Neck Turn Length

[abintx]

I've heard and read from various sources, good sources, that case necks should be turned to within .002 of the neck/shoulder junction, to the neck/shoulder junction, and 1/32" into the neck/shoulder junction to prevent the dreaded donut. What's the consensus among the Benchrest community ??? Is there one ??? Thanks!

 

[C.L. Peterson]

Neck Turning

I've heard and read from various sources, good sources, that case necks should be turned to within .002 of the neck/shoulder junction, to the neck/shoulder junction, and 1/32" into the neck/shoulder junction to prevent the dreaded donut. What's the consensus among the Benchrest community ??? Is there one ??? Thanks!

Articles and chapters in books have been written on this subject for ones review. The "conventional wisdom" (what ever that is) has been to cut into the neck/shoulder junction and just "kiss" the shoulder a bit.
This does not prevent the donut but diminishes its size hopefully. Removing/eleminating the doughnut seems a elusive goal for most of us.
With experience in neck turning one reaches a level of comfort with ones technique and end results your comfortable with.
Just one opinion
CLP

 

[Wilbur]

Just turn the neck

Turn it well below where the bullet will seat. Keep a watch on that donut such that it's always below the bullet. That's all there is to this matter...

 

[alinwa]

Well if you DO want to completely eliminate the donut then you can grind your cutter to closely approximate your shoulder but still with some clearance.....in other words so that it hits at the junction first and then feathers up into the shoulder like the center cartridge in the 3-cartridge pic below. The cutaway view attempts to show the transitions.....the one in the picture is too abrupt IMO, I was playing with cutter grinds. As the closeup picture shows, there's a noticeable step in the transition. Any deeper and the result would have bee a thin spot and possible neck separation.

If you'll study the pictures then perhaps they will show what I'm driving at, that the closer that the grind matches the existing radius and shoulder angle the further up the shoulder you can "feather", the better to eliminate the donut.

The donut is nothing more nor less than thicker shoulder brass which is "blown around the corner" when you fireform. Or worst case it's just left there from neck turning. As Wilbur says, as long as you stay away from it you'll have no problems anyway.... BUT, if you play with long bullets and find yourself wanting to plumb the depths, then you'll need to eliminate the donut.

Once eliminated the donut it WILL NOT reoccur if your resizing process is properly adjusted. If you do turn such that you don't have a donut and the donut APPEARS after several firings then this is one of the signs of over-sizing the shoulder. A second sign is case necks growing in length. If you have to "trim to length" periodically then you are over-sizing.

The third sign is the appearance of a grainy,shiny ring at the junction of the case web to body.

The fourth and final sign is case failure, the infamous casehead separation. You can often get away with a bunch of these but once in a while.......... and that ONE time you forgot your glasses......... and you'll remember it.

These pictures don't show it all as I took them to document my steps in setting up a cutter. If I can find a picture of a long feathered edge from a well matched grind I'll post it.

hopefully they'll help someone to understand and visually see what's being accomplished. Also, if you're really looking you'll notice that these cases were neck/shoulder bumped using a button type die. The internal radius of the sized cases shows a ring where the die transitions to the sizing button. The pics were also to illustrate how using a button die to form the neck for turning is not ideal.

A sharply shouldered one piece sizer makes for a more usable neck turning radius.

And to REALLY dial in this process, cases should be fireformed before neck turning.

hth


al

 

[Al Nyhus]

I've heard and read from various sources, good sources, that case necks should be turned to within .002 of the neck/shoulder junction, to the neck/shoulder junction, and 1/32" into the neck/shoulder junction to prevent the dreaded donut. What's the consensus among the Benchrest community ??? Is there one ??? Thanks!

There are probably as many approaches to it as there are people that neck turn. Like the old Indian chief said in the movie 'The Mountain Men': "As many as stars in the sky, Bill Tyler".

And once you get past the basics of neck turning, much of the rest becomes personal preference based on what we as shooters 'think' works. Basic is a good thing.

