Case Neck Turning, for a Tight Neck chamber

[Homer]

G'Day Fella's,

Earlier this year, I purchased a box of Lapua, .22-250 Rem, to try in my .22-250 AI chambered rifle.
This rifles is a switch barrel, Trued and Sleeved Rem 700, and the .22-250 AI barrel, has a tight neck chamber.
So before I can fire a shot, I first have to make the brass, compatible with the chamber.
I have a http://www.sinclairintl.com neck turning tool, and the appropriate neck expanding and neck turning mandrels, for this job.
I initially started doing this by hand............

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But as I was doing this, I remembered that I had a Case Holder (Simplex brand?), which I then modified, so I could use a cordless screw driver.
I first machined off the Hex head of the 5/16" bolt, and then made it and part of the bolt shank, into a 1/4" Hex drive, to fit the cordless screw drivers, Quick Change chuck.

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I also counter bored the inner face of the case holder, and machined up a Brass insert, to fit in there.

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This speeded up the job and it appears it was doing a better quality job, over doing it by hand.
But, Speed sometimes comes at a price......... at $1.78 retail price per case, it could also be expensive, if I pushed it to hard to soon......... BUGGER!

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I also debured the inside of the case neck and uniformed the Primer Pocket, while I was at it.

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Oh, and here's an image of the rifle, along with it's spare 6.5x47 Lapua barrel.

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Hope that helps.

D'oh!
Homer

[Stix]

[Apollo]

Not a bad effort although the reverse way I go about it which probably caused the stuffed case. How much are you cutting per pass and how are you measuring the case neck thickness. ?

Don't know if you would like some hints for a better job in the future.

Already been accused of giving someone a lecture here so I'm not going to offer advice unless it's wanted...

[Homer]

G'Day Fella's,

Thanks for your complements and your advice and offer Apollo.
Any additional advice (from yourself, and other knowledgeble people), would be very much appreciated.

I no longer bother, with doing a roughing and finishing cut on the case necks.

Avagreatweekendeh!
Homer

[brett1868]

Is it usual to cut down into the shoulder like this? I'm assuming its because they'll be fireformed into the AI variant.

[Homer]

G'Day Fella's,

Yes Brett1868, well at least that was what the Gunsmith (PSECO) that built it, told me to do with this barrel.
It may have a bit to do with controlling the dreaded Donut?

D'oh!
Homer

[Apollo]

Hi Homer, well. This is advice not a lecture. Everyone does things their way and not a lot of people have a lot of spare time on their hands like I do in forced retirement but I always think that if a job is worth doing then it should be done to the best of one's capability. Just my opinion.

I have probably neck turned a couple of thousand or more cases for myself, mates and others. These are all done to the standard required for precision competition target shooting even though they may be only used for general varminting rifles, including my own. It's just getting that little edge that may or may not improve accuracy.

My mentor many years ago when I first wanted to try neck turning was Stuart Elliott (BRT) who supplied an enormous amount on advice and photos. I think I have it pretty much down pat these days.

So, this is advice and observations.

I have never tried to turn a neck by just hand. I don't think it can do the job properly. By looking at your first photo it looks to me that the shaving coming off is too thick and then the second photo to me shows too uneven a cut like it's skipped some material. You say you aren't bothered doing a rougher cut then a finish but in my view this is required if you are taking a lot of material off. Also required if one wants the neck thickness to be as even as possible. Some of my cases like my 6.5x47L and 6mm PPC where the necks are required to be really thin (0.010" & 0.085") I do in 3 cuts with the last very fine.

In my view, I think holding the Neck Turner in a vice is not the best method. I use a K&M Power Adapter in a Cordless Drill on part low speed (less than 100 rpm) for my first cut. I hold my K&M Neck Turner in my other hand so I can just guide it onto then down the neck with virtually no pressure just letting it cut it's own lead then with a slight pressure at it touches the shoulder of the case. Then back it out slowly. I then do a second run down to the shoulder and back slowly. I have another Neck Turner setup for the second cut and do the same. If I'm only making the two cuts then the last pass I do at higher speed, say 3-500 rpm which seems to give a nice even final cut if anything at all other than a polish. Finally I run a kitchen scourer over the neck at highest possible speed for a polish, some use steel wool but I don't like the possible mess it leaves. BTW, I think I have a half dozen neck turners all set differently.

The neck that you show in a photo that has been torn off I would believe is the result of being too aggressive and lack of feel with the turner being in your vice rather than in your hand.

I use both a Mitutoyo Ball Micrometer (for neck thickness) then highly accurate normal Micrometer to make my final measurement of the case neck with a bullet seated in it making sure I measure the area of the bullet's pressure ring to ensure I have the clearance I require in a tight neck chamber. I do not use Calipres for any of these measurements as it's just not accurate enough of a measurement.

As I said, each to their own. I hope I have explained my method I use to get the best result from the time I spend. I know my efforts are rewarded from a few people I have done this for that win 1st places in national competition.

Sorry if I have gone overboard a bit much.

[Apollo]

G'Day Fella's,

Yes Brett1868, well at least that was what the Gunsmith (PSECO) that built it, told me to do with this barrel.
It may have a bit to do with controlling the dreaded Donut?

