Neck turning.

[Varmint Hunter]

Shooting mostly heavy varmint rifles; I was committed to neck turning for consistency and/or turning for tight neck chambers. However, I tend to watch what some of the national BR guys are doing, or not doing, and still winning. Now I only turn when needed to accommodate a minimum spec chamber or a tight neck chamber. My newest 6mmBR rifle has a no neck turn chamber for current Lapua brass and shoots quite well.

Some things we've just got to "un-learn". I've recently started to anneal cases and I haven't formed an opinion as to the usefulness of this process yet. I did, however, notice that some of the leading BR shooters are not annealing the cases that they use 10-15-20x.

 

[Mikecr]

Some things we've just got to "un-learn". I've recently started to anneal cases and I haven't formed an opinion as to the usefulness of this process yet.

That's wise.
Annealing is nothing new. It's just one of the many fads at the moment. These come & go in cycles, with the reason being that humans always head for extremes.. We always go too far, right through what worked, and past it.
Then someone (that folks would listen to) figures out that we're better off without it. End of one cycle, beginning of next,, then we'll stop all annealing and engage in efforts to diamond harden our necks..

 

[DustThroughaFan]

"Finished neck thickness after they cleaned up was .0105. Is that too thin or is it good to go"

Generally speaking - I prefer .003"-.004" of neck release on a hunting rifle. Your loaded round neck diameter will be .329" with the turned brass. It would be helpful to know what the chamber neck diameter is. If there is too much neck expansion upon bullet release, the necks will get work hardened as you reload or you could get premature neck cracking.

Saami chamber drawing, from my interpretation, says .3421"
So if my loaded diameter with the brass I turned being .329" that would give me .0131" clearance. Seems a little wide.

I only turned five of them. I'm going to start load development with them the way they are and see what happens.

Been a long hard fought battle with this gun and I'm down to trying to rule out every possibility. That's why I was going to try neck turning. Doesn't sound like it's needed though from input here and reading around on the forum. General consensus seems to be a toss up really.

 

[eshorebwhntr]

That's the end all be all...see if it works for your set up. If it doesn't, don't keep doing it. I agree that it's a touch on the thin side of what most do but doesn't mean you ruined it by any means. Try it and go from there

 

[dok7mm]

I just turned 150 pieces of Peterson 7mm Rem Mag brass for a friend. We measured to come up with a start of
.0135" turn. We fired a couple and we couldn't slide a bullet in the fired case, so turned them to .0132" and fired them again. With pressure we could push a bullet into the fired case. I set up for a turn of .0130" and the bullet slid in the fired neck easily. He fireformed 50 rounds today and was very happy. Every 5 shot target was under an inch with no load work up. He had little powder on neck, nothing on shoulder.

I'll use how I turned it to help you.

I started with my reamer print, we both use, the neck ID is .3145". Step 2 is subtracting .284, the bullet diameter. That leaves .0305". Then subtract the .004" clearance I want to use - that leaves .0265" . Lastly, divide by 2 for the 2 sides of the neck. That gives the neck thickness .0130". I measure each case at 4 points, they should be the exact thickness, if you are doing it right.

I turn necks on 9 hunting rifles and depending on caliber, neck ID or brass thickness, I always end up with .0300" to .0140" turn . I have turned over 5000 cases over many years, but I know what the chamber neck ID and brass (I already have in hand) + neck thickness to start.

I think the turn itself is generally to enable release the bullet cleanly, be it the chamber or the neck thickness.
I also believe the turn offers more concentric release into the lands, therefore giving some level of accuracy.

Is it necessary? No! Millons are shooting well with never turning. It's just a extra step towards fitting brass to your chamber.

 

[BrentM]

I used to turn necks on saami spec chambers too. I was only turning enough to clean up 90% of the necks and I might see 1 out of 100 cases be extreme. In most cases I could turn down to .0135-.014 and clean up the thickness enough creat concentric ammo.

Today, unless I spec a tight chamber, I don't turn. I use a mandrel. The results are very similar in concentricity and velocity variation as turned necks.

I know I'm not adding anything new to the discussion but I think you'll find more value elsewhere or switch to a mandrel expansion process. I'd rather have a thicker neck for sealing the chamber, lasting longer, annealing process etc personally.

 

[Philward]

First time turning necks so I know nothing about it. Turned me a mandrel in my lathe and sharpened up some hss then I turned a couple pieces of remington 300winmag. Finished neck thickness after they cleaned up was .0105

Is that too thin or is it good to go. There was about one and a half thou difference in most cases, some had two thou. Before turning. Turned, they were spot on.
View attachment 450464View attachment 450465

0.0105 seems too thin unless you have a bushing die that is small enough to compress the neck far enough to hold a bullet well. I turned some 7RM at 0,011, brass was thin already I think and I was just cleaning it up so it was even, and my standard die would not size the neck down very much. The loaded bullet was barely snug.

 

[nksmfamjp]

Well. As a number, 0.0105" is probably not too thin, but it is borderline. to me normal on a no nt chamber is about 0.0135". I've see nt chambers as tight as 0.008", but I think 0.012" is more common for nt chambers. Mind you these are generally tight neck chambers like at .262" neck in 6mm.

