I just got my rifle back from Hart with a 280 Ackley barrel and the stamp also says ".313 NECK".

The bullets are .284" and the Nosler brass mic's .013" to .014" neck thickness. So .284" plus both sides of the neck at .014" will be .312".

Is this too tight? I can outside neck turn with my Forster outside neck turner. What thickness would it be best to turn to?

I'd want at least .002 difference between the loaded round and the chamber.
In your case, I'd look at turning the necks to a max wall thickness of .013.

Tailgunner is right, you want at least .002" clearance between loaded round neck diameter and inside chamber neck diameter. And even that is not a whole bunch for hunting rifle. You certainly don't want to get your rounds dirty and try to chamber them. .002" is more suited to a BR or competition type rifle, where conditions and ammo can be controlled.

Btw, measure your loaded rounds, as opposed to your neck wall thickness, it is the better and more reproducable method.

Should you decide you need to turn necks for use in your new chamber, and should you decide this is not practical for a hunting rifle, it is a comparatively simple operation to run a neck reamer through your chamber, and have a neck diameter suited for factory (unturned) brass.

- mike

woods

didn't trust me?

woods

You definitely have a "tight neck" chamber most commonly found on Benchrest rifles.

As mho said, you need to measure neck diameter of a loaded round before deciding how best to turn case necks. Different brands of brass will give you different results so you need to decide what brass you intend to use. My own 280 Ackley is a Benchrest rifle and the custom chamber has a neck diameter of .312". I use Remington brass exclusively and turn my necks for a loaded diameter of .310". But I am an experienced Benchrest shooter. If you are not accustomed to working with "match" chambers you may want to give yourself a little more clearance.

If I were you I would ask Hart for a copy of the chamber print. You may find that the entire chamber is tight and some brands of brass may not be appropriate. For example, Norma brass is much bigger in the base than, say, Remington and will not fit a tight base chamber cut for the Remington brass. I don't use Nosler brass so cannot say how it would compare.

Additionally, a tight chamber may require loading dies made especially for the dimensions.

When you bought the rifle were you aware of what you were getting?? Tight necks and/or match chambers are not for the casual re-loader.

JMHO

Ray

MHO is correct, it is easy (and better) to get the neck of the chamber opened to whatever diameter you want for adequate clearance of your loaded rounds.

I prefer myself to outside-turn the case necks, but that is only because as an experienced benchrester it makes me feel warm and squigly to know that those necks are then of uniform thickness. That probably adds little or anything useful for a hunting rifle (except maybe confidence), but it surely doesn't hurt.

There IS, however, an older method which was quite popular among handloaders before the use of outside neck turners became so common. That is INSIDE neck reaming. L.E. Wilson and others still make and sell inside neck reamers of any diameter you want.

It is much faster and easier than outside neck turning. Just pick up the case in one hand and the reamer in the other and turn the reamer by hand into the neck.

The problems with inside neck reaming are:

1. You have to know what size reamer you want to use. Easiest way is to order a reamer .002" or.003" smaller diameter than your bullets (depending on how much neck tension you want).

Then size the cases, THEN ream them.

2. As the reamer will follow the hole, it will NOT "uniform" the neck thickness unless the reamer is used in combination with a reamer die. With a reamer die, such as are provided on request by RCBS and others, the neck is slightly sized WHILE the reamer is passed down through the top of the die to do its cutting. As the reamer shank is guided by the die, a properly made die will make the reamer follow dead enter of the die, rather than just follow the hole in the neck of the case.

Not suggesting you use inside reaming, though I do on a lot of my older hunting rounds. Just pointing out that it is another option.

A guy with a lathe can easily turn down a chucking reamer shank, and open an old sizer die neck to make his own reamer die set-up, if any of you think that might be interesting to do.

quote:

Originally posted by woods:
I just got my rifle back from Hart with a 280 Ackley barrel and the stamp also says ".313 NECK"...

Hey Woods, Really nice to see a Shop specify that info directly on the barrel.

Did you request a Tight Neck?

How does it shoot?

