I bought a sinclair N1000 neck turner. I was using it earlier on some junk brass to get the feel for it. I know you want to just take enough off so that you are on the level of the lowest spot. So how thin can you get the neck wall before it is unsafe? On the old brass, the neck was at about 13 hundreths of thickness before turning. After it was about 11.5 hundreths. I assume pressure of the cartridge has a alot to do with it too.
Neck turning. How thin is too thin?
- Thread starter JWV
- Start date
Re: Neck turning. How thin is too thin?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JWV</div><div class="ubbcode-body">I bought a sinclair N1000 neck turner. I was using it earlier on some junk brass to get the feel for it. I know you want to just take enough off so that you are on the level of the lowest spot. So how thin can you get the neck wall before it is unsafe? On the old brass, the neck was at about 13 hundreths of thickness before turning. After it was about 11.5 hundreths. I assume pressure of the cartridge has a alot to do with it too. </div></div>
I've measured 223/556 brass at .0105" and it's fine. All that'll happen is that it will split, which happens often if you shoot enough.
Like you said, you just want to clean up 3/4 to 4/5 of the neck and then only remove the high spots. From what I gather, necks tend to split at the thinnest part around their circumfernce, so you're actually making things stronger, even though you're thinning the neck walls.
Chris
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JWV</div><div class="ubbcode-body">I bought a sinclair N1000 neck turner. I was using it earlier on some junk brass to get the feel for it. I know you want to just take enough off so that you are on the level of the lowest spot. So how thin can you get the neck wall before it is unsafe? On the old brass, the neck was at about 13 hundreths of thickness before turning. After it was about 11.5 hundreths. I assume pressure of the cartridge has a alot to do with it too. </div></div>
I've measured 223/556 brass at .0105" and it's fine. All that'll happen is that it will split, which happens often if you shoot enough.
Like you said, you just want to clean up 3/4 to 4/5 of the neck and then only remove the high spots. From what I gather, necks tend to split at the thinnest part around their circumfernce, so you're actually making things stronger, even though you're thinning the neck walls.
Chris
Re: Neck turning. How thin is too thin?
I don't know that it is so much of a safety issue as an accuracy issue. Too thick for a tight neck is a safety issue as the neck won't have room to release the bullet. Kaboom! A thou and a half per side is good for that.
If you don't have a tight-necked chamber, you really want the neck to be as thick as feasible while still turning away the high points. What I do is measure several hundred cases in 4 places on the neck. I figure out a thickness that is thinner than the thinnest point on 95% of my cases and turn to that. That is pretty anal... but I will still end up with low spots that I didn't measure.
The reason you want that dimension as thick as possible is because you want support for your cartridge. A thick neck dimension will help to align your cartridge in the chamber... or at least I would think that it would. That said, there are plenty of folks who take off quite a bit of brass who do just fine.
German Salazar standardized to 12.5 thou because he loads a lot of different brass and 12.5 works for his thinnest brass (presumably WW). I do 14.4 thou for Lapua and end up culling out the brass that doesn't make the cut (no pun intended). I am way too anal on this, but I like to see .1 thou or less of variation within the neck... and this number is very achievable with good turning technique. Whether this degree of consistency matters or not is another story. The fact that I can get it means that I try to get it every time.
Oh, and one other consideration... turning too thin will cause you to work your case neck more as the neck has to expand farther to seal the chamber. All that working will cause the brass to harden faster and split faster. This is not so much a safety issue as you should be inspecting for this anyway, but economically, it will mean you will get fewer firings per casing.
I don't know that it is so much of a safety issue as an accuracy issue. Too thick for a tight neck is a safety issue as the neck won't have room to release the bullet. Kaboom! A thou and a half per side is good for that.
If you don't have a tight-necked chamber, you really want the neck to be as thick as feasible while still turning away the high points. What I do is measure several hundred cases in 4 places on the neck. I figure out a thickness that is thinner than the thinnest point on 95% of my cases and turn to that. That is pretty anal... but I will still end up with low spots that I didn't measure.
The reason you want that dimension as thick as possible is because you want support for your cartridge. A thick neck dimension will help to align your cartridge in the chamber... or at least I would think that it would. That said, there are plenty of folks who take off quite a bit of brass who do just fine.
German Salazar standardized to 12.5 thou because he loads a lot of different brass and 12.5 works for his thinnest brass (presumably WW). I do 14.4 thou for Lapua and end up culling out the brass that doesn't make the cut (no pun intended). I am way too anal on this, but I like to see .1 thou or less of variation within the neck... and this number is very achievable with good turning technique. Whether this degree of consistency matters or not is another story. The fact that I can get it means that I try to get it every time.