Cutting a 30 cal …..well, the brass is supposed to be 0.015" for a loaded round diameter of 0.338" in a factory chamber running 0.343"ish. When you have a 0.343" chamber or abouts, you don't want to cut thinner than about 0.0135, IMO. That is because firing and sizing can overwork the brass pretty quickly with it moving so much. Annealing helps, but…..you can see we are just going too far down the rabbit hole. If that doesn't clean them up 80% or so, toss those cases. They are just too bad….aka Winchester.

They should have started at 0.015"ish…..right? What diameter cleans them up 80% or so?

Honestly, buying Lapua, ADG or Peterson brass will be an easier "solution" and are not as expensive as we think!

 

[Varmint Hunter]

When I started neck turning for SAMMI chambers I only looked to get (about) a 50% clean-up on the neck. This allowed me to remove any high spots without changing the neck thickness to any degree. Today, I'd say that it probably resulted in an immeasurable improvement.

 

[Mikecr]

I just turned 150 pieces of Peterson 7mm Rem Mag brass for a friend. We measured to come up with a start of
.0135" turn. We fired a couple and we couldn't slide a bullet in the fired case, so turned them to .0132" and fired them again. With pressure we could push a bullet into the fired case. I set up for a turn of .0130" and the bullet slid in the fired neck easily.
I started with my reamer print, we both use, the neck ID is .3145".

Something isn't right there.
.3145 reamer (-) .311 1st turn loaded neck OD = .0035 first clearance.
.3145 reamer (-) .300 final turn loaded neck OD = .0045 final clearance.

You're saying bullets would not slip in the necks with 3.5thou clearance, but would with 4.5thou clearance.
But necks only spring back around ~1/2thou.
1/2thou from reamer would leave 3thou clearance for bullets to slide into with your first turn, and 4thou with final.
Should be no problem, with nowhere near interference.

I suspect that your chamber neck is not .3145,, but .3115
Check it, and check that worn out reamer.

 

[dok7mm]

Something isn't right there.
.3145 reamer (-) .311 1st turn loaded neck OD = .0035 first clearance.
.3145 reamer (-) .300 final turn loaded neck OD = .0045 final clearance.

You're saying bullets would not slip in the necks with 3.5thou clearance, but would with 4.5thou clearance.
But necks only spring back around ~1/2thou.
1/2thou from reamer would leave 3thou clearance for bullets to slide into with your first turn, and 4thou with final.
Should be no problem, with nowhere near interference.

I suspect that your chamber neck is not .3145,, but .3115
Check it, and check that worn out reamer.

I checked my reamer print today, it's .3140". I'm not going to argue with you on spring back as I was only trying to help the OP figure out his turn math using my 7 Mag.

Chamber neck .3140" minus bullet .284 = .0300" minus .0040" clearance = .0260"
divided by 2 equals .0130".

We all know there is miniscule variants in chamber neck prints, spring back and even in the turn. There is no .000000x involved in turning brass.

My last word: I don't give a rat's *** about how you feel about my reamer being "worn out". We are quite happy with it on its 3rd chambering.

 

[ButterBean]

When I started neck turning for SAMMI chambers I only looked to get (about) a 50% clean-up on the neck. This allowed me to remove any high spots without changing the neck thickness to any degree. Today, I'd say that it probably resulted in an immeasurable improvement.

^^^^^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^^^^^^^

 

[MagnumManiac]

First time turning necks so I know nothing about it. Turned me a mandrel in my lathe and sharpened up some hss then I turned a couple pieces of remington 300winmag. Finished neck thickness after they cleaned up was .0105

Is that too thin or is it good to go. There was about one and a half thou difference in most cases, some had two thou. Before turning. Turned, they were spot on.
View attachment 450464View attachment 450465

I never turn to less than .013", even with a sloppy chamber or a 'neck turn only' chamber. I used to turn to .012" in my comp 300WM, it was too thin and caused premature cracking.
Nowadays, I only turn to clean up the neck, I don't turn to a desired diameter anymore, no need, as long as the brass cleans up for about 80% of it's length, good to go, as I don't size the entire neck either.

Cheers.

 

[MagnumManiac]

There is also gas blow back between chamber and case preventing consistent sealing, and formation of a carbon ring where sealing finally occurs.

I've read where some BR shooters had turned necks all the way down to 8thou thickness. Pretty extreme, but I'm sure it's part of their plan. Their chamber must be set up for that.
The only advantage in potential there is LOW neck tension. Low tension = low variance of tension, and a high starting pressure can still be obtained through bullet jamming. I might do that if I shot a 6PPC.

Most of the time, I turn necks. But not where that action would leave excess clearance.
I consider anything over 2thou clearance as excessive already.
I've had guns with more clearance than that, but there is nothing I can do about it, and I definitely do not need to turn brass for it.

So what would it hurt if you don't turn necks? IMO, nothing.
If you have enough clearance, and you cull out cases departing in thickness and variance, and mandrel expand in a pre-seating operation, You can make straight ammo with consistent bullet release.
You'll gain nothing with turning.

With this scenario of having too much clearance, which I govern on my own reamers to be .003" clearance, I have played with brass brand to close the gap. My custom 25-06 was chambered with a SAAMI reamer spec and has .006" clearance with most brands of brass, but necking down Lapua 30-06 brass brings it down to the desired .003" clearance and a skim cut will bring it out to .004", which is good for me as that thing shoots to 3/8 MoA consistently and does go below 1/4 MoA with a certain bullet regularly.

Cheers.