If I force it the cartridge becomes stuck and when I eventully remove it by hammering on the bolt handle I find fine vertical score marks up near the case shoulder on one side.

Am I doing something wrong here? Or maybe the chamber is not square with the bolt or is a peculiar shape? Any ideas?

If they were, were they fired with very high pressure loads?

Have you checked the overall length to see if they need to be trimmed?

Do the cases stick before they are loaded or only after the bullet is seated?

quote:

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Originally posted by Stonecreek:
Were the cases originally fired in the same chamber?

Yes

If they were, were they fired with very high pressure loads?

No - low/ med pressure

Have you checked the overall length to see if they need to be trimmed?

Yes checked but no trimming required

Do the cases stick before they are loaded or only after the bullet is seated?

I did not try without a seated bullet, but I am confident that the bullets are 0.050 back. Checked on the ogive with a Stoney Point tool at the weeekend.

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[This message has been edited by Deerdogs (edited 08-07-2001).]

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Happiness is a 200 yard bughole.

It may be caused by the drag of the expander ball on the case neck when resizing.

Two things to check: case neck thickness - are the case necks of uniform thickness all the way around? If not you will need to turn the necks to make them concentric or inside ream the case necks then resize (or just discard that brass).

The other thing to check is the expander ball in the resizing die. Does it look round, or is it out-of-round?

If the expander ball and case necks are okay, use powdered mica when resizing. Dip the case neck into the mica and resize; the mica reduces the friction which may be stretching the necks.

George

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Shoot straight, shoot often, but by all means, use enough gun!

Check to see if the fired cases are eccentric. If the chamber is eccentric you can get the behavior you describe.

Otherwise a bulged case as described by Powderman seems the next most logical explanation.

Don

[This message has been edited by Don G (edited 08-08-2001).]

Since the body isn't being sized in any manner by the neck die and you are using brass fired in that chamber, my guess is that the chamber is eccentric. This is not at all uncommon.

Also, GeorgeS hit on a common problem in the expander pulling the shoulder out slightly upon its passing through the neck.

To isolate the problem here's what I'd do. Remove the expander from your die. Take a fired case and run it through the neck sizer and run it into the chamber to see if there is any drag or difficulty in chamber.

If there is no problem, then it's likely the expander is pulling the shoulder out slightly eliminating headspace and making chambering difficult. Then there are several solutions, the best and easiest is to lube the inside of the case mouth. There is another solution in polishing down the expander to reduce interference and drag at the expanding operation, but hold off on that.

If after neck sizing without expander, and chambering, there IS difficulty, then it's likely an eccentric chamber. The solution to that would be to partially full size with a full length die to reduce the shoulder and body area where the case might be blowing out a bit and causing the interference. You can determine where this interference is located by indexing the case, using a marking pen or diemakers solution to color the case, and running it into the chamber to determine where the drag marks are located in the chamber.

After neck sizing the one case you use for these checks, measure the neck with a micrometer. Then seat a bullet and measure the neck again. The difference is the "grip" on the bullet. If the difference is any more that .002" you might have thick necks on that lot of brass. The solution is to either turn the necks down a bit or polish down the expander to reduce the drag when you size.

If the chamber is eccentric you may wish to continue full sizing and eliminate the use of the neck die. Hope this helps.

quote:

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Originally posted by Deerdogs:
After neck sizing I find that I cannot chamber the cartridge.

If I force it the cartridge becomes stuck and when I eventully remove it by hammering on the bolt handle I find fine vertical score marks up near the case shoulder on one side.

Any ideas?

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I think it has been said above, but let me say it again:

If a neck sizeing die comes down to and presses on the shoulder, the body of the case will buldge out, maybe.

So: as you try your experiments to find which step causes the sticking case, also try an example with the neck sizer not quite down to the shoulder.

