a ring inside case neck.

[Deleted old_dood]

just noticed this. It's a very fine raised ring at around the base of the neck, just above the shoulder. It's deep enough to not cause a problem seating bullets. Should I be concerned? How'd this happen?

Al

 

[ThunderDownUnder]

Its commonly called a donut and its pretty easy to remove with an inside reamer if it is a problem. Lots written on this site about them and all you need do is a search of the forum to find out everything you want to know.

Ian

 

[BoydAllen]

Given your description, I would ignore it.

 

[thumper4fun]

Given your description, I would ignore it.

+1

 

[lpreddick]

old__dood: this ring is often referred to as "the dreaded donut". as noted it's not a real problem unless you seat a bullet into or thru it. i tried "ironing" them out in a 6.5-284 case using a bullet...the ring compressed the bullet! a neck reamer will remove it and even this can be a slight struggle if using a wilson neck reamer. a lot has been discussed here about cause etc. they seem to occur more commonly in some cases. question: how common are the y in 6 PPC and 6 BR?

 

[Deleted old_dood]

Given your description, I would ignore it.

thanks, will do.

 

[fdshuster]

Al; Just make sure you're not seating the bullet on top of the donut.

I take an as fired case & drop the bullet I'm going to seat into the case neck. If it falls all the way in to the case, no donut. If the bullet stops with the full diameter base at the neck/shoulder junction, I then take a length measurement with the Stoney Point Chamber O.A.L. gauge, and record that number. For example, it may be 1.556". When seating the bullet, I then want to see a longer dimension than that 1.556". Without the S.P. gauge you could just measure off the bullet tip, but there would be some error because of differing bullet over-all-lengths.

 

[Deleted old_dood]

Al; Just make sure you're not seating the bullet on top of the donut.

I take an as fired case & drop the bullet I'm going to seat into the case neck. If it falls all the way in to the case, no donut. If the bullet stops with the full diameter base at the neck/shoulder junction, I then take a length measurement with the Stoney Point Chamber O.A.L. gauge, and record that number. For example, it may be 1.556". When seating the bullet, I then want to see a longer dimension than that 1.556". Without the S.P. gauge you could just measure off the bullet tip, but there would be some error because of differing bullet over-all-lengths.

it's well beyond where I seat them. What about the expander button in the die. I've got the Redding S die with the carbide expander.

 

[fdshuster]

Al: "It's well beyond where I seat them". If you mean the bullets are not contacting the donuts because they (donuts) are deeper in the case neck than the full diameter of the bullet, then I would not, and I do not, worry about them.

I've just spec'd a new 308 chambering reamer from PTG and that was one of my main considerations: the seated bullets that I plan on using (175 SMK's) can be seated to touch the lands, and I can even give them a little "jump", and that bullet (the longest/ heaviest I plan on using) will be in front of the donuts.

With my Redding type S bushing dies, I never use the expander. Not needed when the case necks are not being oversized ( squeezed down overly small), as they are with a conventional sizing die.

 

[lpreddick]

is this a "false" donut? i have a tight neck 6mmBR. i seat the bullets .020 into the lands, over half of the neck is below the pressure ring noted in the neck. after firing and cleaning carbon out of the neck(no neck sizing) i can insert a bullet into the case mouth and as it goes deeper in the neck there is a point where the bullet's pressure ring stops the insertion and this point is just above the neck/shoulder junction, slightly beyond where i'm accustomed to encountering "the dreaded donut". neck brass thickness seems to thicken ever so slightly as you go from case mouth to the shoulder and being tight necked(.2704) i believe i'm seeing this normal occurence and not a real donut. i have noted increased resistence to seating if i seat a bullet to this point as opposed to seating one thru a true donut. reaming a true donut leaves a very bright narrow ring just at the shoulder/neck junction as noted with my borescope.

 

[P1ZombieKiller]

One little trick to help is to turn your necks slightly into the shoulder. This way when you fire it, and the shoulder gets pushed forward, it's not as thick. Here is a close up of one of my pieces of brass right after turning.