I re-read a bunch of posts from the last year on neck turning, and the debate about whether it makes a difference for factory chambers was repeatedly debated.

In the latest GUNS magazine there is an article about reloading practices.

The author, Charles Petty did a very controlled test with a Remington 700P in .308.

Basically, he worked up two sets of 50 match grade cartridges, using a load known to produce .75MOA groups. Only variable was one set of 50 pieces of brass were neck turned to "remove the high spots." He says the brass if Federal brand.

Net net, he found a 30% improvement overall with the neck-turned cartridges.

Have any of you factory-chamber-neck-turnin' naysayers done a controlled test of this type?

Would buying Lapua brass and using one of the tools to measure case wall thickness variation, and then sorting the brass produce results equal to "cleaning up the high spots" with lesser brass? On that subject, what is the best tool for measuring case neck wall thickness/variation, especailly for someone pressed for time?

Thanks

Roger

I don't neck turn...not because I don't believe it would help the gun shoot better. But because a 30% improvement in accuracy in any sub MOA rifle I own is basically meaningless. I hunt and I compete in HP rifle matches at ranges from 200-1,000 yards. Basically, that degree of improvement isn't worth the time and trouble as it doesn't buy me anything in terms of practical results downrange...on either animals or any HP rifle target.
Some may say that the added degree of accuracy neck turning affords a shooting system gives them more confidence afield. Such people are delusional.
If all you want to do is tinker with your loads and rifle that's fine. I'm more pragmatic/practical in my approach to shooting and hunting and once I find a decent load...not necessarily the most accurate load, I generally load several hundred and in the case of my competition ammo, thousand of rounds, and shoot the heck out of it and work on improving my skills. So I know what will happen to a given load at 400 yards in a 10 mph crosswind. That's more important to me instead of eeking out the last bit of mechanical accuracy from a given cartridge/rifle.

The man from Kentucky hit the nail on the head dead center...

In a factory chamber there is enough slop without adding to it.

I outside neck turn for one rifle and it has 0 tolerence chamber and neck, and won't chamber a round without neck turning...It's a 6x45.

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

I'm one of the delusional ones that does neck turn. Its a one time affair and I don't neck turn to fit the chamber; but rather, to clean up the high points on the outside of the neck. And it is somewhat subjective with me in that I want my cut to remove 75-80% of the outside of the case neck.
One thing I don't do, (this will bring shrieks) is weigh cases. Once the necks are cleaned up, any weight variance is academic because you don't know where the weight is. Its certainly not in the neck so what difference does it make? If you have a thick wall on one side of the cartridge, it may affect accuracy. Does it make it shoot better being paired with another case that is overweight in the web? Not hardly. Load 'em up and shoot 'em and any unexplained flyers, toss 'em.
I do admire the shooter that is so good he doesn't care about a 30% reduction in his groups. Most competitive shooters would paint themselves green and do a squirrel dance between relays to gain that.

Don't mean to be delusional but do you guys toss the brass of the round that went a flyer? I never thought about this, but it would make sense to rid the "Known mutents" if you know it was not your error?

I toss the brass that sent the flyer. True it may be a bad bullet, primer, etc but its a start. By the way, in my post I didn't mean that I reduced the thickness of the neck by 75% but rather I set my cutter so it will remove 75-80% of the surface. (my tongue was in front of my eyetooth and I couldn't see what I was saying.... )

I think neck turning for a factory chamber should be done at a very minimum, as was stated earlier ther is plenty of clearence already. I will say though that anytime I can/could do something to a rifle that decreases the group size by 30% I have one satisfied customer, and he brings many more to the shop.

Beeman,
My observation about my fellow shooters on the HP line is the Masters and High Masters don't spend a bunch of time tinkering with their ammo/loads and generally don't bother with a bunch of benchrest techniques to make their guns shoot better. They spend their time shooting the same load and shooting alot of it.
OTOH, the several clubs I shoot with do have a number of tinkerers. These guys are always trying to find that magic load and rarely come to a match with the same load twice. Almost all of them are expert class shots that never really seem to be able to shoot into Master class. If they spent half the time working on their shooting skills that they spend on a new batch of ammo, turned necks etc they'd probably be pretty decent shots.
Let me put this into a different perspective. David Tubb could take any of my match rifles with my fairly straightforward match handloads (nothing fancy) and win the National HP championship every single year he went to Camp Perry if he could shoot to the potential of my gun and handloads. But he can't. And a .20 MOA improvement in my handloads that might result from neck turning wouldn't change any of that...
Unless its slow fire, I rarely know which case resulted in a flier...and its usually me anyhow. I do spin my 600-1,000 yard ammo for concentricity. At 200-300 yards I've not found that it makes a difference. I save any ammo with more than .001 runout for practice.