So here's my 'basic' approach to what I 'think' gives me the best results:

I face off an extra shellholder .020-.025 then use this shellholder with a Body Die to push the shoulder back on the cases I'm going to neck turn. Now these cases have the shoulder .020-.025 further back than normal. Then I neck turn right up to the 'setback' neck/shoulder junction. When you fire the cases the first time, the shoulder blows foward, the end of the cut is now blended around the neck/shoulder junction and nicely into the shoulder, and the cases fit the chamber perfectly. Use a good amount of neck tension (.003-.005) for the first firing, set the seating depth up to jam the bullet firmly into the lands and use a fairly stiff load to make sure the shoulders 'pop' foward completely.

It works slick and only costs a couple of bucks for an extra shellholder. I scribe the side of the cut down shellholders with something really cryptic....like '-.025' or '.025 short' and keep 'em in my neck turning tool box in a plastic baggie. You don't need a lathe to cut 'em down, either. Before I got a little mini lathe, I did several on the side of my bench grinder wheel.

Just one approach to it. -Al

 

[Mirage416]

Al Nyhus,

That sounds like a good technique you describe.

Forgive me please, because I am just beginning precision reloading, and am still figuring all of this stuff out.

I ordered the Redding Competition micrometer neck sizer die the other day. It has not arrived yet. Can I bump the shoulder back properly like you describe using this die?

Also, what steps are important before neck turning, starting from new brass? Am I supposed to actually size the neck to fit the mandrel properly before turning? I was planning on ordering the K&M neck turner.

Thanks

 

[alinwa]

for the first firing, set the seating depth up to jam the bullet firmly into the lands and use a fairly stiff load to make sure the shoulders 'pop' foward completely.
-Al

Hate to keep floggin' this horse but shoulders don't "pop" forward, EVER without you false-shoulder them.

The case stretches at the rear.

checkidout

al

 

[Al Nyhus]

Hate to keep floggin' this horse but shoulders don't "pop" forward, EVER without you false-shoulder them.
The case stretches at the rear.
checkidout

al

alinwa: Respectfully....that's not the case (pun indended).

With firm neck tension and the bullet into the lands, the base of the case is firmly against the bolt face. You're overlooking the role of the extractor in keeping the case head in contact with the bolt face.

Stay warm, partner. -Al

 

[Al Nyhus]

Al Nyhus,
I ordered the Redding Competition micrometer neck sizer die the other day. It has not arrived yet. Can I bump the shoulder back properly like you describe using this die?
Also, what steps are important before neck turning, starting from new brass? Am I supposed to actually size the neck to fit the mandrel properly before turning? I was planning on ordering the K&M neck turner.
Thanks

I'm not sure if the die you ordered will do this or not...I'm not sure how much pressure the sliding sleeve will take. I'd advise using a cheap-o f.l. die or a Redding Body Die. It's a good idea to f.l. size new brass before neck turning. Make sure and get the correct expanding mandrel setup when you purchase the K&M tool. Ken at K&M is very helpful and will get you what you need the first time.

If you've not done much case forming and/or are unfamiliar or uncomfortable using the method I described just set the turner up normally and get your feet wet that way. Then you can move on to other methods and see which you like best.

Good shootin'. -Al

 

[alinwa]

alinwa: Respectfully....that's not the case (pun indended).

With firm neck tension and the bullet into the lands, the base of the case is firmly against the bolt face. You're overlooking the role of the extractor in keeping the case head in contact with the bolt face.

Stay warm, partner. -Al

Thanks Al

OK....... even MORE respactfully, ........You might wanna' try some tests before believing the old saw about seating long. I KNOW, I KNOW, It's Common Knowledge......

It's still wrong.


Back about '97-'98 me'n Skip Otto and Frank L Murphy (We Are Doubly Diminished ) got into this for real. And a bunch of otherbody's too. For my own testing I did everything I could think of to increase neck tension including making cases from over-length brass that ended up so thick that they had to be neck turned for a factory chamber. I Super Glued necks, JB Welded them and ran tensions so high that I had bullets splitting open on the ogive creases.

I even got some to stick!

BUT............

When I got the bullets to stick they STILL ran into the lands.

I bruised my palms.


They STILL ran into the lands.

