30-284?

436

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Let's see, we know the .30-284 Win is quite the cartridge for target and game, the .338-284 Win is a very useful game getter, and I sure the .35-284 Win would be fun to play with in the game field. So, any anyone tried the 8mm-284 Win yet. I once considered building one in a Win Mod 88 that I had in the .284 Win that I had in the '70s. Perhaps someone here did and would like to elaborate on it. It would sure seem to have everything needed ballistically. I'm not trying to get off subject here just curious. Cheers.
 

Roughrice

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Can you provide a link to the T handle you use?

And is the donut in the neck visible? I didn't think I had one
Donut is barely visible when looking with naked eye... I get one after several loadings on a 6.5 284 with Lapua brass that has not been necked up. You can feel it when slipping a bullet deep into neck of an un-sized fired case.
My bullet's bearing surface seats above it so I really don't worry too much. What I do worry about is the case separation that I've once had about 1/2" above the base of the cartridge. Gets your attention!! I now check with paperclip tool when I see the shiny ring developing in the same area on cases. Haven't had it happen since.
 

Tac-O

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Let's see, we know the .30-284 Win is quite the cartridge for target and game, the .338-284 Win is a very useful game getter, and I sure the .35-284 Win would be fun to play with in the game field. So, any anyone tried the 8mm-284 Win yet. I once considered building one in a Win Mod 88 that I had in the .284 Win that I had in the '70s. Perhaps someone here did and would like to elaborate on it. It would sure seem to have everything needed ballistically. I'm not trying to get off subject here just curious. Cheers.

I like that idea. I was thinking that at some point I'd like to get another Tikka rebarreled to a 338-284, 35-284, or 8-284, in a 20" and put some iron sights on it :)
 

Tac-O

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Donut is barely visible when looking with naked eye... I get one after several loadings on a 6.5 284 with Lapua brass that has not been necked up. You can feel it when slipping a bullet deep into neck of an un-sized fired case.
My bullet's bearing surface seats above it so I really don't worry too much. What I do worry about is the case separation that I've once had about 1/2" above the base of the cartridge. Gets your attention!! I now check with paperclip tool when I see the shiny ring developing in the same area on cases. Haven't had it happen since.

Interesting. I'll have to do some reading on the donut. I guess I don't know much about it. I just thought it was formed when necking up a case and that it would be alleviated after the first firing and resizing
 

Tac-O

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Brad called me back this morning, which was nice as that was a pretty prompt call return.

He said he'd try to refinish, or home, the chamber again and that might get me an extra half thou in the chamber. He said he'd also run a throating reamer through it to give me some more room for bullet seating.

I'll be taking him my gun and a couple of cases and bullets later this week.

So, I'll at least be able to get the throat fixed and hopefully will be able to chamber easier.
 

Tac-O

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No they don't go away. Two ways to combat them:
Use a mandrel to push them out (works for a little while) or, 2 inside neck ream and remove them.
So the donut forms on the inside?

Have any links to threads where it's discussed at length? I'm sure there's probably quite a few
 

Tac-O

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I see.

I found a decent thread that explains why it happens, sort of. I understand that when FL sizing it moves the brass up into the neck. But why wouldn't it just flatten out during normal sizing/firing operation?

A couple of questions I couldn't find answers to in searching.

1. Is the donut only formed in certain case types or certain methods of sizing?

2. Do donuts commonly occur in various saami cartridges where the correct headstamp brass is used (not necking up or down)?

3. Is the dreaded donut likely to be a problem for me in this cartridge scenario using the same sizing procedure I always have just because it's a 284win case necked up to 30? (FL sizing by 0.002 shoulder bump each firing and annealing every 3 firings)

My method of prepping this 284 brass was the following:

1. Used Lyman M 308 expander die to expand necks

2. FL sized the cases with a 30-284 rcbs die set to where it bumped the shoulder 0.001 or less. I left the expander ball in the die. I always FL size virgin brass to make sure they're all uniform.