Nimrod, I an not truly qualified to comment on precision shooting. My shooting competition would best be discribed as sand lot or semi-pro at best. However, when I was fishing bass tournies, I have won and lost several thousand dollars over an ounce or two. So, to my way of thinking, if you can reduce your group from say 1 inch to three quarters of an inch, it will show up as a more positive position over time. I am also pretty sure that I cannot make a crappy load shoot well no matter how much I practice. Also I will be the first to agree that a whole lot of the "stuff" that precision shooters do is pretty anal and done only 'cause someone else does it or "it can't hurt".

Roger.....the reason to partially neck turn brass for a factory chamber is simply to create a more consistent "pull" or grip on the bullet. and a consistent pull is very important to consistent accuracy...having said that, if you use Lapua brass you will find it to have a very consistent neck thickness and I would be amazed if partial neck-turning would have an impact. Lapua brass is "the best" and well worth the extra money.

Thanks for all the imput, but we seem to have gotten a bit off track.

The previous debates I mentioned above were about whether turning brass for factory chambers would improve accuracy. Many said it would not.

You guys are debating the return on investment versus spending more time shooting. Thanks for that observation. But it's not the question at hand.

Net net, does creating a uniform neck diameter, and having it be the same for all rounds result in better accuracy even though on the initial firing there is "slop" in the dimensions of a factory chamber?

When that bullet releases in a factory chamber the brass is allready away from the bullet in that slop area, so why then would you gain anything by outside ream?? Now in a very tight .001 chamber you must outside neck ream in order to chamber the round and you will have excellent accuracy, but my zero tolerance guns are not for hunting big game...I just cannot see a rational reason to do so, but if you must then have at it, you will be over working your brass and that is a fact.

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

I have no experience with this so take it with a grain of salt. Many insist neck turning for factory chambers is a waste of time since there's already excess clearance. But at the same time, I've never seen them produce data to back up their contention.

Conversely, I can think of two articles, the one you mentioned and another from a Handloaders Digest several years ago where the authors turned necks for factory chambers and improved accuracy was demonstarted. Now even though it's improved, don't expect miracles. You may see a reduction on the order of .3 - .5 MOA, but you'll never see a 1.5 MOA rifle turn into a .3 or .4 rifle simply by neck turning. Also, I would expect that in order to realize these improvements you would need to use neck sized cases and use a good quality seater.

What would really be a useful test is to characterize accuracy degradation/improvement as a function of degree of runout. If one starts with good quality cases where runout is no more than .001, neck turning may not be needed. When runout runs over .003, it's probably pretty safe to say that you'll see an improvement. that's just another guess on my part.

Anyway, if you take the plunge, please report your results so we guessers out here could have some more data to go on.

Martindog

Roger,
In order for someone to know what you are asking they would have to do a controlled study using probably 10 different factory rifles in 3 or 4 calibers using thousands of rounds identically loaded with and without turned necks. The test would have to be under controlled conditions with little room for human error. After all that I'd bet a $1,000 bucks that it would find that neck turning helped in some guns, it didn't make a difference in others. and some actually shot worse. That there wouldn't be a definite trend...
As you probably understand, guns are all individuals. What works for one may or may not work in another. Certainly there are generalizations that can be made. Then again I seem to find as many exceptions as there are rules when it comes to what works in any given rifle/load combination.
I've played with neck turning in lots of guns like my .222 rifles and never could see that it made for consistenly more accurate ammunition. But again, I never did extensive controlled testing. My Sako .222 will shoot .5-.6 all day long. Neck turned cases never have shown they helped in that rifle. My Cooper Varminter in .222 shoots such tiny little groups I simply couldn't tell if it helped or not.
I have proven, with lots of load testing and practice, that concentricity matters at 600-1,000 yards. But like I said, at 200-300 yards the benefits are less evident. In my experience bullet dispersion is only rarely linear but concentric bullets will help flatten that curve...

