cart SHOPPING CART You have 0 items
SELECT CURRENCY

Discussion Forums

Search forums
Forum Index > Rifles general discussion > Donut by short seating ?

Donut by short seating ?

30 Jun 2020
@ 07:35 pm (GMT)

Anders Österberg

A question
I often see in Nathan's post's that he pointing out that seting the bullet above the junction of the shoulder/neck will create/grow the donut faster.

How can that be..?

My believe in this matter is that the case stretches under pressure and a little amount of headspace.
Then when formed/seizing back to size the stretch out material will move forward and lenght the neck , that then must be trimmed .
Eventually the shoulder material that's thicker than the neck will begin to migrate out in the neck , and that's the donut !

Is it more to this problem that involves how I seat the bullets and to what depth, I wat to get informed ;-)

I'v got the reloading book .

Replies

01 Jul 2020
@ 04:10 am (GMT)

Paul Leverman

Re: Donut by short seating ?
Now there is question to open the proverbial can of worms. Being old and feeble minded, and a very unreliable memory, I had to google the "Dreaded Donut" yet again to refresh the one working neuron that I have left. The result of reading endless postings on just about every website that I visited was this: there are just as many theories about how that donut forms as there are people who are willing to voice their thoughts. Having said that, one thing that I did find consistent throughout all the reading was that the vast majority were the shooters in the benchrest discipline. With this select group of shooters, another factor that was almost always mentioned was the fact that with their chosen calibers they rarely if ever seated their bullets as deep as where the donut forms. The consensus was that if the donut did not interfere, ignore it. The difference being that for hunting cartridges (mine anyway), the donut does cause a problem. Differing neck tension, depending on how mild or severe the donut grips the bullet, will cause irregularities in pressures which in turn will cause differences in velocities. How to check? Slide a bullet into a fired neck. Does it fit? There are only two answers. All the speculation about how that donut gets there, whether it is pressure related or caused by sizing dies or chamber fit or any of the myriad of theories out there is irrelevant (to me anyway). The solution: deal with it. It is only another operation in handloading, takes maybe an additional twenty minutes at the bench to deal with twenty cases. I might be being over simplistic here, but really, if it isn't a problem don't make it one. If it is, fix it.



Having said all this, it is just an opinion.
01 Jul 2020
@ 08:10 am (GMT)

Nathan Foster

Re: Donut by short seating ?
I think for some of these questions, it would be easier if I started doing some of this youtube live or facebook live bullshit. That way I could explain the various factors and generally wank about other factors. But I will need a few punters keen on the idea.

I am not used to, nor taken with the idea of podcasts (or short form blogging). But I think I can put some meat onto the bones of such questions if anyone is keen for this.
01 Jul 2020
@ 09:27 am (GMT)

Martin Taylor

Re: Donut by short seating ?
Firstly, as we have discussed before Nathan some people learn/follow instruction verbally/visually so l think it would be a good thing.

I witnessed cases with very large donuts for the first time a month or so ago. Having never seen this with the thousands of rounds I've reloaded it intrigued me to say the least. After discussing it we worked out that the root cause in this 223 (neck turned Lapua brass) was simply down to reloading technique.
Neck sizing cases only
Partially sizing necks (approx ¾ length)
Seating projectiles very long.

All compounded to cause major problems and the fix in this instance was size the neck completely.
01 Jul 2020
@ 09:49 am (GMT)

Paul Leverman

Re: Donut by short seating ?
Most definitely interested. Am always open to find out why things happen. Usually, I just have to deal with the aftermath the best I can, but if the opportunity arises to not create a problem, I'm all for it.

Martin pretty well wrapped it up. That was the impression I got from all those sites I was on, but between the combatants, it eventually turned into a "mine is bigger than yours", whereupon the page was tossed and I started reading elsewhere.

" Fifteen hundred years ago, everybody knew that the Earth was the center of the universe. Five hundred years ago, everybody knew that the Earth was flat. And fifteen minutes ago, you knew that humans were alone on this planet. Imagine what you'll know tomorrow." K
01 Jul 2020
@ 10:39 am (GMT)

Magnus Vassbotn

Re: Donut by short seating ?
Also very interested.

Like Martin, I just had my first case of serious donuts (also after thousands of reloads). I just bought some supposedly once fired brass, that all turned out to have so much of a donut that they are useless. After close inspection, I can see they have been pressed, so my guess is they have been fired a few times, then tumbled, trimmed and annealed. Decided to bin them and buy brand new ones. First time I've been screwed like that, but it was a small amount and an interesting thing to see, so no big deal. But clearly cunts do exist, even in the healthiest of communities.

M
01 Jul 2020
@ 11:07 am (GMT)

Nathan Foster

Re: Donut by short seating ?
OK, so if I am to try a live feed via youtube, would tomorrow morning 8am NZ time be OK for you guys (Wednesday evening Northern hemisphere)? I am new to this so I could muck it up. I know some of you will be heading off to work in the southern hemisphere, others will be at home but it will be late evening. Or would you all prefer a Saturday morning (Friday evening Northern hemisphere) or Sunday morning (sat evening Northern hemisphere)?

If I do anything visual, it will probably be a pad and felt pen as opposed to graphics - oh yes, so tech savvy.

Will just use laptop web cam.

You will need youtube accounts to log in and make comments on the side bar for me to read.

We can go over donuts, then any other questions - or just long periods of silence because I have not promoted this and therefore only three people will log on resulting in long awkward silences. Riley has however taught me how to do the floss and other dance moves.
01 Jul 2020
@ 04:49 pm (GMT)

Paul Leverman

Re: Donut by short seating ?
For me, the weekend days would be better, either the Friday or Saturday. But I could accomodate the majority.

So do we bring our own felt pens? Who buys the donuts?

Seriously, all I have to do is open/sign in to my Youtube acct? If it doesn't work for me like it should, I will at least be able to listen and watch.
'
02 Jul 2020
@ 06:36 am (GMT)

Magnus Vassbotn

Re: Donut by short seating ?
Friday or Saturday evening (here) would be great,but really most days from around 20:00 will work.
02 Jul 2020
@ 09:07 am (GMT)

Nathan Foster

Re: Donut by short seating ?
Hi guys, I have set up the page. Hope like hell I actually know what button to push when the time comes. Maybe it will just go live automatically and unexpectedly while I am scratching my ...

https://youtu.be/-3955Euww6M

Fingers crossed this does not turn into a complete clusterfk.
03 Jul 2020
@ 02:38 pm (GMT)

Paul Leverman

Re: Donut by short seating ?
Is the link set up so that the video as well as the comments/questions can be viewed later for reference?
04 Jul 2020
@ 07:16 am (GMT)

Nathan Foster

Re: Donut by short seating ?
I think that's how it works Paul. I guess we will soon see huh.
 

ABOUT US

We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.

store