Full Length or Neck Only; What's Best Resizing for Accuracy?

[highdrum]

I FL size, bump shoulder back 0.001-0.0015. I have never straight neck sized anything in my life of reloading.

 

[Bart B]

Everyone knows that LC Match brass is crap for concentricity in the neck and body, and the headspace is .005" smaller/shorter than the 1980 Rem 700 BDL Varmint I shot it through.

New primed M118 cases stuffed with IMR4320 under Sierra 190 HPMK's tested 20 shots in 3 to 4 inches at 600 yards in 7.62 converted Garands. A little better in bolt action match rifles

 

[tribb]

Ok guys, after reading this thread, you may be scratching your head and wondering if all the trouble JE and I are talking about is worth it. I will assure you it is not necessary if you want to shoot game at 400yds or less. If you want to shoot far it absolutely is. Allow me to share a story with you. The other day a friend of mine missed a deer. He asked me to go with him to check his rifle. He shoots a shelf rifle with factory loads from Wal-Mart. I loaded everything in the SxS and we went to where we have a range set up on our place. I put my rifle in since deer season was open. We sighted in his rifle without incident. He said "lets see you shoot that fancy rifle with those reloads you shoot". I said "ok, put up a clean target. He did, and I told him to get in the SxS. Started driving back toward camp. Went across the field we were in and kept going. When we got half way across the next one he asked if I was going to shoot or if I was chicken. I stopped, and ranged the target. 597. He said he couldn't even see it. Got my rifle, and down on my belly. Wind was 1mph right to left. I dialed 1.5Mils U and .1Mils R and let one fly. Then another. We drove back to the target and all he had to say was "Can you teach me?".
View attachment 168233
I explained to him that the fact they hit right beside each other was irrelevant. What matters is the vertical. I would have also been happy if they had been 2-3" apart with no vertical. This is a good load. Once I finish load development in a hunting rifle I don't shoot groups any more with that load. Just a cold bore and a follow up. Target is 1" squares, and his rifle does not shoot this well @100. He was utterly amazed. I told him it is really no big deal, and not really that hard to do. It does take patience and attention to detail.

Hey you Made a convert out of your friend good job

 

[Dean2]

The previous advice on squaring neck's, prepping the brass properly and making sure you are loading concentric ammo, works on all guns. From there what works in one gun doesn't always work in another. Work up a good accurate load, settle on COAL/jump etc. FL 10, neck size 2/3s of the neck length on 10, use the same exact load. Shoot them at 500 yards. Do this 3 times on different days without changing anything else. You will now know for yourself, with that specific gun, which works better.

That said, I neck size all my hunting ammo on my 2 main hunting rifles because that gives me the best accuracy with those two guns, but whether factory, FL or neck sized I make sure to cycle all ammo through the giun prior to hunting with it to make sure it feeds properly.

 

[bigedp51]

Below Kevin Thomas who worked in the Sierra Ballistic Test Lab and now shoots for Team Lapua USA.
Click on image to enlarge

 

[Beluebow]

Does one method end up with bullets better centered in the bore when fired? If so, why?

Does it matter after a bullet travels down a 30" barrel?

 

[Orange Dust]

Hey you Made a convert out of your friend good job

Yes.we are going to see what we can do with the rifle he has now when it warms up a little. I have dies and components to work on it.

 

[misterc01]

IMHO the case prep is critical. Goal: consistent as possible cases. I start with fire-formed cases and go from there. Given you have consistent cases, consistent powder throw, consistent seating at the depth YOUR rife likes for EACH bullet you fire is predictable.. So, I measure my cases, trim or turn to get them consistent and so on and I neck size. I finish with a Hornady concentricity gauge, straighten as necessary to no more than .002 concentricity, most end up pretty much dead on. I use a 14-step checklist with 43 sub-steps for my ammo prep. I follow it EVERY TIME, checking each step off before proceeding to the next. So I can make sure I have covered everything. And as I learn more, it gets longer. And each step stacks on the ones before, so anything off at any steps will affect the final round. So the goal is as consistent "as possible."