Well, here's my two cents worth, so take it for what its worth

I have a Remington 40XB-KS in .220 Swift that I purchased NIB at a gunshow. The included factory proof targets showed two groups, one ~0.44, and the other ~0.46, IIRC. I figured this was pretty good for a proof target, especially since I highly doubt Remington did any load work up for this specific gun.

The first 80 rounds or so before I had all my reloading stuff in place for this caliber were Hornady Frontier 40gr moly V-Max factory loads. Guess what? They too averaged a little under 1/2 moa... almost right on average w/ the factory proof targets.

Once I started fiddling around reloading for this gun, I started experimenting w/ powders and bullets, using 50 of those original 80 Hornady cases that I had. I did the 'light' neck-turning thing, cleaning up 80-90% of the neck surface. Didn't sort by weight. From what I had heard, any more was a waste of time and effort in a factory chamber in a factory barrel, even if it was a Remington 40X.

Guess what? While I did have one or two groups that were down to ~0.20" or so (ran out of Berger moly 64gr MEFs, so I haven't been able to expand on testing that load yet), the 'average' for the best groups of each load was, you guessed it, ~0.4-0.5"!!! As a side note, I had some really weird group problems at 200 yds, but whether that was the loads or the screw loose btwn the Peltors remains to be seen.

Next, after consulting w/ a couple of the local accuracy nuts, I pitched the original 50 rds of Hornady brass, pulled out my 2 bags of 100 ea. Winchester brass, and proceeded to do a full workup on each case... neck-turn down to a consistent neck diameter, which constituted a 100% clean up on most cases (but as little as 70% on a few), chamfer, debur, (case length out of the bag was well below minimum trim length, so I'm waiting for a little of the mythical .220 Swift case 'growth'), primer pockets uniformed, flash holes deburred. Finally, I sorted by weight. This in and of itself was one hell of an eye-opener, for other reasons. End result was 50 cases that were w/i less than 1% variance in weight, about as close to 'perfect' as possible. Oh, and before I sorted, I had ran thru and removed the ejector plunger on my bold and fired each case w/ a 'fireforming' load to get them squared to the bolt face w/o any possible influences from the ejector. Loading was done w/ Redding Competition dies, and total indicated runout (TIR) was less than 0.001" for each round. So these cases were about as perfect as it was in my power to make them.

I hate to sound like a broken record, but...

Guess what? Again, the 'best' groups for each load I've tried (and I started almost completely over w/ the new brass) averages... 0.4-0.5"!!!

To say this was an exercise in frustration would be an extreme understatement. The gun is being fired from a solid bench, on a Sinclair front benchrest, protector/bald eagle bags, yada yada. I don't know whether the limitation here is me, or if the gun/barrel just isn't capable of any better than 0.4" consistently. I realize there are people out there that would kill to have a good varmint rifle that averages less than one-half moa consistently w/ factory ammo and not have to go thru the freakin' gyrations, but what the hell!?!

Someone please tell me again, that neck-turning and case weight sorting is supposed to accomplish something, besides waste my time?

Monte

rogerinneb, YES, neck turning in a factory rifle increases accuracy, from .750" down to .600" in Rem 40xb. Less in a Rem. 600 , both in 243 win. The most improvement came when going fron RCBS standard dies to a Redding fl sizing type -s bushing die. Now shooting in the .400"s with 40xb. In the Rem 600 groups went from 1.250" down to .900" neck turned and bushing dies, very little improvement when just neck turning the rem 600.If u neck turn, use bushing dies, or forget neck turning.243winxb

I do neck turn my case necks, even for hunting ammo, if only partially to even out neck walls. Some hunting rifles benefit from it, others are indifferent. But then I'd go a long way to get a mere 10% decrease in group sizes. All in my head, I know...

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Andr�

Based on about a dozen rifles I have paid enough attention to form a conclusion...

It has made an improvement in about a third of these rifles; the other two thirds showed no change.

None of these rifles shot worse with turned necks, so I continue to do it.

However, note that I was merely knocking off the high spots and not removing enough brass to create any appreciable extra slop in the chamber. On this point I agree with Atkinson... however, I have found that as long as the turning is moderate, clearance is not increased much and accuracy improves in some rifles. Most importantly, I've never seen it get worse!

Note that all these were close to MOA rifles. If a rifle shot 2 MOA, I've never bothered keeping the rifle, let alone turning necks for it!

jpb

[This message has been edited by jpb (edited 02-27-2002).]

Thanks everyone!