neck truning of cases

If I had to turn my brass 3 or 4 times, I would buy a different tool...........
Later
Dave

And there you have it. ;)

When expanding 6BR brass up to .30 or down to .22, (or the 6.5X47 up to .30) I cut the inside of the necks perfectly round before turning the outside. The 220R Lapua necked to 6 didn't seem to benefit from this.

Perfect inside necks definitely made a difference in A-B-A testing. -Al
 
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And there you have it. ;)

When expanding 6BR brass up to .30 or down to .22, (or the 6.5X47 up to .30) I cut the inside of the necks perfectly round before turning the outside. The 220R Lapua necked to 6 didn't seem to benefit from this.

Perfect inside necks definitely made a difference in A-B-A testing. -Al

What tool are you using to cut the inside?
 
What tool are you using to cut the inside?

Basically chucking reamers in .0005 (half thou.) increments that pilot on a hardened steel flanged bushing. The case itself is held in a Wilson case holder. It's critical that the case neck (after expanding) be parallel with the long axis of the case body before doing the inside neck reaming. To straighten the neck relative to the case body, the unturned neck is sized using a die whose neck dimension is .001 under what the neck o.d. measures after expanding.

Cutting or reaming the inside of a neck after it's been outside neck turned is an accuracy killer.
 
Thank You Big Al!!!!

that is freakin' pure GOLD right there......taking the skin off the inside just makes the brass so much more-better tractable

And folks wonder why I'm all he'te' about protecting my necks :) it's cuz they're WORK to make right but ohhhhh when they're right.......it's like good sox.
 
Basically chucking reamers in .0005 (half thou.) increments that pilot on a hardened steel flanged bushing. The case itself is held in a Wilson case holder. It's critical that the case neck (after expanding) be parallel with the long axis of the case body before doing the inside neck reaming. To straighten the neck relative to the case body, the unturned neck is sized using a die whose neck dimension is .001 under what the neck o.d. measures after expanding.

Cutting or reaming the inside of a neck after it's been outside neck turned is an accuracy killer.

thanks for the info....much appreciated....
 
neck turning of cases

what ever get you to your goal .
I think Wilbur is right'
The object is to get to your desired wall thickness.
I listed a bunch of steps. {Just the way I do it}
It gives me good success and No case losses.
I take it easy and put the time in.
 
Lathe Tailstock Die Holders

G'day from down under.

I usually neck turn my case necks with a Lyman neck turner, but as I have a 7x14 mini-lathe it could be more practical to utilise this.

What I am trying to work out is how to hold the cases securely from the tailstock end.

Local (Oz) dealer cannot obtain a Lyman case holder as a spare part so are there any alternatives?

* Doghunter *
 
The way I do it on a lathe is simple, I first turn a mandrel from a grade 8 bolt to the exact dia. of the bullet taper the front a little . Then push the case on with the tailstock turn to desired dia. 1 pass let the carriage there! Pull the case off push another on. Very simple. I run a dial mike and have never seen runout! Also I have taken cases that were turned by hand and have seen lots of runout. An old 1000yd shooter named Howard Wolfe showed me this method 45 years ago! I made a jig to pull the cases off. If interested let me know!
 
Just to add a bit re: necking the 6BR to .30....

Manually expanding the necks results in a 'funnel shaped' inside neck along it's length. In other words, the neck i.d. will be smaller at the new neck/shoulder junction than at the mouth. This taper doesn't just start at the new neck/shoulder junction (a traditional 'donut'), but begins about half way down the neck. People assume that because there's a 'lump' at the bottom of the new outside neck/shoulder junction (after expanding) that all the material has been moved to the outside. Not so. A simple pin gauge dropped in the neck will confirm this...normally on the order of .003 total taper, but I've seen as much as .005 with some Lapua 6BR cases.

Expanding the necks on a lathe works really well. With the lathe around 500 rpm, expanding the necks over an indicated, tapered expander keeps the necks straight with the body and makes the neck i.d. nice and round. The inside of the necks also have a nice burnished finish when done this way. 50/50 STP and Mobil 1 mix is a good lube for this.

That said, I still prefer doing it manually. You'd be amazed how nice it is to turn necks on cases whose inside necks are perfect.

Honestly, these 30BR's and 30X47's (6.5X47 parent case) shoot so well that you can get by with some pretty herky case neck prep. But there's more on the table for those willing to wade a bit further upstream.....;)
 
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The way I do it on a lathe is simple, I first turn a mandrel from a grade 8 bolt to the exact dia. of the bullet taper the front a little . Then push the case on with the tailstock turn to desired dia. 1 pass let the carriage there! Pull the case off push another on. Very simple. I run a dial mike and have never seen runout! Also I have taken cases that were turned by hand and have seen lots of runout. An old 1000yd shooter named Howard Wolfe showed me this method 45 years ago! I made a jig to pull the cases off. If interested let me know!


