Questions about neck turning, minor issue

[gamestalker]

I started turning my necks, .270 in and 7mm RM nag for now. But I'm having a little issue with .270. win..

No problems when fired. But when I turn them, I have the pilot to just barely cut into the neck shoulder junction, same way I'm doing 7 mag.. But as soon as it gets up to the the shoulder, it isn't feathering, it's leaving a more pronounced ridge, and I'm pretty certain I'm not getting to far into the shoulder.

I'm using the K&M with the carbide pilot and cutter, and the cutter is orientated correctly, cause it does feather a little bit, but there's a pronounced finishing line ridge at the shoulder neck junction, just not as feathered as the 7 mag brass comes out.

So my question, has anyone had a problem with the angle of K&M cutters being out of spec where the cutter is supposed feather into the shoulder / neck junction? Or am I just not adjusting far enough into the shoulder maybe, though I don't think I am. I also don't think I'm taking too much material off, of anything, I might not be removing enough. Finished neck thickness is measuring .0146" all the way up to the shoulder. Any less than that, and the neck is still uneven, and I have visible low spots, so I'm definitely at the minimum necessary to get uniform thickness.

Should I try taking off another .0001" or .0002", would it make any difference regarding this problem?

I'm using a dial indicator to obtain accurate measurements, and also measuring OD before and after with a dial caliper, both measuring tools / methods correlate with one another.

GS

 

[Walkalong]

The "feathering" effect will be different with different shoulder angles. The ridge will iron out.

 

[Bart B.]

I don't see any need to cut into the shoulder at all. That part of the case usually doesn't touch anything when the round is fired.

I've seen no improvement in accuracy with anything less than .002" spread in neck wall thickness; good cases have that. There's more important stuff to do. Sierra Bullets does no prep on cases used to test their stuff for accuracy. They get sub half MOA with all their match bullets' 10-shot ten-shot groups at 200 yards. That'll win a lot of benchrest aggregates.

 

[243winxb]

Finished neck thickness is measuring .0146" all the way up to the shoulder. Any less than that, and the neck is still uneven, and I have visible low spots ,

Your not removing enough.

a more pronounced ridge

I would not cut into the shoulder. But then, what do i know, i use a Lyman turner.

 

[Bart B.]

If the chamber is a factory or SAAMI spec dimension, you don't need to remove brass until all of the outside is turned without any visible low spots. As long as the neck thickness varies all the way around less than about .0015", that's good enough.

If all case necks are turned down to show no low spots, your fired case sizing die may not make case mouths small enough to reliably hold bullets in place until fired. And case life is also reduced. Nothing's gained with zero spread in neck wall thickness unless your largest test groups are about 2/10ths MOA.

 

[murf]

the whole reason to turn case necks is to have the same thickness (neck tension) for all cases, not a uniform thickness on each case. the important thing here is consistent case neck tension. making all cases .012" thick (or whatever thickness you choose) is the goal. as bart and the others have said, don't worry about not getting material off all the way around the neck, the sizing die is only going to hit the shinny spots anyway. consistent neck diameter on all cases - consistent neck tension on all cases.

murf

 

[IWAC]

Neck turning? Well...yes, ummmm...Rule of Thumb...as one gets older, turning your neck becomes more of a chore...arthritis, you know. But, done carefully, it can minimize problems.

 

[Walkalong]

I would rather buy better, more uniform brass than neck turn for a standard chamber. Too bad Lapua doesn't make .222 Mag brass. For it I do as Bart described, turn just enough to clean things up.

 

[Bart B.]

Uniforming case neck wall thickness to for them to grip the bullet the right amount is a good idea. That "grip" is referred to in the ammo industry as the "release force" needed to get the bullet out of the case neck. Measured in pounds, it can vary from a few to several dozen depending on several requirements of handling, transportation and functioning in the firearm.

It's easily measured with a bullet puller gripping bullets hard then measuring the force needed to pull it out of the case. Figure out a way to fasten a shell holder to a bucket and mount the bullet puller off the edge of a bench top. Affix a round in the puller then dump bullets into the bucket until the bullet comes out. Weight the bucket and its contents.

Ammo's most accurate with the acceptable minimum release force and smallest spread across the lot of ammo.