 

[freddiej]

Does one method end up with bullets better centered in the bore when fired? If so, why?

there are going to be so many people stating neck only and full length. it's what ever has worked best for them. there is a third choice the one I use

I personally full length size with a twist. I find out how much excessive headspace I have then I set my dies for 0.001" to 0.002" under that excessive length and use that. you are still making each and every round for your specific gun. this goes along with setting the "jump" of the slug for optimum accuracy for your gun. You still need to label the box of ammo specifically for your gun and it's preferred recipe for ammo. full length sizing in this manor will ensure if your ammo gets something on the case that the ammo will still go in the chamber. neck only sizing has failed to go into the chamber and still needs to be full length sized every 3 to 4 resizings to fit back into the chamber.
this post could be a mile long but I am not going to bore everyone with lots of technical things. suffice to say, if you keep the brass concentric in the chamber, the slug concentric to the bore, and keep a little wiggle room for something unforeseen to get into the chamber with your ammo, your hunting ammo will be more reliable and as accurate as you can get it. only bench rest allows for you to clean the brass and chamber when the bolt does not close the first time. in the field you could miss a buck of a lifetime or your gun could save your life from a charging animal. discretion is all yours when you load and prepare for the unexpected.
Just my 2 cents worth in a very heated and debated subject.

 

[Orange Dust]

This is what i do, right or wrong, loads some fine ammo with very little runout. All brass is fully prepped and sorted. This includes skim turning necks cleaning up an average of 50% of the neck. Cases are sized with a forster f/l die with the expander removed. They are expanded with a mandrel die and loaded with a micrometer benchrest seater. This is the best i have ever done with a press. I've only been able to do better with an arbor press and hand dies made to fit the chamber. There may be better ways to do this that i dont know, but this will load very good ammo for hunting.

 

[Mram10us]

I keep hearing, "the competitive guys full length size". I find the general statement somewhat misleading or overly broad. The statement suggests the comp guys are the same as the guy usually asking the question, as though it is apples to apples. Its not!


Yes, I full length on all hunting and some precision rifles. However, I like the bench folk I know, had a reamer ground to match the dies used or dies made to match the reamer used.

The very idea that you can shoot rounds in just any chamber and then FL size with just any SAAMI die and then get the magic dimensions that produce a combo that shoots bug holes is unrealistic. Although I will concede that uncle Jethro might have an O3-A3 that shoots bugholes.

In the real world the guys who are shooting for excellence have $$$$$ tied up in a rifle/scope/gear. To think they just threw a dart to buy dies is ^*+#~!

we all probably have our own thoughts on max growth tolerances for body to chamber, OA growth, as well as throat growth. I don't know any serious shooter who FL sizes regularly unless they have dies matched to their chambers or chambers matched to their dies. And unless all the stars align, SAAMI dies are not Going to do it. THE difference between a SAAMI FL die and a SAAMI Reamer when you have the max spec on the Chamber and the min spec on the die can be huge in body OD and length growth. Add to the built in differences inherent in the chambering process/set up from one smith to the next and cases can grow .010+ in length from FL SAAMI sizing to shooting and similar body growth. Ain't nobody shooting 1/8 to 1/4 moa or less with cases growing .008 or more (in any direction) with each firing.


I agree with everyone who says Prep-Prep-Prep. Doesn't matter how good your chamber/die relationship is, Garbage in. Garbage out.

In short, why are you disagreeing with my statement?

 

[BigJohnH]

Full length sizing returns the brass to a factory state if the brass you are reloading was SHOT IN THE WEAPON YOU ARE RELOADING IT FOR THEN AND ONLY THEN DO YOU NECK SIZE! As to your question being the round was fired in your weapon yes neck sizing will align the bullet better but only because the brass is fire formed to your weapons chamber.

 

[Bart B]

Does it matter after a bullet travels down a 30" barrel?

Yes. Bullets are least deformed when entering the chamber throat as straight as possible. That said, even crooked ones indexed the same in the chamber can be very accurate.

7.62 NATO M118 match ammo was notorious for its 7 to 8 thousandths bullet runout. Best accuracy in bolt action test barrels was around 12 inches at 600 yards; near 16 inches in match grade service rifles. Indexing bullet runout high point repeatable down to about 12 inches in M1 and M14 match grade versions.

Too bad they used 3 or 4 different lots of bullets in each lot of M118 ammo.

 

[9x23w]

In my limited experience I would say consistency is a big contributor towards accuracy. Your ammo is not consistent when you neck size.

Also many of the techniques mentioned here are out the window when you are dealing with ammo to be used for multiple firearms.