia Posts: 2,678	Neck Sizing with Full Length dies Special NECK SIZING DIES I E-Mailed RCBS on December 12, 2004 and received the following response on December 15, 2004. From an old #8 Speer Reloading Manual. You and other equipment manufacturers sell special NECK SIZING dies. Does this still apply to your equipment? Neck Sizing is the term applied to the process of sizing only the neck of a case, with a special die which doesn’t touch the shoulder or body of the case. Neck sizing does eliminate excessive working of the case shoulder and body but, also, may size the neck off-center and leave the body of the case too large to chamber. A better way to reduce excessive working of the case body and shoulder metal is to use a full length sizing die but, use it so it only sizes partially. To do this, the full length sizing die is backed out of the tool so that the shoulder is not touched by the die. This preserves the important head and shoulder dimension and still sizes the neck normally. The body of the case centers the neck in the die and is sized enough to make chambering fairly easy in a bolt action. Back the die off at least 1/16th of an inch [About one complete turn.] Many shooters adjust their dies so that only half of the neck is sized. This leaves enough tension to hold the bullet securely for target or varment shooting The RCBS “Ask the Expert Forum’s response was: Yes, the necksizers only size the neck of the cases. And yes, there can be run-out after necksizing as there is nothing to support the base of the case - it just sizes the neck. AS FOR PARTIAL SIZING -- Many of our customers choose to do this - but, it is trial and error and sometimes the chamber v.s. die fit does not allow the reloader to partial size - they will not chamber afterwards.

December 3, 2007, 09:22 AM	#3
Martyn4802 Senior Member Join Date: June 12, 2007 Location: Grayling, Michigan Posts: 737	Full length sizing will not afftect accuracy enough to worry about. For benchrest shooting competetively, neck sizing is important, but not for hunting. I now full length size all of my cases so they feed well during hunting situations where a rapid second and third shot are necessary. Martyn __________________ US Army Retired NRA Benefactor Life Member JPFO

December 4, 2007, 08:16 PM	#7
crowbeaner Senior Member Join Date: June 4, 2007 Location: Upstate SC Posts: 1,943	Depending on the rifle's preference and caliber, I use the FL die backed out 1/4 turn. Run the first case all the way into the die and then tighten the lock ring to keep the die centered in the press, assuring perfect die alignment. Tighten the lock ring slightly before running the case back out. CB. __________________ If you want your children to follow in your footsteps, be careful where you walk. Beware the man that only owns one gun; he probably knows how to use it. I just hope my ship comes in before my dock rots.

December 5, 2007, 07:14 PM	#10
steelbuster Member Join Date: December 1, 2000 Location: Indiana Posts: 66	When I am trying to develop an accurate load for my rifles or single shot pistols I do the following puttsy process ( mostly 'cause I'm retired and have nothing better to do) I always start with Federal factory ammo if available as I feel its the best brass. Using once fired brass, and the specific bullet chosen for the load, I insert the bullet in the case being sure to leave the COL (Cartridge Overall Length) long enough that the bullet is pushed back into the case as the round is carefully chambered. I do this several times to find the exact COL that puts the bullet against the rifling and record that dimension. I then neck size the brass and assemble 7 rounds using a COL that is .030" less than the base COL recorded in the first step, and then keep reducing the gap until I get to .010" off the rifling leade. Usually, at some point between .030 and .010 I get the best accuracy. Be cautious with this as the pressures will definitely be higher than a round loaded to the standard length. Not a lot perhaps, but something to be aware of if using Max loads. If you get the bullet right against the rifling the pressure can be quite a bit higher and I never do that. This procedure can be tough to do if using bullets with a lead tip as measuring the length and setting up your press is made difficult by the soft tip, but as I said in the beginning, I'm retired. Try using your press die to measure down on the shoulder of the bullet instead of the tip. I use this for every barrel I have, from .223 to .45-70 and have found some real accuracy increases over standard length rounds. Good luck. __________________ Get your facts first, and then you can distort them as much as you please..

December 3, 2007, 10:12 AM	#4
arkie2 Senior Member Join Date: September 3, 2006 Posts: 475	I neck size only for range ammo, not for the supposed increase in accuracy but because it's much less labor intensive without the need for lubing. When I hunt I buy factory ammo.