I guess if you've got a fitted extractor with under a thou of clearance then you're undoubtedly right, that WOULD hold it......... but a bullet won't. None of the rifles we tried were this tight the extractors. I've yet to see an extractor which won't click over a case which is .003 short, beyond that some will start to fumble. But that's just what we found, maybe some are tighter than this.

I've probably still got 20-30 dead primers kicking around from those experiments. BTW, it's HARD to kill primers!!

The reason that this all came up back in the day was because The Skipper was a persnickety old fart and tended to measure/test stuff. Like barrel droop and bolt slap, and casehead squareness....... the thing started when Skip was looking for a better way to "square up caseheads.."

Avoid unsquare ones is a good answer

I AM warm Although this weekend it's supposed to freeze! And they're predicting "Lumpy Rain" clear down to the valley floor!!! LAWDY, it's gonna' shut the town down.......glad I can shoot from inside, I might turn the heat on.

al

 

[Al Nyhus]

'Mornin' alinwa.

At the risk of derailing this topic....let's take it a step further, okay?

In your estimation, how much excessive headspace ('cuz that's effectively what I'm creating when I shove the shoulders back) will cause case head thinning and the case head seperation that we're constantly warned of? In other words..how much 'shove back' is too much?

We can also start a new thread on this if you'd like.

Talk later....headed to work and then to see the dentist.

 

[alinwa]

'Mornin' alinwa.

At the risk of derailing this topic....let's take it a step further, okay?

In your estimation, how much excessive headspace ('cuz that's effectively what I'm creating when I shove the shoulders back) will cause case head thinning and the case head seperation that we're constantly warned of? In other words..how much 'shove back' is too much?

We can also start a new thread on this if you'd like.

Talk later....headed to work and then to see the dentist.

EVEnin' Al

To do it one ONE SHOT takes either very old and brittle brass coupled with .005-.006 hs, or even more clearance, so much head play that they'll barely fire. Otherwise it takes repeated firings. I've seen both cases but the one-shot situation is not common. The last one around here that blew the head off a FACTORY round was a decent Marlin bolt action rifle which the older gentleman fired with 40 yr old ammo. The ammunition cases had been fairly green when he wiped them off with polish......the box was rotted.....THAT sort of old......... Busted two cases right off. I checked the headspace right at .007....... New brass will stretch a LOOONG ways. Remember that big ol' case started out as a little brass button that just got hammered repeatedly until it was squished out to size and looked like a case.

The other problem exists from reloaders who "set their die to bottom out on the shellholder" because that's what the book said. EVERY TIME you set the shoulder back you're shoving brass out through the neck and EVERY TIME it "fixes" itself by slamming forward, locking there and then streetching the brass back to bottom out on the boltface. ((((The usual "fix" for this is to grease cases. Greasing cases works OK some of the time for short BR/PPC type cases but the cases never all fireform exactly the same because they're not all GREASED exactly the same. Folks who do this are forever culling cases which feel different or seat different. Furthermore, this is the actual reason for canted or out of square caseheads, THIS is what The Skipper was fighting. I suppose if you greased, wiped the chamber, greased, wiped etc you may avoid inconsistencies due to buildup but WHY???))))) Now, for the casual factory reloader this whole thing is an insoluble problem. The factory dies and factory chambers are always completely mismatched and the "solution" is over-sizing, accomplished by making resize dies which size clear back to factory spec. Without going into all of the problems generated, suffice it to say that this is also why all of the newer reloading manuals tell you to look for the grainy ring which indicates incipient head separation. Any rifle system which requires you to repeatedly trim brass to length HAS EXCESS HEADSPACE. Period. The dies are set too low, the fittages are wrong or the chamber is stretching. The newer Hornady manuals explain this really well with actual photos showing clearly the thinning brass at the caseweb/body junction. This junction is where ALL of the brass comes from. I did a quickie websearch for pix of incipient casehead separation pix and came up dry but I did find this Bellm site which in a quick scan seemed to have accurate information.

http://www.bellmtcs.com/store/index.php?cid=172


For FACTORY stuff you're just stuck with whatever your particular matchup will allow.......probably 3-5 reloads and then chuck 'em. For the factory guys reading this, IF YOU'RE TRIMMING OFF BRASS you're headed down a wrong road. Trim once, NO MORE THAN twice, and hurl the brass into the landfill most postehastily.







