Ring around the neck question

[BML]

My 6.5x284 Norma brass is developing a ring around the neck right at the base of the shoulder. I did a little research and I think it's what is called the "donut".

Does anyone know what causes this and how to I fix it? The ring is noticeable on the inside of the brass as well. So far I haven't had any issues with bullet seating past that ring but I have noticed that when I neck size, it's very difficult to pull the brass back out of the die. I am assuming the ring is causing the hang up.

 

[Trnelson]

My 6.5x284 Norma brass is developing a ring around the neck right at the base of the shoulder. I did a little research and I think it's what is called the "donut".

Does anyone know what causes this and how to I fix it? The ring is noticeable on the inside of the brass as well. So far I haven't had any issues with bullet seating past that ring but I have noticed that when I neck size, it's very difficult to pull the brass back out of the die. I am assuming the ring is causing the hang up.

Yes you have the "donut" it sounds like. How many times have you loaded the brass? Have you tried full length sizing to remove it? Check if the brass is thinning out right above the web with a wire. There's some migration going on either from repeated neck sizing or flow from pressure. The donut can cause excessive pressure if your chamber is tight it acts like a clamp on the bullet. You may need to turn the neck to remove the thickened portion of the neck. YMMV

 

[BML]

It started around the 10th or 11th time I fired the brass. I full length sized them and it didn't go away. I neck size every time. I'm only shooting 48g since my gun does not shoot well with hotter loads so I'm assuming It's not a pressure issue. The only time I turned the necks is right out of the box before ever firing them.

 

[Trnelson]

I would lean toward the brass being worn out. With 10 load cycles it is most likely getting pretty thin at the case head above the web and pretty hard at the neck. I would just retire it before it splits out and start again with fresh brass. I shoot the similar 6.5/06 and typically retire the brass after 8 cycles. I had some cases that split above the web on the 9 cycle before i learned how To check for thinning there. I suspect it may have been work hardened, and in need of annealing as I had a couple cases from that batch split their necks at the end of the 8 cycle. Could have been a disasterous learning experiance. I run the 140 Berger vld at 2,900fps so like you I'm not trying to extract every ounce of speed that I can get out of the loading. I'm using .270 necked down and trimmed to length. I prefer the .270 over .25/06 necked up as the .25/06 stretches .003 to .004" on first firing and only holds up for 5 to 7 cycles. I neck size after initial full length sizing just as you do. Just my opinion YMMV.

 

[BML]

I'm shooting Norma brass and at that price I was expecting longer brass life than that. So I have a couple questions then when I start over with new brass. First is what can I do, if anything, to extend my brass life? Second, none of my new brass has been fire formed yet. What kind of effect on my grouping should I expect on the first round with that brass?


Thanks for the tips. I appreciate it!

 

[Trnelson]

Norma brass is real good stuff, but ten cycles is alot of metal moving. Have you had to trim it? How are your primer pockets holding up? I would first check your thickness above the web to make sure it is still safe to continue loading. If it is thining more than .0015 recycle it. Check the thickness of the brass at the neck as well with the same standard in mind. If that checks out ok I would anneal it and then full length size it and turn the necks to get rid of any remaining donut. After all that you will most likely only get two maybe three more cycles before you get split cases. The Norma brass is about as good as one can get and it has nicely annealed necks from the factory but each time you load and fire it work hardens the brass, the metal that formed the donut migrated from either the neck or the case body and has "gathered" right at the neck and shoulder junction. IMO your not pushing the limits of sane pressure but all things wear out eventually. I only get 8 cycles out of the Winchester .270 brass I use so I completely understand your frustration. I get only 5 cycles if I use .25/06 brass the worst part is I have to spend time to anneal it and then size it and sort it by weight as the cheap brass can vary by several grains. So out of 100 pieces I usually end up with 75 to 80 that are identical and the rest are various weights that I set aside until I can accumulate enough to make it worth loading. The Norma stuff is pretty well size it and load it without a lot of wasted time. I'm going to try the Nosler Custom .270 brass to see if it lasts better. YMMV

 

[BML]

I put every piece through the trimming process before loading every time, but I've only had to remove material twice so far. I will more than likely remove a little material the next time I load them as well.

Primer pockets are fine. I haven't noticed any loose primers or swelling.

Neck thickness on a new unfired piece is .015 and it's .015 on a piece of unprepped brass that I just fired.

Forgive the ignorance but I'm not sure which part of the case is considered the web so I'm not sure where to measure there.

 

[Gene]

Web is at the bottom, just above the extractor rim. You can inside ream the neck to remove a donut, but as long as the bullet base does not touch it, just let it alone.

 

[Trnelson]

The web is the part ahead of the primer pocket. You'll want to take a stiff piece of wire and insert it into the case. You want to feel along the inside of the body for irregularities, rough spots, thin places or thick spots. You can also shine a bright light inside and visually inspect a clean case if you ultrasonically clean your cases.

 

[Trnelson]

The web is the part ahead of the primer pocket. You'll want to take a stiff piece of wire and insert it into the case. You want to feel along the inside of the body for irregularities, rough spots, thin places or thick spots. You can also shine a bright light inside and visually inspect a clean case if you ultrasonically clean your cases.

Here's a classic case split right above the web. This gentleman had this failure after three loads according to his post.

http://www.longrangehunting.com/forums/attachments/f28/9074d1336087399-brass-failure-0503121712.jpg

 

[BML]

That's a good picture. Thanks for sharing.

I just measured it. Brand new unfired is .498. An unprepped piece measured at .500 even. Is there a chart or some publication somewhere that lists the tolerances and when those numbers become on the edge of the limits?