Pumpkin neck turner?

B

Bro.D

Member
When turning necks on stock Lapua 220 Russian brass for a 6 ppc, (.262 neck) how far down the neck do I cut in order to get the neck - shoulder junction at the proper point so that I do not create a donut? Pictures are worth a 1000 words. I don't want to cut too deep causing the possibility of neck separation but cut too short results in the dreaded donut. Where do you stop?
Thanks, Bro.D
 
Bro. D

Since I grind most of my cutters, I like to use a cutter angle a couple of degrees sharper than the actual shoulder angle. I also made my neck turner with an adjustable stop that hits against the shoulder. By doing this, I can thin the shoulder about .003" at the junction down to a blend out about half way down the shoulder. The actual amount of thinning at the junction can be determined by sectioning a case and measuring the thickness at the shoulder just before the junction. Then cut it back by an amount that will make it about .001" thinner than the neck wall. Sometime if you can make it down here (up here), maybe we can custom grind you some cutters for your turning tool (no charge).

Michael
 
Bro D

In some cases I like to turn necks after fire forming to get a nice, clean neck/shoulder. To do so, a friend chambered an old PPC barrel with enough neck clearance to seat and shoot cheap bullets.

While reading the link above the second time, I noticed:

"set up the second trimmer similarly to give a thickness of .0001 to .0003 over your ideal final thickness"

I try for .001" with a 6PPC and about .002" with a 30 caliber. I understand some are getting good results with even more clearance in 30 calibers.

Tony Carpenter
 
The way I set my turner (which is a Pumpkin) is admittedly a pain in the neck, but it does appear to work.

The first thing I do is trim all of my .220 russian cases to the same length before turning. This insures that I don't set the turner for one batch of cases and accidently cut the next set too far into the neck because they came from the factory shorter than the previous cases.

Next I turn a test case then go to the range, fire it three or four times and inspect the case-neck junction carefully inside and out. If the junction looks good (never happens the first time) then all is well. More likely I will adjust the neck turner and repeat several times until it is right.

This obviously requires many trips to the range. It helps that my range is only 5 minutes from my house.

Once I get the turner set I don't ever touch it again. I haven't changed mine in over 4 years.
 
Neck turning...

I was hoping someone could give me a measurement to cut to. Say, "Cut from case mouth towards the shoulder .265 and that should be enough to avoid the donut." Maybe that is unrealistic due to lot differences. My problem is that the lot of brass that I have does not have a descernable neck/shoulder junction...it's more of a radious, so I feel a little lost as to where to stop.
Steve, I may have to take your advise and take all my turnig stuff to the range this weekend. Kind of a pain. If nothing else I can sneek up on the point by trial and error. I hope not too much error.
Might I avoid this situation if I fireformed my brass first with Bullseye casuing the chamber to create a more noticible shoulder???? Then I could cut to that more defined shoulder.
Thanks, Bro.D
 
Here's a picture of a neck which shows BOTH ;) a nicely melded shoulder cut and a deep cut.

Actually, this picture illustrates how a neck/shoulder junction can change from side to side. I grind my cutters to stop cutting when they reach a certain distance up the shoulder, this depth results in a shoulder which matches thickness of a .260 PPC neck. (A neck thickness which results in a .260 dia nk on a loaded round) This photo illustrates how it looks when you turn a .268 neck that's eccentric ........ this is the neck of a 6.5X47L case which has been necked down to 6MM. The necking down always results in a crooked neck. My cutter stops on the neck so when I sectioned this case it shows a nice meld on the one side and what looks to be a deeper cut on the other. When cutting the neck to .260 the two steps look similar.

This cut is not deep enough to ever cause a separation, the brass is still more than .010 thick.

al
 

Attachments

  • 597701516605_0_ALB.jpg
    597701516605_0_ALB.jpg
    17.2 KB · Views: 831
Snuffy,

I don't own a Pumpkin but the way my other three neckturners come from the factory you can't "shine" the necks, they're cut nearly square and they just gouge into the shoulder until they cut clear thru if'n you don't stop 'em!

I agree with you though...... I grind mine to more nearly match the shoulder angle and they'll shine up an eighth inch on the shoulder and absolutely NO chance of a donut.

The attached image shows how the "shine" looks on crooked-necked cases ;) This is from that same series documenting how I made up the 6X47 cases.

On a PPC or BR the cutter will cut a nearly perfect ring feathering out into the shoulder nearly a quarter of the way up........

al
 

Attachments

  • 563064825605_0_ALB.jpg
    563064825605_0_ALB.jpg
    34.2 KB · Views: 548
They look great, AL...

I do use a Pumpkin NOW, but my K&M turner had a beautiful angled cutter and the K&M is very reasonably priced. A vendor on this site made a round holder for the aluminum bodied KM, he called it a arthritis gidget until I pointed out to him that it made a GREAT heat sink. That's the beauty of the Pumpkin, it dissipates the heat. You can cut for a while and it won't get hot. Some shooters dip the KM in alcohol to cool it. I hope the original poster sees this photo....REMEMBER, it ain't rocket science, although some newbies might think so. I know that I did too at one time.

PS. I make one slow cut now, it just seems to be less chance of error

"Snuffy"
 
Last edited:
Doughnut

Bro.D said:
When turning necks on stock Lapua 220 Russian brass for a 6 ppc, (.262 neck) how far down the neck do I cut in order to get the neck - shoulder junction at the proper point so that I do not create a donut? Pictures are worth a 1000 words. I don't want to cut too deep causing the possibility of neck separation but cut too short results in the dreaded donut. Where do you stop?
Thanks, Bro.D
Click to expand...

I had a neck come off of a case and get stuck in the neck bushing. This happened during the first match of the day. I decided to let the doughnut form from now own. The cases shoot just as well as the ones without a doughnut as best as I can tell. Here is a photo of a five shot group using cases that have a significant doughnut. Group was shot with a Rail Gun in favorable conditions. Who knows, the cases may be stronger. I have shot cases with a doughnut all this year. My chamber has a .270 neck. Seems to work okay...........GW

2hq8jv9.jpg

I now stop the cutter at the junction and barely touch the shoulder.
20pc8zr.jpg
 
Nice group!

Gary, that is an awesome group. What did it measure? I have had many dreams of that small of a group forming in my scope, but usually after the second shot it begins to grow. From your example, the donut may not be as vital as once thought. Maybe I'm too up tight about the small things, but I've always thought you ought to do what you can to help yourself shoot small. Neck seperation is still a concern so I'll be testing some different things this coming weekend to help avoid it. Thanks, Bro.D
 
Gary,

I agree with the donut not being a problem.... EXCEPT when one's shooting with bullets seated deeply into the neck. My 6BR/6X47 loads are set up to where the boattail hangs down into the powder.

Regarding the "donut", I've got a shortened .308 which has a donut .200 long! I just rammed the shoulder back and left the neck on it. It shoots fine UNLESS you try to put a 125gr in it ......... NO! NO! NO! ..... 112-118's ONLY!


Snuffy,

My old K&M doesn't cut as nice a "shine" or feather as I'd like, it's angled some but sharp, not radiused the corner.

al
 
You must log in or register to reply here.
Back
Top