Now, back to the .002 or more setback for initial fireform..... Doing it once or twice ISN'T DANGEROUS but it results in inferior brass. (((I know, I know, "If my gun shot any better it'd be illegal!" ))) Really square brass WILL AGG BETTER. And cases will last literally forever with ZERO trimming and they will always shoot well if you so choose. I've got BR cases which have been fired so many times that the flashholes are eroded and they've never been re-trimmed to length. I'll often fire a set of cases more times during one load workup than many folks fire them in a barrel's life. My normal routine is to grab up five cases and shoot/load/shoot/load them 8-30 times. In one afternoon I'll run the same cases thru the dies/rifle until I'm done. Sometimes I'll keep those 5 cases for several barrels........maybe 50-80 firings on them. And I never worry about culling through match cases for fit, they ALL resize and seat and chamber alike. My latest 6X47 project I had to make up 160 cases for 600yd comp. I lost none except for stupid. I culled them for casewall runout and stuck them in my box. They're on their 4th go-round and you couldn't tell them apart for feel. Grab any one at random and it will (does) measure out with the others.

I set all of my chambers short.

I bump every shoulder to crushfit just for fireform.

I set my dies to headspace at .0000 (This often requires readjustment for temperature changes, true zero....I'm good at it.) Absolute zero is unnecessary, you can get by with a half a thou and rely on case compression for resizing, never sliding the shoulder. Sometimes even .001 but in this case I suggest you lube only the base of the cases, let the shoulder stay locked and compress the sidewalls of the case. Or, (I'm not ADVOCATING this ) if your die is hardened and you're real tool handy and measure handy and into saving steps....... set it up to use Butch's for your sizing lube. I save my clean wet patches and use them to wipe my necks clean, AND as resize lube! I've got cases that've been sized 30-40 times and the Butch's hasn't thinned or weakened the necks as far as I can tell. Of course I only do this when shooting/loading/shooting/loading in a controlled setting. In other circumstances I use clean patches (Ohhh the WASTE ) to wipe the necks and apply the Butch's. I also am a big believer in die wax....... THIN......


Soooo, in your case there's ZERO danger of separation. You're using less than factory clearance on new brass....... but try it my way and your holes will get even rounder


seriously......

These thirties are freakin' SCAREY!!! Fireforming for my 30X47 I actually had to call Jim Borden I was so excited. He made me a couple barrels for an HBR gun I'm building on a 700, an action he fixed up for a guy's hunting rifle. Rem action with the mag-box still in it. Dang thing will still function as a hunting rifle! I bought it with a beasty heavy McMillan A-2 stock on it. He made me barrels but the other parts aren't ready and I wanted to shoot it. I screwed this weinie liddle Hart barrel on and bolted everything together.....gun looked and felt like it was popping a wheelie. I crammed some pillows into a front rest and balanced that ungainly "Tactical" stock into place.....felt like I had to bungee it down to keep it from tipping over......


I grabbed me some BIB's and a load from my other HBR chambering (developed 14yrs ago on a .308 case minus .200) and layed all over the (boresighted) weapon and shot a hole. It was over 3" and up 7". Ok, so's I'm on paper.

I fired again, nuttin.

??

I fired again

NUTTIN!

!!

So I pulled over a half a hole and made a jelly bean.......


Hokey SMOKE Bullwinkle!!!!!



It's never let up....... I fired it 30 times to make 30 cases, but it's rightful stock is setting in the barrel vise with the sides sawed off and hunks of carbon fiber all fuzzing out.....


ACT'rally....... On this gun I had Kiff make my reamer to match my 14yr-old chamber and Neil Jones die....... I actually FIREFORM the cases with shottygun powder so's I can trim them up for real. The firings in the actual 30X47 were just to "pop the necks out" after neckturning

For FUN

This gun WITH AN A-2 STOCK is so fun I've let two other guys shoot it just to show off.

Kiff's a frickin genius die-maker measurer-upper........



al