 

[gamestalker]

Deleted

 

[gamestalker]

I'd really love to use Lapua, but I don't see that they make 7mm RM or .270 brass. So I'm finding the best I can do is anneal and turn what ever I can get my hands on.

Obviously, one can't transform commercial grade brass into Lapua, but it can be improved to some degree by taking the time to anneal and turn, this is all I'm trying to accomplish. And also of note, it would be ridiculous to assume one can transform a production grade rifle into a custom SAAMI spec blue printed rig as well.

That said, thanks for the advice, I'll apply any and all advice from those willing to assist me while I progress through the learning curve, I do appreciate it. The you Tube video's vary by opinion, as well as detail. Some say don't get into the shoulder at all, while others say barely take some off the shoulder neck junction, so I'm trying both versions to see what, if any difference it makes.

OTOH, when I get the rest of my money together for my up coming custom build, I'll at least I'l have a bit of experience under my belt and some of the bugs worked out. I don't see any harm in expanding one's skill and knowledge within this hobby, especially with the team of experts here that are willing to help me along. This is one of the primary reason I've been conducting some before and after tests regarding consistency of neck tension. And for what it's worth, I also thought that by sharing those results here, it may provide some level of insight for someone else.

GS

 

[gamestalker]

Hey Bart, did you happen to read my post about "The potential improvement of annealing and turning" a couple days ago? If not, take a glance, I thought it was a innovative method, very similar to your method, just a little less cumbersome maybe.

I used a trigger gauge to measure the pulling force of non annealed, non turned brass, compared to annealed and turned brass. I used the same brass and measured bullets of identical diameters and bearing surfaces. Even though it may not be the most accurate means of measuring neck tension, the results were pretty inspiring I thought. I've also used the same method to measure set back on rimless cartridges such as 9mm and .40 cal., I thought that provided some pretty interesting insight also.

I'm really enjoying this new advanced method of reloading, but then again, I just enjoy reloading and all that goes with it. Can't wait to get my custom rig, then I can get even more serious about this, and other advanced aspects of this awesome hobby.

GS

 

[fguffey]

Uniforming case neck wall thickness to for them to grip the bullet the right amount is a good idea. That "grip" is referred to in the ammo industry as the "release force" needed to get the bullet out of the case neck. Measured in pounds, it can vary from a few to several dozen depending on several requirements of handling, transportation and functioning in the firearm.

Measured in pounds, I have always called it 'bullet hold', I could measure bullet hold in pounds but neck tension? I have tension gages, a most awkward tool when measuring bullet hold. My tension gages measure in pounds.

F. Guffey

 

[spitballer]

Is it necessary to go that far down? With a tapered neck sizer bushing I don't contact much more than about 1/16", but that's for .223.

 

[fguffey]

Is it necessary to go that far down? With a tapered neck sizer bushing I don't contact much more than about 1/16", but that's for .223.
__________________

Then there are others that want to uniform the thickness of the neck. I would choose to ream the neck, that requires outside case neck support, that gets expensive. And I do not have that problem with the shoulder/neck juncture and do-nuts. When I ream the inside of the neck I have no choice because in the scheme of case forming I create donuts.

F. Guffey

 

[243winxb]

Neck Turning

So my question, has anyone had a problem with the angle of K&M cutters being out of spec where the cutter is supposed feather into the shoulder / neck junction? there's a pronounced finishing line ridge at the shoulder neck junction,

http://www.accurateshooter.com/technical-articles/neck-turning-tool-cutting-tips/

The answer here is simply to use a cutter tip with a wider angle — 30 to 40 degrees.

I know nothing, i just Google good.

 

[gamestalker]

Thanks for the link 243winxb.

Based on that, I guess I think I'm ok then. I'm using the K&M carbide cutters, and I'm definitely not getting into the shoulder that far, not even close to that far. If anything, I'm guessing I must have some serious doughnuts, cause there's a lot of material coming off right at the neck shoulder junction, which is leaving that sharp ridge I mentioned. And I can actually see the doughnut, it's pretty pronounced on some of the brass.

Thanks
GS

 

[Walkalong]

Donuts form on the inside of the neck.

 

[gamestalker]

Walkalong, do they form up near the shoulder? This is where the brass begins to get thicker when I'm turning, so obviously where more material comes off, right up to the shoulder.

Am I understanding this correctly?

