So how important is neck tension?

[jimmymac]

the 6ppc is an inherently accurate round. i see no reason that your rifle shouldn't shoot in the 1's and 2's with a little work. you may see that fade some after that barrel heats up.

kind of what i expected. on your next batch of brass i would.not turn the necks so much. you really only want about .003 clearance between loaded round and chamber. you far exceed that. thicker necks will give you more neck tension with a larger bushing.

6ppc likes them jammed and hot.

now what is the barrel twist. those 60 grain bullets like 13.5 twist. for heavier you want a 12 or faster

With all due respect, I seriously doubt that gun will shoot into the 1's and 2's no matter what is tried. Sako's are nice, but the fact remains it's a factory sporter and will perform accordingly. If the OP starts chasing his tail in pursuit of 2's he'll end up in load development mode for the life of that barrel and in the end will never get there.

 

[geraldgee]

Has your attention been devoted to load development solely? Have you had the rifle been properly bedded? Trigger work? While reloading will certainly increase your level of accuracy, you need to help your rifle help you achieve your goal of .5 MOA. While bedding isn't a guarantee of smaller groups, if done correctly, it will improve your overall consistency as will a properly tuned trigger.

Good luck in your pursuit.

 

[msinc]

With all due respect, I seriously doubt that gun will shoot into the 1's and 2's no matter what is tried. Sako's are nice, but the fact remains it's a factory sporter and will perform accordingly. If the OP starts chasing his tail in pursuit of 2's he'll end up in load development mode for the life of that barrel and in the end will never get there.

Yeah, I gotta agree....the fact that it's a Sako {which are typically not noted for extreme accuracy anyway} aside, there is no cartridge that is so "inherently accurate" that shooting in the 1's and 2's is a given, with or without "a little work". If there was you can best believe that would be the only thing anybody bothered to build/shoot!!!!

But whether you can see any difference depends on you and your rifle. With a full-blown benchrest rifle and a proficient shooter, neck tension matters.

I also agree, and I have to say that if neck tension is sooooo "HUGE", so big a deal as some of you claim...why is this statement true???? If it depends on you and your rifle, and it has to be a "full blown benchrest rifle and you have to be a "proficient" shooter to begin with to even see it then sorry, that is not what I call "huge". Not by a long shot!!! Neck tension can make your groups a little better, it can even get you to the winners circle, but with this particular rifle and please don't take this wrong but this shooter and the type of shooting he's going to be doing.....neck tension is a distraction that maybe one day should be explored, but still should be way down on the list. Personally, I'd be more worried about bullets that will group, especially these days. Telling this guy he should stress over a benchrest "trick" that may or may not get your groups a slight bit better when you cant hardly find or buy bullets that group under an inch is ridiculous.

Edit: it's kind of like deficating down both legs because you don't have Lapua brass to shoot..."oh my god, no!!!!!!!" Lapua brass is fine, but some of these people act like there's no sense going to the range without it. If you are loading it with Hornady, Nosler or Sierra bullets you would probably be just as well off and shoot just as good {if you consider it good} if you reloaded some of that steel cased Russian junk that they paint brown and sell cheap at gunshows by the metric schidt ton.
There was a time when I shot some fantastic groups with Sierra bullets...but it aint happenin' today!!!

 

[mikecr]

Should not have turned the necks for .270 chamber.
Your neck clearance as turned is 8thou at least!

 

[Steve Ladino]

I'm in the process of working up loads for my Sako sporter 6 PPC and have tried two powders (H322 and VV 133) and two bullets (Bart's and Watson 68-gr.) now, and have varied seating depth and powder-charge weight in my quest for best accuracy. With all these factors being varied, there are a lot of variables--and resulting combinations--at work in the process. I'm loathe to add still another variable--neck tension--but am wondering whether perhaps I should. All of my loads so far (with by now about 150 rounds down the tube) have been with .002" neck tension (if that's how we measure it)--by which I mean I have sized the necks down (with a Wilson chamber-type neck-sizer) to .002" less than the OD of the loaded rounds' necks. More specifically, I've used the .260" bushing for the OD of loaded necks of .262".