Hey HC

No, I did not specify anything except the barrel length, caliber and twist. Hart did that on their own without asking.

According to Bounty Hunter his 280 Rem has a fired outside diameter of .316" and a loaded OD of .310". So I'm not really concerned.

I will load one up shortly and check OD of a load on one case before I load more than that. I will also check to see how it chambers. I have already checked all the empty cases and they chamber easily. I will let you know the OD of the loaded round.

It has not been shot yet. Just got it and put the scope on.

Woods,
Even if it is marked you should measure it for your own knowledge and safety.

[QUOTE by Woods]I have already checked all the empty cases and they chamber easily.[/QUOTE]

Woods

I hope I didn't read what I thought I did. A new 280 Remington case should not chamber easily in a 280 Ackley chamber. There should be about .004" short headspace and the new brass should chamber with a crush fit to ensure fire-forming without weakening the case.

Ray

As Ray pointed out, the cases should chamber with a little resistance(crush fit for any Ackley chamber). You really need to measure the loaded rounds before you go pulling the trigger on this new rifle. Bounty Hunters rifle obviously has at least a .316nk and your's has a .313, so nothing about his chamber applies to your's. Sounds to me like you will need to neck turn your cases.

Hey Cheech

I am using Nosler 280AI new cases.

Nosler 280AI brass

Did not know that about 280 Rem cases being a crush fit in a 280AI chamber though.

A loaded round has the OD of .310". I would prefer to go ahead and shoot the first 25 and outside neck turn after. I am loading low to medium loads and will be breaking in the barrel at the same time.

Woods

I think all of us were assuming that you were going to fire-form brass from new 280 Remington cases. I know I did.

It sounds like Hart chambered the barrel specifically for the Nosler brass with .003" neck clearance. That should work great and you may want to reconsider neck turning since it probably won't be necessary.

All is well. Good luck with your new barrel. I think you'll like the 280 Ackley. It is one of the better cartridges around and probably the best of the 7mms.

Ray

I didn't even know anyone was making 280AI brass

quote:

Originally posted by pointblank:
I didn't even know anyone was making 280AI brass

If memory serves, it is a development from 2006, so it has not been on the market very long.

- mike

Okay

Finally got a clear day and got to the range. The gun shot very well.

Just started to deprime the cases and measured the neck. It mic'ed .311" close to the shoulder and .310" and the end of the neck. Took a bullet and it can be inserted by hand into the neck but with a lot of force. Tight without sizing.

The concentricity gauge showed the exterior of the neck is perfectly concentric, so the chamber neck is perfect, just very tight.

My question is, how much should I turn the necks down to now?

That's a perfect fit in my book. They don't need to be turned at all.

quote:

Originally posted by woods:
Just started to deprime the cases and measured the neck. It mic'ed .311" close to the shoulder and .310" and the end of the neck. Took a bullet and it can be inserted by hand into the neck but with a lot of force. Tight without sizing.
...
My question is, how much should I turn the necks down to now?

Woods, I went back to find your outside neck diameter of a loaded round, you listed that as .310". The way I interpret your last post, is that you have measured neck diameter of brass fired in your new chamber, and have come up with .310-.311" - correct? You can figure about .0005-.001" brass springback, which would give you a chamber inside diameter of .311-.312. This sounds as if it gels with the fact, that bullets only seat pretty hard in your fired cases.

For my taste, that is a tad tight for a hunting chamber. Although you might get away with it pressure wise, you might run into some grief in the field - you don't have a lot of clearance to deal with dirty, frosted or wet ammo...

If it was my chamber, I'd try to just skim turn the brass - i.e. reduce it with .001-.002". This turn is really more about taking off the high spots of the brass, as opposed to really achieving a neck wall reduction. Luckily, this is the easiest turn, and only requires you to have one neck turner set up - look hard at the K&M. I'd try turning, see how the rifle shoots (likely very well), and see how your clearances are after turning. If neck turning ends up being too much hassle, I'd consider having the neck opened.

- mike

Sounds like a possible hammer to me?