Oh, and one other consideration... turning too thin will cause you to work your case neck more as the neck has to expand farther to seal the chamber. All that working will cause the brass to harden faster and split faster. This is not so much a safety issue as you should be inspecting for this anyway, but economically, it will mean you will get fewer firings per casing.
Re: Neck turning. How thin is too thin?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JWV</div><div class="ubbcode-body">I bought a sinclair N1000 neck turner. I was using it earlier on some junk brass to get the feel for it. I know you want to just take enough off so that you are on the level of the lowest spot. So how thin can you get the neck wall before it is unsafe? On the old brass, the neck was at about 13 hundreths of thickness before turning. After it was about 11.5 hundreths. I assume pressure of the cartridge has a allot to do with it too. </div></div>
IMO,The biggest consideration is how much neck expansion there is on a fired case.For instance if you already have 6-7 thou expansion on virgin case then just clean the neck up as little as you can.That's quite a bit of neck expansion and the result will be early neck splitting.Or you could buy a neck thickness/concentricity tool to cull the off ones.If you have 3-4 thou expansion then taking off enough brass to clean up the neck isn't unreasonable.
For this reason I've bought my own reamers.The latter ones I've had cut so I can choose to turn cases or not. 1.5 thou expansion for virgin cases or if I do turn cases I just clean them up and I only have 3 thou expansion.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JWV</div><div class="ubbcode-body">I bought a sinclair N1000 neck turner. I was using it earlier on some junk brass to get the feel for it. I know you want to just take enough off so that you are on the level of the lowest spot. So how thin can you get the neck wall before it is unsafe? On the old brass, the neck was at about 13 hundreths of thickness before turning. After it was about 11.5 hundreths. I assume pressure of the cartridge has a allot to do with it too. </div></div>
IMO,The biggest consideration is how much neck expansion there is on a fired case.For instance if you already have 6-7 thou expansion on virgin case then just clean the neck up as little as you can.That's quite a bit of neck expansion and the result will be early neck splitting.Or you could buy a neck thickness/concentricity tool to cull the off ones.If you have 3-4 thou expansion then taking off enough brass to clean up the neck isn't unreasonable.
For this reason I've bought my own reamers.The latter ones I've had cut so I can choose to turn cases or not. 1.5 thou expansion for virgin cases or if I do turn cases I just clean them up and I only have 3 thou expansion.
Re: Neck turning. How thin is too thin?
A lot of good advice,here.Unless you are turning for a tight neck or fitted chamber,all you need to do is clean up between 50-80% of the case neck.The more you remove,the more the case expands and the faster the brass will fail.Back to your question,a friend turns some of his cases to about .008.There is not much need to go this thin,but he is not having any safety issues. Pete
A lot of good advice,here.Unless you are turning for a tight neck or fitted chamber,all you need to do is clean up between 50-80% of the case neck.The more you remove,the more the case expands and the faster the brass will fail.Back to your question,a friend turns some of his cases to about .008.There is not much need to go this thin,but he is not having any safety issues. Pete
Re: Neck turning. How thin is too thin?
Good stuff guys. The reamer that was used to make my 6.5 barrel has a .297 neck. So I don't think there will be a whole lot of expansion going on.
Good stuff guys. The reamer that was used to make my 6.5 barrel has a .297 neck. So I don't think there will be a whole lot of expansion going on.
Re: Neck turning. How thin is too thin?
JWV,
BR shooters use 0.008 to 0.010, but that depends on the BR shooter. Drop a case and it's toast. On .223 I use 0.010-0.011, most Winchester cleans up at this thickness. On anything else, 0.010-0.011 will be toast if dropped or bumped. 0.012 or thicker give the best life. In a factory chamber with Lapua brass I'm usually able to turn to 0.013 or 0.014.
HTH,
DocB
JWV,
BR shooters use 0.008 to 0.010, but that depends on the BR shooter. Drop a case and it's toast. On .223 I use 0.010-0.011, most Winchester cleans up at this thickness. On anything else, 0.010-0.011 will be toast if dropped or bumped. 0.012 or thicker give the best life. In a factory chamber with Lapua brass I'm usually able to turn to 0.013 or 0.014.
HTH,
DocB
Re: Neck turning. How thin is too thin?
I just turned a bunch of 308 winchester brass for practice. I was starting from .0140-.0130 and taking them down to about .0125. That is when all the low spots were completely taken care of. Now, it is time to give it a go on all my expensive Lapua brass.
I just turned a bunch of 308 winchester brass for practice. I was starting from .0140-.0130 and taking them down to about .0125. That is when all the low spots were completely taken care of. Now, it is time to give it a go on all my expensive Lapua brass.
Re: Neck turning. How thin is too thin?
You should be good to go. Now you've got to measure a loaded round and adjust bushing sizes accordingly.
You should be good to go. Now you've got to measure a loaded round and adjust bushing sizes accordingly.