So here's my question. Can I realistically expect any change in performance (group size) by trying some loads with .003" neck tension--i.e., using the .259" bushing for the OD of loaded necks of .262"? Adding still another variable into the process adds to the complexity of the load-development process, but if there's some chance that different results may be expected by varying neck tension, I guess I should try this. I've read that certain powders work better with greater neck tension than do some other powders. Is there enough here to try this, or am I likely to see no change in performance?

I don't think its been mentioned in the above recommendations but along with neck tension, which is important the condition of the neck material as well should be kept healthy by way of annealing on some sort of strict regiment either every two three or four loadings or more or less.

 

[Laurie]

Should not have turned the necks for .270 chamber.
Your neck clearance as turned is 8thou at least!

Yes, that was very much my thought too. With the rifle chambered for the 'cooking' 6PPC-USA factory round you're creating a lot of clearance here. If nothing else, it's going to reduce your brass life through the extra movement in firing / resizing. It's not that a lot of clearance guarantees poor results - I've used 1980s vintage 160gn weight Norma 308 Win cases with their very thin necks (some down at 0.011-0.012") extensively in a minimum-SAAMI chamber FTR rifle. Despite having similar clearances as you're creating, I obtained very good results. Nevertheless, that sort of mismatch was living with a given set of components not created out of choice - I'd never turn my Lapua 'Palma' case necks down to create it.

On the basic question, I found out the hard way that the full-house non CIP/SAAMI version needs a lot of neck tension to work with N133 in my brief stint with a proper bench-gun, but I'm not sure that this guarantees a PPC-USA set-up works to the same rules. I was most intrigued too to read the results of Applied Ballistics LLC's neck tension tests on various cartridges in Bryan Litz's new book 'Modern Advancements in Long Range Shooting Volume II' which showed no discernible differences through a range of tension levels in a variety of cartridges. True, Bryan's people were looking solely at the MV ES/SD effects, not on group sizes, but even so it is a challenge to one of the great tenets of precision shooting beliefs and practices.

 

[Richard Coody]

well i see no reason that a sportsters contoured barrel could not be as accurate as any other at least for the first few shots. with good load development and great attention to detail in your reloading practices your rifle may suprise you.

 

[Tim Singleton]

well i see no reason that a sportsters contoured barrel could not be as accurate as any other at least for the first few shots. with good load development and great attention to detail in your reloading practices your rifle may suprise you.

To shoot in the ones it takes a shooting system
It's not just done with good loading practices. A rifle purpose built for competion a front rest and rear bags rifle and wind flags make up a system
With all those things teen groups aren't so easy

 

[Webster]

I'm in the process of working up loads for my Sako sporter 6 PPC and have tried two powders (H322 and VV 133) and two bullets (Bart's and Watson 68-gr.) now, and have varied seating depth and powder-charge weight in my quest for best accuracy. With all these factors being varied, there are a lot of variables--and resulting combinations--at work in the process. I'm loathe to add still another variable--neck tension--but am wondering whether perhaps I should. All of my loads so far (with by now about 150 rounds down the tube) have been with .002" neck tension (if that's how we measure it)--by which I mean I have sized the necks down (with a Wilson chamber-type neck-sizer) to .002" less than the OD of the loaded rounds' necks. More specifically, I've used the .260" bushing for the OD of loaded necks of .262".

So here's my question. Can I realistically expect any change in performance (group size) by trying some loads with .003" neck tension--i.e., using the .259" bushing for the OD of loaded necks of .262"? Adding still another variable into the process adds to the complexity of the load-development process, but if there's some chance that different results may be expected by varying neck tension, I guess I should try this. I've read that certain powders work better with greater neck tension than do some other powders. Is there enough here to try this, or am I likely to see no change in performance?