Like this:

Also, when making a 6PPC from a 220 Russian, or a 30 BR from a 6Br, they come out much nicer if you blow them out in a proper chamber before you turn the necks.

But as was said, there are multitudes of ways to arrive at concentric necks of the correct wall thickness.

https://www.youtube.com/watch?v=xykoVHY_Lkc
 
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I've blown out the 6BR cases to 30 using an old barrel, also. Cheapy 6mm bullet over H4198 works good. The necks end up quite a bit longer than the 'normal' neck up method doing it like this. Jackie's 30BR reamer reflects this neck length dimension.

Another way to skin said kitty.....:cool:
 
This has worked very well for me.

Runout is checked for every case neck.......to KNOW that set-up is turning to within 0.0001" T.I.R.

Many thanks to "Innocent" Francis, for his help years ago.

Kevin
119vz3b.jpg
 
"One-Shot" neck turning

No need to turn in multiple steps if one has the proper turning tool and properly matched expander.

I can reduce neck wall thickness over 0.005” in one turning and get 0.0001” or less TIR for a batch of fifty cases in a little over a half-hour.

I wouldn't bother buying any other neck turning equipment other than the Neilson “Pumpkin”. The ease of adjustment, and the ability to make very fine repeatable adjustments rapidly, makes it the best tool available in my opinion. It's also a round tool and the cutter and mandrel are recessed which makes it safe to use (this is important because of the way I use the tool). The tool is also massive enough to sink a lot of the heat from the mandrel. This helps control size consistency. Spend the extra money and get a carbide neck turning mandrel. Make sure you get the appropriate expander mandrel which is exactly 0.001” larger than the neck turner mandrel. This expander to turner mandrel tolerance is for Lapua 220 R, 222, 223, 6mm BR, 6.5x55, 6.5x47, and 308 Lapua brass. It may work for other types and brands but I'm not certain since I've never turned anything else. Cartridge brass from the different manufacturers varies in hardness and resiliency.

My method is similar to Mike Bryant's, except I don't bother holding or driving the case with any sophisticated holder – just by hand with a Sinclair “tap wrench” holder. I do it this way because it's faster. Think economy of motion. I try to make this job as fast as possible because I absolutely fu@#$%& hate turning brass!

https://youtu.be/CgtZ8QYOZW8

First I sort the brass by length and separate it into batches. I try to obtain a large enough batch of equal lengths so the cutter will remove metal from the shoulder equally from case to case. I don't trim because it saves an additional step. I absolutely fu@#$%& hate trimming brass!

Next I resize the cases in a FL resizing die. For the 6mm PPC, I start with 220 R and FL resize in a 220 R die. I push the shoulder back 0.014” by using a shell holder that's been shortened 0.014”. This will eliminate the “dreaded doughnut” - and after expanding and turning will give me a medium crush fit for headspace in my chambers. This shoulder setback step is only for the 220 R brass to PPC - since the PPC shoulder angle is more acute. The part of the shoulder set parallel to the cutter by this step allows for a concentric thinned section that becomes part of the neck/shoulder junction after fireforming, which nicely blends into the shoulder. Incidentally, I believe this thinned neck/shoulder junction allows for easier extraction with hot loads.

I chuck the “Pumpkin” neck turner in a 5c emergency collet in a benchtop lathe. I run the lathe at 700 RPM.

I Put a few drops of oil (Shooters Choice "FP-10" works well) on the neck turning mandrel. There is no need to have everything soaking wet with oil.

I cinch the case in the case holder and slowly advance the neck onto the mandrel. It will essentially “self-feed” with only a light amount of forward pressure. After the neck bottoms on the shoulder of the mandrel, I slowly back it off of the mandrel at about the same speed I use to advance it onto the holder.

I can usually cinch up a case and turn it...then cinch up another and be ready to go in less than forty seconds. The lathe isn't shut off for the session, which saves time. I absolutely fu@#$%& hate standing at the lathe turning brass!

I can easily get concentric necks within 0.0001”, and the batch will be on size within 0.0001”.

Another detail - usually my first three case neck walls will be 0.0002” to 0.0003” thicker than the rest of the batch. I can eliminate this by heating up the “Pumpkin” turning tool with a heat gun where it's warm to the touch – thereby starting with a tool that will be at a consistent temperature throughout the turning process.

There is no need for a fancy expensive lathe to do this job. If one is crafty and mechanically inclined, one could obtain an AC motor with a speed control or gear reduction and make an adaptor to hold a simple import three-jaw chuck. I use a higher-end lathe because it's quiet – I absolutely fu@#$%& hate noise!

Greg Walley
Kelbly's Inc.
 
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How much are you taking off?

Between friction on the mandrel and heat from cutting the brass warms up and expands.

A second pass at the exact same setting will often skim off a very thin layer.
 
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