Thanks

GS

 

[243winxb]

Donuts are at the neck/shoulder junction, correct. This is measured as a thicker area of the neck. Sizing with a bushing die will move the donut to the inside of the neck, if no expander is used. An expander/mandrel will move the donut to the outside of the neck where it can be turned off. If the donut is large/thick, it can be reamed out while being held in a special die for the purpose, mostly when forming a wildcat cartridge.

 

[gamestalker]

Right, I am using a mandrel, so ya the doughnut is on the outside. I guess that explains why I have more material coming off as I get into that area of the neck. I just wanted to confirm with those experienced with this, as that is what I'm experiencing.

Thanks Walkalong, really appreciate the advice. I think it's all going well thus far, I just needed some expertise to support my observations.

GS

 

[243winxb]

My Lyman needs brass to be fl sized & expanded in a standard die before turning. Some benchrest shooters turn fire formed brass. Turning while the mandrel is inserted has to be the better method. Lets see what Walkalong has to say.

 

[Walkalong]

Donuts are at the neck/shoulder junction, correct. This is measured as a thicker area of the neck. Sizing with a bushing die will move the donut to the inside of the neck, if no expander is used. An expander/mandrel will move the donut to the outside of the neck where it can be turned off. If the donut is large/thick, it can be reamed out while being held in a special die for the purpose, mostly when forming a wildcat cartridge.

Yep, the dreaded donut is supposed to be made by not cutting far enough into the shoulder. Problem is, it only delays the donut if you fire the cases enough and at enough pressure. Other problem is how far into the shoulder before we create a weak spot. Since we are sizing necks from the outside the donut ends up on the inside as the thick spot moves forward. If you are not seating deep enough to contact the donut it isn't an issue, but with many standard guns we will be. You can always carefully ream the donut away. Using an expander won't move the donut completely to the outside.

Yes, we would fire form .220 Russian, neck turn with the mandrel inside and there would be no donut, but it will show up after the next firing/sizing or two if not done right, and sometimes later anyway. It starts as excess thickness in the shoulder neck junction and moves forward. Since we are always sizing from the outside, it remains as a donut on the inside.

So, are your donuts showing as a little bump in a ring around the inside of the neck yet, or were you referring to the ridge on the outside as I thought you were?

 

[Bart B.]

Gamestalker, yes, I read that post about The potential improvement of annealing and turning.

I've never annealed a case neck. Never saw any need to. I minimally size fired bottleneck rifle case necks in gelded full length sizing dies; no balls to work harden and bend case necks. Their necks are honed out to different diameters depending on case neck wall thickness for 30 caliber cases to about .002" smaller than loaded round neck diameters.

There's several opinions as to what causes donuts at the case mouth/shoulder juncture. I've not been concerned with them as my rifle cases don't have bullet heels seated deeper than they are in the case neck. No memory of even looking for them. But my 30 caliber cases fired and full length sized 30 or more times with max loads don't seem to have any accuracy problems. My philosophy; if there's no problems with your reloads, don't try to find one.

 

[gamestalker]

Walkalong, you've really helped me address the doughnut. Unless I'm using a particularly heavy / longer bullet, which I really don't, the heel rarely gets into the doughnut. So that said, I really don't need to turn all the way up to the shoulder or slightly into it, as it were then, am I correct? this being the case, I can simplify my turning process, thus reduce the risk of getting too far into the shoulder.

Bart, I understand the why fix something that's not broken approach, and analogy, and agree, why bother if there's no need to do it. However, and more often with 7 mag. and 300 WM brass, I've had splits develop right at the shoulder / neck junction, which really irritate the tar out of me. And it usually happens on the first or second loading with new brass. I get the occasional issue with .270 also, but not nearly as often as with the belted mags.. So annealing has been something I've put off for many years, though I did try it back in my earlier years, but I didn't know what I was doing, thus the information highway wasn't what it is today, so I gave up. So annealing is a process that may produce a positive effect for me, or more specifically, solve a problem. Regarding accuracy, I don't know what will change, if anything, but I am expecting to reduce the neck splits by annealing.

Thanks again for the expertise, I really do sincerely appreciate it.

I'll get back with any changes all this additional case prep may produce. But it may be several weeks, as I'm replacing some glass, and at least one trigger, and then we'll see how it goes.

GS