Neck size or full length resizing for accuracy?

mack59 · February 17, 2005, 01:13 PM

I've always read and believed that neck sizing was the most effective way to achieve accurate ammo when reloading ammunition for the same bolt gun. However I have read on a number of forums and newsgroups now that full length resizing produces more accurate ammunition - I could see this if one had an out or round chamber - but why would full resized or non-resized new brass lead to tighter groups and more accurate ammo as some claim.

Also, unrelated, I have a Stoney Point OAL gauge - that I used on my Savage in 308 Win - I get different readings when I use it - when I use a firm push and the bullet sticks a little on the rifling I get one reading and when I use a soft push so I can just barely feel the bullet stick, I get another. The the firm and soft reading are consistent to themselves but the problem is that between the two there is a .1 of an inch difference. That seems like alot. Originally I set my bullet seating die depth using a smoked bullet, which as it turned out is consistent with the firm push measurement. I'm using Sierra 175 grn hpbt match bullets.

Ackley Improved User · February 17, 2005, 01:37 PM

Neck-sizing-only makes very good sense for increasing accuracy. It ensures that the bullet is centered when it engages the lands. Neck-sizing-only plus turning your necks will center the bullet even a bit more, but neck turning is negligible in hunting rifle accuracy, and not recommended unless your into benchrest rifle-type accuracy - the latter guns have have tight necks and require neck turning.

For hunting, however, neck-sizing-only is risky, because you may get a "sticky" case and have trouble ejecting and, thus, getting-in that critical second shot. I don't recommend neck-sizing-only for hunting, unless it's for varmints, wherein a miss is no big deal.

Rtlesnake · February 17, 2005, 05:15 PM

I agree neck sizing only helps accuracy. It made a big difference in my 6.5 Swede.
But then the problem started. I got another Swede and had to full length size and fire form them to that particular gun. I learned that the chambers in the two guns are different enough that they each required their own ammo. If I goofed and didnt label the reloads for which gun it was for, they would NOT chamber in a different gun.
Same with the 8mm. I have about 5 of them and the record keeping of which gun the reloads are for was just to difficult so I full length size all of them just so they fit all the guns.
The Swedes still get their own ammo. I can handle keeping the ammo for two different guns seperate but for 7 different guns....nope...too difficult!

CaseyC · February 19, 2005, 02:57 AM

Or you can try the best of both worlds. Partial Full Length Resizing (PFLR). PFLR "bumps" the shoulder back slightly and neck sizes, without sizing the body--this will, ALMOST, always ensure the cartridges will chamber in your individual rifle and retain the benefits of neck sizing. I shoot a number of 270W's, which operate at "magnum" velocities (SAMMI max pressure 65K psi). When shooting "warmish" loads, several of my 270's shoot more accurately with PFLR than with FL OR neck sizing. I have a couple hypothesises as to why, but really it's only speculation and may be specific to those individual rifles.

I tend to get the forum equivalent of a "blank stare" when I write about PFLR

. The Nosler manuals have a pretty good explaination how to set up your dies for PFLR.
Casey

Semper Paratus · February 19, 2005, 04:03 PM

Probably the biggest advantage of neck sizing is brass life. The cycle of resize back to spec fire trim and repaeat. Work hardens the brass and causes brass flow. The big contributor is the brass flow is the body just above the head. Depending on the rifle and the head space you might only get a couple of reloads prior to case head seperation. Man that can be real troublesome to say the least. A friend of mine has an Ishopore Enfield in 308, excuse me 7.62 NATO. When full lenths sizing the case is good for two reloads and then you see the warning signs on upcoming case head seperation. When necksized the limiting factor becomes the primer pocket holding the primer or case neck cracks. Of course neck sized for the Enfield don't work at all in the Rem 788 in .308