I haven't verified that my brass has a donut. But, I couldn't see one on the outside of the necks and it felt normal when seating the bullets (bullet base went below neck/shoulder junction).

I am now worried that I'll have to start neck turning. I really don't want to add another step to brass prep, I don't have a neck reaming or turning tool, and my wallet is empty!
 

338 dude

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I see.

I found a decent thread that explains why it happens, sort of. I understand that when FL sizing it moves the brass up into the neck. But why wouldn't it just flatten out during normal sizing/firing operation?

A couple of questions I couldn't find answers to in searching.

1. Is the donut only formed in certain case types or certain methods of sizing?

2. Do donuts commonly occur in various saami cartridges where the correct headstamp brass is used (not necking up or down)?

3. Is the dreaded donut likely to be a problem for me in this cartridge scenario using the same sizing procedure I always have just because it's a 284win case necked up to 30? (FL sizing by 0.002 shoulder bump each firing and annealing every 3 firings)

My method of prepping this 284 brass was the following:

1. Used Lyman M 308 expander die to expand necks

2. FL sized the cases with a 30-284 rcbs die set to where it bumped the shoulder 0.001 or less. I left the expander ball in the die. I always FL size virgin brass to make sure they're all uniform.

I haven't verified that my brass has a donut. But, I couldn't see one on the outside of the necks and it felt normal when seating the bullets (bullet base went below neck/shoulder junction).

I am now worried that I'll have to start neck turning. I really don't want to add another step to brass prep, I don't have a neck reaming or turning tool, and my wallet is empty!
Don’t forget you will also need to buy an expanding mandrel set up to push the extra metal outward before you can even turn it off or you can ream the inside of the necks but that is also something else to buy
 

Tac-O

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Don’t forget you will also need to buy an expanding mandrel set up to push the extra metal outward before you can even turn it off or you can ream the inside of the necks but that is also something else to buy

I do have the Lyman expanding mandrel die. From what I found in researching before buying it, it's pretty much the same as the ones others like to use, like the KM mandrels, right?
 

Roughrice

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If it felt good when seating... you'll be fine for a while.
Like GLTaylor said... Using your Mandrel will push em out of the way for a short while but eventual inside turning would alleviate the problem for several more loadings.
You may get several reloads in before it shows up.
I'm using factory Lapua 6.5 and I still get a small donut after several loadings.
I really think its just the nature of the beast...Only that necking up may show up quicker.
I've felt em in other calibers as well after several loadings.
Don't get derailed!! Keep the path! It'll be interesting and fun!
 

Roughrice

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Shoot that bad boy and give us a report!
Then... slip that bullet into that fired case and see what it feels like when it gets to the donut area.
 

Tac-O

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Shoot that bad boy and give us a report!
Then... slip that bullet into that fired case and see what it feels like when it gets to the donut area.

I shot on Saturday for break and testing... It will definitely shoot if I can get the chambering/extraction issue resolved!!

I got tired of doing the cleaning/break in after about 7-8 rounds, so I used the remaining 5 I had loaded for that process (just a starting charge of 4451 and Hornady interlocks) and fired them pretty hastily to see what it would do and they were all within 3/4". That's with my cracked laminate stock and not taking my time to try to put them all in the same hole. So... Yea I'm confident it will do well since I got those crown burrs knocked off haha. I was frustrated at that point so I just wanted to shoot.

The the others I shot were loaded for load testing. 150gr Sierra flats. 5 groups of 3 charges. 3 of the loads had 2 touching and one about 1/2" off the group. The other 2 charges were right around 1" I think.

Looking at neck turning/reaming, if I DO have to start doing that, I was thinking these two pieces would work to turn the outside neck and cut off the donuts if they form.

Km neck turning rool
Km carbide cutting pilot

Would I need anything other than those two pieces? I see there is an expanding mandrel iron tool, but not sure I'd actually need that if I have a neck expander already. I think the mandrel on my Lyman expander is .3065 or something close
 

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