quote:

...when seating the bullet the press will seat the bullet past the do-nut with no discernable effort, but what effect will it have?

quote:

Originally posted by steve4102:
What's a Do-nut?

quote:

TURN TO THE SHOULDER.... I have very carefully dressed the tool bit with a fine diamond hone so that the cut on the outside of the neck looks like polished brass. I also made a small fillet radius (approximately 0.010" radius) on the leading edge of the tool bit that matches the fillet at the neck to shoulder junction on new brass. I turn the neck so that the bit cuts slightly into the shoulder approximately 0.002" to 0.004". I have had no necks separate from the shoulder from doing this and it decreases the chance of developing the "dreaded doughnut" (a constriction of the neck ID at the neck to shoulder junction).

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K & M has specially designed a new carbide mandrel that has four flutes for removing the "dough-nut" that is located at the neck-shoulder junction of a case. Removing this extra material aids in a consistent high volume flow of powder gas. A small difference in the shape and diameter of the hole makes a huge difference in performance. This new carbide mandrel will also cut the extra material out of this area if you have changed the neck to a different caliber. This mandrel works while you neck turn, so you will not have to perform a separate operation.
To Order, Click on the Item Number.

KMCAP17
.17 CARBIDE PILOT
$37.15
(0.2 LB)

KMCAP19 .19 CARBIDE PILOT $37.15 (.02 LB)
KMCAP20 .20 CARBIDE PILOT $37.15 (0.2 LB)
KMCAP22 .22 CARBIDE PILOT $37.15 (0.2 LB)
KMCAP6MM 6 MM CARBIDE PILOT $37.15 (0.2 LB)
KMCAP25
.25 CARBIDE PILOT
$37.15
(0.2 LB)

KMCAP65MM 6.5 MM CARBIDE PILOT $37.15 (0.2 LB)
KMCAP27
.27 CARBIDE PILOT
$37.15
(0.2 LB)

KMCAP7MM
7mm CARBIDE PILOT
$37.15
(0.2 LB)

KMCAP30
.30 CARBIDE PILOT
$37.15
(0.2 LB)

KMCAP338 .338 CARBIDE PILOT $37.15 (0.2 LB)

quote:

Have you looked into using Forster's reamers?

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Thick case necks can cause high chamber pressures and flyers. The Forster Neck Reamer mounts in the cutter of a Forster Case Trimmer in place of the pilot and removes the excess brass from the neck walls. The Forster Neck Reamer is manufactured from high grade, wear-resistant tool steel and ground .0025" to .003" over the maximum bullet diameter. The staggered tooth design cuts the brass smoothly without chattering.

Three important notes about using your Forster Neck Reamer:

Neck reaming should only be performed after the cases have been fired with a full load and before the neck or full length sizing operation. Wall thickness can be measured with a tubing micrometer, but a simpler test for excess brass in the neck area is to slide a bullet into a fired, unsized case neck. If you feel interference, the neck should be reamed or outside neck turned.


Use neck reamers before resizing. Three exceptions to this rule are the NR1220-.220" diameter reamer for .224" bullets; the NR1239-.239" diameter reamer for .243" bullets; and the NR4275-.4275" diameter reamer for .429" bullets. These are common sizes that reloaders use to ream their cases just before seating bullets. These three sizes are kept in stock for those who intend to ream after the sizing operation just before seating bullets.


We grind many other special sizes as needed. Wildcatters often require specially sized reamers when converting brass from one caliber to another. You tell us the size you need and we'll grind it to your exact specifications. A nominal $10 special grinding fee applies. Our quick turnaround service adds a versatile case preparation tool to your Forster Case Trimmer System.

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Originally posted by woods:

I already have the Forster turner and like it just fine.

Maybe they sell a reamer that would attach to my neck turner.

quote:

Originally posted by woods:
I also made a small fillet radius (approximately 0.010" radius) on the leading edge of the tool bit that matches the fillet at the neck to shoulder junction on new brass. I turn the neck so that the bit cuts slightly into the shoulder approximately 0.002" to 0.004". .

quote:

Originally posted by woods:
Yeah, but my Forster neck turner is the hand held neck turner.

...the listing for "Hand Held" HOTP284 would fit my hand held turner.