D'oh!
Homer

John Giles (PSECO) is a pretty smart cookie and one of the best in the business.

The amount of cut down onto the case shoulder is something I would have judged by doing one with a fairly deep cut cause the shoulder is going to push forward some of it material when fireforming but I would do one case, then fire it to see what the result was if it needed more or less cut.

Creating a Donut is not a big issue really as long as the bullet pressure ring/base is not in that area. If it's well forward of the neck/shoulder junction it's no problem and can be fixed later down the track easily.

[brett1868]

G'Day Fella's,

Yes Brett1868, well at least that was what the Gunsmith (PSECO) that built it, told me to do with this barrel.
It may have a bit to do with controlling the dreaded Donut?

D'oh!
Homer

The dreaded donut is on the inside of the case and generally I remove it by the use of a cutting pilot when neck turning. I cut to a couple thou short of the shoulder and use a cutting pilot. With your setup I think that a cut that far down the shoulder if using a cutting pilot might leave the brass a bit thin. If your not using a cutting pilot then I'd think the donut should fire form out though I prefer to cut rather then rely on other means of removal. Like you, I use an electric drill but take multiple shallow cuts using sizing wax as a lube on the mandrel. Neck wall thickness is measured using a Mitutoyo Wall Thickness Micrometre I purchased from BRT. I'll be keen to see the results of your work once you get shooting

[Apollo]

Brett, I beg to differ.

The dreaded donut can be avoided if you cut the outside of the case correctly down onto the shoulder. I have "cutting pilots" as you mention and really I have never needed to use one. In fact I put them all away as you really need to be careful using one that it doesn't dig into or scratch the inside of the case neck when feeding it in.

It's also very calibre specific of which will create donut's as most don't over numerous firings. Case design.

[SCJ429]

Would you end up with a donut when forming a 22/250 AI? I would have thought you needed to use the thicker shoulder to end up having problems with a donut. Say when forming a 30 BR from 6mm BR.

Nice rifle, do you use the Hopper Stopper in any competitions?

[Apollo]

Sorry to butt in off topic but I have done a few hundred 6mm to 30 BR and I have done a first firing to find a donut straight up so it's then a run through the 30 cal mandrel and second neck turn to remove the donut on the outside, no further donut. The first neck turn was a big cut into the neck, just par for that wild cat case forming. My K&M Turner may not cut far enough up the case neck at the correct angle.

Now that you mention 30BR, it's the only calibre I have that I've seen a donut which I knew was going to happen.

Love the 30BR, what a magic calibre. Deadly accurate, no barrel or case wear... Have two rifles chambered in 30 BR. Boy are they accurate.

[Homer]

G'Day Fella's,

Thank You to you all, for your experience and advice on this process, very much appreciated.

FYI, here is probably the best 5 shot group I have ever shot (with this same .22-250 AI rifle (oh and that should read BM-2 Powder, and Remington cases), and I aint no BR shooter.

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Avagreatweekendeh!
Homer

[SCJ429]

Nice shooting, especially with a hunting bullet. What sort of speed do you get out of it?

I load for a straight 22/250 and it liked 2208, still pretty handy the old 22/250.

[SCJ429]

I too am a 30 BR fan, surprising the speed you can get out of that little case. I have had a 7mm BR for a long time in a hunting rifle, quite a little thumper.

[Homer]

Just over 3800fps (Oehler 35P), with this load SCJ429.
It will go faster but I'll take this kinda accuracy, over additional speed, any day.

D'oh!
Homer

[marksman]

the idea of cutting longer than the neck into the shoulder of the case to stop do-nut forming is because when you fire the case the cut will disappear on the outside and be thinner on the inside, one way of getting rid of or stopping do-nuts
I use a pedestal drill on low speed to neck turn using K&M tools with a carbide cutter that reams the inside of the neck and stops the do-nut forming
using power to do this job does make a better finish as you dont get the cut lines like you do when turning by hand
when making dasher or 17 ackley hornet cases I neck turn before forming the cases and turn way further down the neck so the shoulder is the same thickness as the neck so no do-nut is formed
and as far as having a fitted neck, its one thing that can be done for squeezing that last ounce of accuracy and the great thing is it cost you nothing but time prepping your brass
as usual Homer nice work

[Homer]

G'Day Fella's,
Markman, Thank You for your kind words, all of that info, and the pedestal drill tip mate.

I have a 200 6.5 x 47 Lap cases and 100+ .338 Lap Mag case, the I want to even up the neck thickness on.
I'll get to this, some time over summer, and if I remember to, I'll take a few images, and post on here.
Both these rifles have minimum spec chamber neck diameters (but not Tight Neck).
I have been advised that evening the case neck thickness, might improve group consistancy a little.

D'oh!
Homer

[Homer]

G'Day Fella's,

I finally got the 6.5x47 Lap cases/necks finished
As I suggested, this barrel has a minimum spec neck diameter chamber but not a tight neck one.
So, all I'm trying to achieve here, is to uniform the case neck thickness, nothing more.
The initial neck turn, shows a similar pattern with all the cases necks.
That being, the case mouth area, being a bit thinner than the lower section?

Here's some images;

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I'll give these a rip down range, and see what occurs.

Onto the .338 Lap Mag next............

D'oh!
Homer