Why don't you try several neck tensions yourself and see what difference it makes. You only need 10-15 shots if you have good shooting skills. You will get 50 replies on this website and everyone means well. Not to insult the replies. Serious BR shooters have custom reamers and dies, no turn necks.

 

[DJSBRS]

Why don't you try several neck tensions yourself and see what difference it makes. You only need 10-15 shots if you have good shooting skills. You will get 50 replies on this website and everyone means well. Not to insult the replies. Serious BR shooters have custom reamers and dies, no turn necks.

Assuming all things equal, would more neck tension raise pressure or FPS?

DJ

 

[Tim Singleton]

I assuming all things equal, would more neck tension raise pressure or FPS?

DJ

This is just my experience
So take it for what it's worth.
Increase in neck tension and no other change doesn't show anything on target 100-200 yards
Now increase neck tension combined with jaming further into the lands that the heavier neck tension allows increases pressure

 

[DJSBRS]

This is just my experience
So take it for what it's worth.
Increase in neck tension and no other change doesn't show anything on target 100-200 yards
Now increase neck tension combined with naming further into the lands increases pressure

Does an increase of 20 to 25 FPS show up on a 100-200 yard target?

 

[Richard Coody]

To shoot in the ones it takes a shooting system
It's not just done with good loading practices. A rifle purpose built for competion a front rest and rear bags rifle and wind flags make up a system
With all those things teen groups aren't so easy

well i am pretty close with my home made savage.

 

[Tim Singleton]

Does an increase of 20 to 25 FPS show up on a 100-200 yard target?

In my experience no it will not
My gun in tune can swallow 40 plus fps

 

[DJSBRS]

In my experience no it will not
My gun in tune can swallow 40 plus fps

What does 40 FPS measure at 600 yards or 1000 yards?

So, if the neck tension is the same whether .002 or .004 , does it really matter and measureable on the target as long as all other are the same?

 

[Tim Singleton]

No idea at 600-1000
I'm just talking about a PPC at 100-200

 

[Brians356]

How important is neck tension? Some here will roll their eyes, but FWIW I harken back (again) to Virgil King's indoor accuracy work. For Virgil, neck tension was the most critical aspect of the cartridge itself. Shooting a 22 PPC, he said he never weighed powder charges, he threw them (with a good Culver conversion or Belding & Mull measure) but said he didn't see any change in his group sizes as long as the charges were within plus/minus 1 whole grain!

Read this essay, especially the part about how King prepped his cases, in particular how he obsessively tuned neck tension. Also note that he seated his bullets using a Wilson inline seater by hand (no arbor press) for maximum tactile feedback.

http://www.angelfire.com/ma3/max357/houston.html

All this suggests is that, for world-class benchrest accuracy, neck tension is worth obsessing about. But it also suggests that even for a good long-range hunting rifle, certainly a tack-driving varminter, neck tension is probably worth your attention.
-

 

[BoydAllen]

Last weekend my friend Gary Ocock shot a 100yd rail gun aggregate of five five shot groups in a fun match conducted exactly like a sanctioned one. It was .0840, well under the records of both the NBRSA and the IBS. Previously he had tested his particular setup (barrel, chamber, bullet) to see whether there was any advantage to using more neck tension. There was not, so he stayed with the bushing that he had been using for surplus 8208 which gives him .001 neck tension. I have been a big advocate of lots of neck tension for the typical .262 chamber neck 6PPC based on my results and those of others as well, but this case was an exception, which makes an important point. Do your own testing. What works for some other fellows may turn out differently for you. BTW the load for the smallest four groups in that agg. was very hot, and his bullets were seated at jam. He shoots his own BT bullets.
DSC00569 by boydallen, on Flickr

 

[Shynloco]

Boyd,
That's cheating....LOL! But it is one helluva target.

A;ex

 

[Ggmac]

I haven't read the entire post , but in my personal lifelong 6 PPC guest for accuracy , WHEN IM HARD JAMMED ! NECK TENSION MEANS LITTLE !