JerryO

I have found that expander balls are one of the biggest culprits in causing run-out problems and headspace problems. Lubing the case mouth with mica or graphite can help, but results can be inconsistant. I pull all of my expander balls out and size without them. I then call K&M and have them make me a custom expandiron mandrel .001 under bullet size. This makes sizing a two step procedure but I have been most pleased with the results of this method.

Hope this helps,

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RC

Adjusting Neck And Full Size Dies:

a. Lube a fired-once case, and then dip the mouth in powered graphite. Back the die off and run the case into it. Drop the press� ram, and look at the case neck-you should be able to see a line where the neck has entered the sizing portion of the die. Adjust the die down in small increments, and keep on watching the line on the neck of the case each time it is run into the die. When the line just reaches the point where the neck and shoulder meet, adjust the die down one sixteenth of a turn.

b. To lock the die in place, take a small mechanic�s socket and place it between the shell holder and the bottom of the die, and then press the ram and socket against the bottom of the die. Keep the pressure applied, and lock the die in place with the lock ring. This procedure squares the die with the shell holder.

c. To align the expander/decaper assembly, back off the lock ring and run a case up in the die and until it punches out the primer. Now raise the handle until the expander pulls into the neck of the case, and hold it there. With the expander in the neck of the case, tighten the lock ring. This procedure aligns the expander with the neck under tension, minimizing the possibility of pulling the neck out of line on the down stroke of the ram.

The shoulder creeps forward on firing to the stage where it is exactly the same dimension as the chamber. As a result chambering is difficult. I suspect LAPUA and Norma brass is soft enought for this to happen immediately on every firing. Even if you can chamber you run the risk of the bolt locking on firing not because of pressure but because the brass has expanded to the chamber and not shrunk back (having started that much closer)If you have a very slightly eccentric chamber (as many factory rifles do) the results of neck sizing might actualy be worse than full length sizing. This is because unless you index the case you will put it back in worse alignment than a full length case.

This has all happened in my 6.5 I've taken the lead from Callum at PRS who full length sizes all his ammunition and still guarentees accuracy to .4MOA

If you want to go half way house you can measure a fired case or 2 with the stoney point headspace comparator and set up your full length die until you set the shoulder back an amount that lets you chamber and extract OK. I do this because it seals more effectively on low power 100gr loads which allows me to run the 100s to the same POA as 120s I've not noted any accuracy difference. In fact the best group I shot was with full length resized Norma.

Always, always chamber several samples of sized brass, no matter what die you're using, to make sure your cases chamber freely. Otherwise, you'll be guessing where the problem is (like now).

Yes, the expander ball can pull the case shoulder forward just a bit, but this would happpen with the FL die also. Inside of necks should be lubed to prevent this, but I don't think it's your problem.

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Larry

I think I have isolated the problem. I put a magic marker index point on some fired brass then ran the brass through the chamber rotating it 45 degrees each time. Guess what. The brass would only chamber when offered up with the index mark in the same position. I guess this is what is known as a eccentric chamber. Is there any thing I can do about this? The rifle shots sub MOA so I guess I should not be too worried. But I would have liked to be able to neck size.

Full length size, but do it just so you barely set the shoulder back.

You can do this with an air gap between a standard shell holder and the FL die, but this gives you a variable setback as the sizing force varies.

Best is to use a set of Redding competition shell holders (about $35USD). These are shell holders with a thicker "deck" on them (+.002,+.004, +.006, +.008, +.010) so that the headspace length of the sized rounds is a controlled distance above SAAMI. This gives minimum working of brass with reliable results. You can "square the die" as normal practice when using them.

If, for example, the +.004 holder sets the shoulder back .001 from fired, you could "neck size plus" by using the +.010 three firings to work the brass less, followed by the the .004 on the fourth firing to set the shoulder back.

Hope this makes sense, it is easy and gives controlled results. Eccentric chambers are not uncommon at all, unfortunately. My custom M1A is very eccentric.

I've been told I'm not rich enough to be eccentric, I'm just crazy!

Don