December 3, 2007, 10:18 AM	#5
Alleykat Junior member Join Date: July 26, 2007 Posts: 3,668	Depends on what you're hunting, whether you'll need that "extra bit" of accuracy or not. If you're shooting a giant mammal, like a deer, etc., where 7-yr-old girls with SKSs routine make kills, then, of course, you won't need the extra accuracy. If you're trying to hit a small varmint @ 300 yds., then you just might appreciate the extra accuracy. As to the negative effect of f.l. resizing after a few neck-sizings, you'll only have the negative effect (as miniscule as that will probably be) on the first firing. From then-on, it's the advantage of neck sizing, all over again.

December 4, 2007, 05:10 PM	#6
odsixer Senior Member Join Date: May 17, 2007 Location: great white north Posts: 316	Thanks for the replies, for accuracys sake i think i'm going to get a headspace guage and bump the shoulder 1-2 thou. back every time.

December 4, 2007, 09:01 PM	#8
Ozzieman Senior Member Join Date: December 14, 2004 Location: Northern Indiana Posts: 6,117	I neck size all cases once they have been fired For all bolt guns I neck size all cases once they have been fired. What I have found is that as long as the case’s are worked as little as possible they will be much more accurate over the life of the case. In my shooting and reloading I have found the length of the case is much more important than the sizing. My recommendation is to have a gunsmith or get a chamber length gauge and find the total length of the chamber and trim all your cases just under that by a couple of thousandths. It’s the amount that the bullet jumps with out being supported by the lands of the barrel that can cause the most problems with the stability, spelled “accuracy” when it comes to the case. When you trim to the maximum by the book numbers, what you’re doing is making the length that will work for all guns manufactured. Chamber length can vary by quite a bit and once you know the depth of your chamber for the gun then you can make all your cases perfect for your gun. The tool needed to make this possible is a Wilson case trimmer. Believe me there is nothing better or easier to use. http://www.sinclairintl.com/cgi-bin/...CWI&type=store

December 5, 2007, 07:42 PM	#11
odsixer Senior Member Join Date: May 17, 2007 Location: great white north Posts: 316	Alleykat, this is what I'm confused about. Accuracy from a reloading standpoint is the same as "repeatability" so if you neck size only great, but what happens after a few firings and your cases start getting tight, you have to partial or full length re-size. My thoughts are you've now changed your pressure and therefore poi? Steelbuster thanks for the info, I will play with seating depth after finding an optimal charge weight... I thought the bullet seaters contact the ogive and not the tip???

December 5, 2007, 09:02 PM	#12
arkie2 Senior Member Join Date: September 3, 2006 Posts: 475	Depends on what you're hunting, whether you'll need that "extra bit" of accuracy or not. If you're shooting a giant mammal, like a deer, etc., where 7-yr-old girls with SKSs routine make kills, then, of course, you won't need the extra accuracy. You mean if I'm trying for a Moose or Elk as opposed to a marmoset at 1,000 yards? OK. Got it.

December 6, 2007, 05:34 PM	#15
Alleykat Junior member Join Date: July 26, 2007 Posts: 3,668	Yep, the only purpose for f.l. resizing a case that's previously been neck-sized only is to bump the shoulder.

December 6, 2007, 06:39 PM	#16
raktrak Senior Member Join Date: November 27, 2005 Posts: 138	shoulder bump back I use a trim die to align the necks and bump the shoulder back, followed by a neck size die . It works great. I called RCBS and found out the trim die will align the neck and set the shoulder,but leaves the sizing for the neck die. It also gives a quik check to see just how long your cases are getting. I especially like the fact that it aligns the neck with the body. Somtimes I use an expander die to give perfectly round even grip on the bullet and then use the neck die.

December 6, 2007, 11:30 PM	#17
tuck2 Senior Member Join Date: April 25, 2007 Posts: 208	I have ben trying out the Redding Competition Shellholder Set with a Redding full length 17 Fireball die. The five shell holders are + .002, .004, .006 , .008, and .010 of an inch longer than the standered shell holder. By starting with the + .010 holder and working down one can find which holder will allow the case to chamber with very little case set back. Sofar I have reloaded the 17cases five times with out any split cases or other problems. I have yet to try the No. 10 shell holder set with the 17 Rem, 221 Fireball, and 223 Rem cases but that will take a while.