February 17, 2005, 01:13 PM	#1
mack59 Senior Member Join Date: July 14, 2004 Posts: 447	Neck size or full length resizing for accuracy? I've always read and believed that neck sizing was the most effective way to achieve accurate ammo when reloading ammunition for the same bolt gun. However I have read on a number of forums and newsgroups now that full length resizing produces more accurate ammunition - I could see this if one had an out or round chamber - but why would full resized or non-resized new brass lead to tighter groups and more accurate ammo as some claim. Also, unrelated, I have a Stoney Point OAL gauge - that I used on my Savage in 308 Win - I get different readings when I use it - when I use a firm push and the bullet sticks a little on the rifling I get one reading and when I use a soft push so I can just barely feel the bullet stick, I get another. The the firm and soft reading are consistent to themselves but the problem is that between the two there is a .1 of an inch difference. That seems like alot. Originally I set my bullet seating die depth using a smoked bullet, which as it turned out is consistent with the firm push measurement. I'm using Sierra 175 grn hpbt match bullets.

February 17, 2005, 01:37 PM	#2
Ackley Improved User Member Join Date: January 31, 2005 Posts: 56	Neck sizing only makes good sense! Neck-sizing-only makes very good sense for increasing accuracy. It ensures that the bullet is centered when it engages the lands. Neck-sizing-only plus turning your necks will center the bullet even a bit more, but neck turning is negligible in hunting rifle accuracy, and not recommended unless your into benchrest rifle-type accuracy - the latter guns have have tight necks and require neck turning. For hunting, however, neck-sizing-only is risky, because you may get a "sticky" case and have trouble ejecting and, thus, getting-in that critical second shot. I don't recommend neck-sizing-only for hunting, unless it's for varmints, wherein a miss is no big deal.

February 19, 2005, 04:03 PM	#5
Semper Paratus Senior Member Join Date: May 21, 2004 Location: Tidewater, VA Posts: 155	Probably the biggest advantage of neck sizing is brass life. The cycle of resize back to spec fire trim and repaeat. Work hardens the brass and causes brass flow. The big contributor is the brass flow is the body just above the head. Depending on the rifle and the head space you might only get a couple of reloads prior to case head seperation. Man that can be real troublesome to say the least. A friend of mine has an Ishopore Enfield in 308, excuse me 7.62 NATO. When full lenths sizing the case is good for two reloads and then you see the warning signs on upcoming case head seperation. When necksized the limiting factor becomes the primer pocket holding the primer or case neck cracks. Of course neck sized for the Enfield don't work at all in the Rem 788 in .308 __________________ Semper Paratus--Always Prepared

February 17, 2005, 05:15 PM	#3
Rtlesnake Member Join Date: January 31, 2005 Posts: 26	I agree neck sizing only helps accuracy. It made a big difference in my 6.5 Swede. But then the problem started. I got another Swede and had to full length size and fire form them to that particular gun. I learned that the chambers in the two guns are different enough that they each required their own ammo. If I goofed and didnt label the reloads for which gun it was for, they would NOT chamber in a different gun. Same with the 8mm. I have about 5 of them and the record keeping of which gun the reloads are for was just to difficult so I full length size all of them just so they fit all the guns. The Swedes still get their own ammo. I can handle keeping the ammo for two different guns seperate but for 7 different guns....nope...too difficult!

February 19, 2005, 02:57 AM	#4
CaseyC Member Join Date: November 29, 2004 Posts: 19	Or you can try the best of both worlds. Partial Full Length Resizing (PFLR). PFLR "bumps" the shoulder back slightly and neck sizes, without sizing the body--this will, ALMOST, always ensure the cartridges will chamber in your individual rifle and retain the benefits of neck sizing. I shoot a number of 270W's, which operate at "magnum" velocities (SAMMI max pressure 65K psi). When shooting "warmish" loads, several of my 270's shoot more accurately with PFLR than with FL OR neck sizing. I have a couple hypothesises as to why, but really it's only speculation and may be specific to those individual rifles. I tend to get the forum equivalent of a "blank stare" when I write about PFLR . The Nosler manuals have a pretty good explaination how to set up your dies for PFLR. Casey