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Originally posted by pointblank:
Woods,

In my first post on this subject I told you how to get rid of the donut on the cases you are dealing with now and to not have the donut problem in the future for new cases.

For the cases you are dealing with now: Resize the cases setting the shoulder back a little farther than normal. You have created a "false" shoulder that you can now run the turner into. Now expand the necks like you would normally for
neck turning. OK, now the donut is on the outside of the neck, simply turn it off running the neck turner into the shoulder. Now when you fireform this brass, the shoulder will move forward to its original location but the cut will be further back in the shoulder. In the life of that brass(unless its Lapua), the brass will not flow enough forward to create a new donut. Do this on new cases as well and don't worry about donuts.

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Originally posted by woods:

quote:

Originally posted by pointblank:
Woods,

In my first post on this subject I told you how to get rid of the donut on the cases you are dealing with now and to not have the donut problem in the future for new cases.

For the cases you are dealing with now: Resize the cases setting the shoulder back a little farther than normal. You have created a "false" shoulder that you can now run the turner into. Now expand the necks like you would normally for
neck turning. OK, now the donut is on the outside of the neck, simply turn it off running the neck turner into the shoulder. Now when you fireform this brass, the shoulder will move forward to its original location but the cut will be further back in the shoulder. In the life of that brass(unless its Lapua), the brass will not flow enough forward to create a new donut. Do this on new cases as well and don't worry about donuts.

pointblank

I am not ignoring you. I would rather have the donuts on the present cases then push the shoulder back that far and have additional thinning at the web. They are not hurting anything right now, maybe accuracy but probably not. The do-nut is only .001" on the present case.

I do turn the necks as far back into the shoulder as possible before the first firing. Pushing the shoulder back farther and creating excess headspace to get an additional amount of turning is not an option I would like to do now.

Seems like the Forster neck reamers are exactly what I need but I have to talk myself into spending that much. The reamer being .0025" to .003" is exactly what is needed which shows the Forster people are on the ball as usual.

If you neck turn the brass so that there is .003" clearance around the neck then the inside neck diameter after firing should be .003" larger than caliber diameter and the reamer should fit tight and get rid of the do-nut.

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Originally posted by pointblank:

to cure your excessive headspace thought, which won't really exist if you only bump the shoulders a couple thousanths

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I turn right down to the neck shoulder junction. The new case shoulder datum point is at 2.135" and it expands to 2.150" which allows .015" of movement forward by the shoulder. This should be enough to get the turned neck brass onto the do-nut area.

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go ahead and ruin the concentricity of the necks you turned to get them concentric

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I have managed to not blow myself up in 20 years of dealings with tighneck chambers and wildcat chamberings.

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Originally posted by woods:
...If it doesn't work then I will throw it in the drawer with the rest of the "thingys" (you there HC? ), but believe me I will be the first to know if it affects concentricity at all, if the RCBS casemaster doesn't show it then the Bersin Tool will. IME, if you want to destroy concentricity then start expanding necks. ...

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Originally posted by Hot Core:
Yes, I'm following along as best I can.

Only problem is, I don't have any of these problems with good old P-FLR. Huuuummm:
1. Maybe I do have do-nuts in my Standard Cartridge Chambers and don't even know it.
Probably so, factory chambers expand the case a lot more than tight neck chambers and you can't look for it after sizing since the bullet won't slide down the neck by hand anymore. We'll just have to put do-nuts on your very long list of "things you have and don't even know it."
2. I don't have an RCBS Casemaster.
Probably a good thing, you might hurt yourself!
3. I don't have a Bersin Tool.
You sure you can't make your own out of baling wire and duct tape?
4. I don't have any "Thingys".
Hell to get old and not have a thingy anymore, my sympathies.

But I can still shoot in the 6s(on good days).

quote:

Originally posted by woods:
[QUOTE]Originally posted by Hot Core:
2. I don't have an RCBS Casemaster.
Probably a good thing, you might hurt yourself!
4. I don't have any "Thingys".
Hell to get old and not have a thingy anymore, my sympathies. Hey HC ! I think you're being put upon. roger

Somebody's got to figure out what makes things tick for all you lucky consumers out there.