A bulge at the neck/shoulder junction developed in my once fired Norma cases for my 338-06. I saw this bulge, or ring if that is a better term, after firing several shots with no ill effects. These are Norma 30-06 cases that were expanded to .338, then loaded and fired and are now on their second firing. I necked sized the brass using a Lee collet neck die, and seated some Hornady 200 gr SP bullets. This bulge/ring measures .3700 to .3725 and extends up the neck approx .136. The neck of the loaded round measures .3630 to .3635. The cartridges chambered OK but I'm leary about shooting them. Has anyone experienced this problem and can you explain it? Any help, comments, or opinions will be welcomed.

The smaller diameter is where you resized, the larger "ring" is where the neck wasn't resized.

Is it really a bulge, or is it the dimension of the unsized neck of a fired case? The neck sizing die may not come all the way down to the neck/shoulder junction.

Welcome to inside neck reaming!

You'll have to get a die, or whatever setup to ream the inside of the neck. I had the same problem with my 22-250. I finally ended-up with a RCBS inside reamer die that FL sizes and reams the inside of the neck to .0015" under bullet diameter. It is expensive but makes absolutely perfect cases.

This setup will take a case with any runout, and turn it into one with less than .001" runout, inside and out.

This is commonly referred to as the "donut", or the "dreaded donut" by some.

You can remove it by either of two methods, the inside neck reamer, or you can push the donut to the outside with an expander then turn the outside of the neck and remove it. Best is the inside neck reamer but either work. A less expensive alternative to the inside neck reamer DIE is to have either Wilson or Forster custom make a reamer for either of their trimmers but you have to be precise in your requirement, and it can vary based on thickness of the neck walls of different lots of brass. If you go that route your reamer dimension is the inside of the mouth of the reamer AFTER FL sizing. They charge about $25 per reamer if you go that route.

Thanks gentlemen for your replies to my question about this bulge "donut" on my 338-06 cases. The new question is can I shoot these cartridges safely as is, or must I take them apart and eliminate this "donut" before firing? Also can I correct this "donut " problem by running them through a full length sizing die? Thanks again your advise is appreciated. Chief.

Before going any further, you need to determine if the problem is really a "donut" or just an unsized portion of the neck.

My bet is that the neck is not getting sized all the way down to the shoulder, which is not really a problem at all. In fact, this is actually considered an "accuracy technique" by some because it tends to center the case in the chamber. It is a perfectly safe condition as long as your rounds chamber and extract easily.

What is the neck diameter of a fired case near the case mouth before sizing? Is it the same (+/- .001) as the "bulged" area? If so, the bulge is just the part that's not getting resized.

Why isn't the whole neck being sized? As clever as the Lee Collet Neck die is, Lee has been known to occasionally make things a little "out of spec". Maybe you got a bad die, or a die intended for another cartridge. How long is a .338 Magnum? It wouldn't by any chance be about .136 longer than a 338-06 (head to neck), would it?

I don't know much about donuts, except that they occur at the neck/shoulder junction, but I wouldn't expect a donut to be .136 long and .008 thick. I always thought they were much smaller and took several firings to develop. Do a google for something like '"dreaded donut" case' and you will probably find lots of info, photos of sectioned cases, etc.

Mark is dead on. I didn't read your initial post well enough to note that you were neck sizing with a collet die.

You WILL have a donut when you expand a neck from a smaller case, how bad depends on the amount of brass which goes from the shoulder into the neck of the reformed case and how much thicker the shoulder is than the neck wall. There will always be some donut in expanding up from a smaller caliber and its effect will depend on your chamber. If your neck area in the chamber is tight, the donut can constrict the base a bullet so as to raise pressures significantly and to a dangerous level. In any case, a donut does affect accuracy as it can skew the bullet when it's seated.

Take an expanded case, full size it and seat a bullet. Measure the outside diameter at the base of the neck. Then measure the OD of a fired case. If the dummy with the seated bullet is smaller than the OD of your fired case, you're probably safe but it's not likely you'll have good accuracy. If the base of the bullet seats ABOVE the donut you shouldn't have any problem at all.

quote:

Originally posted by THE CHIEF:
The new question is can I shoot these cartridges safely as is...

Shoot them and enjoy them...

I think that the responses are hitting all around your problem, but no one has scored an "X"-ringer on it yet.

1. If Lee makes a collet die in .338-06, I'm unaware of it, so I assume, like MarkL, that you're actually using a .338 die.

2. Since the .338 has a 25 degree shoulder angle, and the .338-06 has about a 17 degree angle, the base-to-neck dimension is a tad shorter on the .338-06 (by just about the extent of the "donut" on your cases). Hence, the collet die will not size the case neck all the way to the shoulder (not necessarily a bad thing, as MarkL also points out).

3. The diameter of the bulge represents the amount that the neck portion of your chamber is "oversized", ie., how much larger it is than necessary to chamber with the particular thickness of brass you are using. Chamber necks have to be a little oversized, but if you are seeing a noticeable "donut" with partially-neck sized cases (whether the partial neck sizing is done with a collet or conventional die is irrelavant), then your chamber is rather large in the neck area and you should think about finding some commensurately thicker brass.

4. Your donut doesn't likely have to do with the difference in brass thickness at the transition from the shoulder to the neck in the orginal caliber -- if it did, you would find your donut on the inside, rather than outside, of the neck; in which case you could get rid of it by sizing all the way to the new neck-shoulder juncture and inside neck reaming with the proper size reamer.

5. If you want potentially better accuracy (not guaranteed, by any means) and reduced neck working (for longer case life), you might try making your cases from .35 Whelen brass. Necked-down, rather than -up, cases tend to be a little more consistent and the neck wall thickness should be greater (pushing a .358" ring of brass into .338" leaves a thicker wall than stretching .308" brass around a .338" bullet). Starting with .35 Whelen brass also allows you to set the headspace perfectly for your chamber for the first firing, keeping stetching and working down to a minimum.

Happy Hunting!

Gentlemen once again I thank you for your replies. After reading them several times and looking carefully at the cases I do not think I have the "dreaded donut" but rather a situation caused by several factors, namely the 30-06 brass necked up and the use of Lee collet .338 Win dies for this cartridge. I will follow your advise and search for more info on the "donut", then do some additional measuring/inspecting, and when satisfied do as Ricciardelli suggests, shoot and enjoy. I certainly will get some 35 Whelen cases and neck them down as Stonecreek suggested. Hopefully I'll have time this weekend to shoot. Many thanks again. Chief.

quote:

Originally posted by MarkL:


My bet is that the neck is not getting sized all the way down to the shoulder, which is not really a problem at all. In fact, this is actually considered an "accuracy technique" by some because it tends to center the case in the chamber. It is a perfectly safe condition as long as your rounds chamber and extract easily.

I have been experimenting with creating this fire formed bulge like MarkL describes in a 30-06 cartridge. by using a washer on top of the shell holder and a Lee Collet Neck Sizing Die, it leaves that portion of the neck just forward of the shoulder the fire formed size and hopefully will help center the bullet in the throat. No definitive results yet, but it makes me feel better. Have fired 3 firings with these cases with no visible ill effects.


Without guns we are subjects (or victims), with guns we are citizens

When norma makes the case part of the process is to ream the necks. When you expand to .338 a portion of the new neck is formed by the old sholder. What you see is this step -section a few cases and mike the shoulder and neck . If it bugs you a light neck turning will eliminate it.
Glenn