A 'delumping' die for 30BR cases

[AlNyhus]

Here's another way to deal with the 'lump' after expanding 6BR cases to .30.

A Redding 7BR Body Die has a .311 opening for the neck. So I took one of those:

Added an 'o' ring under the lock ring and screwed it into my 'stub' threaded 7/8-14. The 'o' rings allows for a bit of self centering.

With the stub and die in the chuck, it was time for this. It's a stepped carbide chucking reamer that's .311-.327. The .311 registers in the hole through the die and the .327 section cuts the neck portion to .327.

After opening up with the reamer:

The internal finish of the new neck is pretty nice as verified by bore scoping. I did a light bevel on the inside of the die at the neck/shoulder junction with a 30 degree tapered stone:

This is a Lapua 6BR case expanded to .30. Checking the run out, it's right at .0045...pretty normal after mechanically expanding the neck.

After running the case through our new fixed neck dimension die, here's what we get. You can see the 'lump' has been reduced in external dimension:. Leaving the 'o' ring under the lock ring allows some float and lets you adjust the die down until you've gone past the 'lump'. With a pin gage, there's no more tightness at the neck/shoulder junction than before going through the die:

Run out after going through the die:

Then I just went over a .3070 expander and turned the case on a .3060 carbide mandrel like normal. Post turning, the neck shows minimal run out:

I ran the cutter down the shoulder a bit more than normal to show how even the cut was at 180 degree intervals. Excessive neck run out would show the wavy cut you get when there's excessive neck runout prior to turning.

Hope some will find this helpful. -Al

 

[jimmymac]

You have all the cool tools!

 

[AlNyhus]

You have all the cool tools!

Should post a pic of my lathe I did it on.....

 

[expiper]

Al...you are a pretty handy guy--Roger

 

[jimmymac]

Should post a pic of my lathe I did it on.....

I should have listened to you yesterday and went with the 323 bushing!

 

[AlNyhus]

Al...you are a pretty handy guy--Roger

Thanks, Roger. Like Red Green says: "If the women don't find you handsome, they should at least find you handy."

 

[jobhopper66]

Mr. Nyhus always has some of the most useful advice and ideas and it never ceases to amaze me the people on here that don't see that and still want to argue. It certainly helps that he has a very enviable set of shop skills.

 

[Henryrifle]

Hi, Al. Are you holding the stub with a collet or some other 3,4 or 6 jaw chuck? I am impressed that the expanded neck is so concentric to the body. Interested in how you are achieving that.

As always, nice work and thank you for sharing!

Hank

 

[AlNyhus]

Hank, just a small 3 jaw chuck. At times, a light stress relieving of the neck/shoulder junction helps before putting the cases into the die. Seems like it depends on the brass.
Thanks for the nice compliment, sir.

 

[JoeDuke]

Al do you have any interest in making those for sale?

 

[AlNyhus]

Al do you have any interest in making those for sale?

Joe, I'm working with something that might even be easier. Hang tight for a few days and I'll post the results. -Al

 

[JoeDuke]

Always fun to watch your projects Al.

 

[AlNyhus]

FWIW, I finished up fifty new Lapua 30BR cases for my Kreiger barrel this morning with the 'delumping' die.
-Up to .30 with Redding tapered expander
-Into the delumper die
-Expand over a .3070 mandrel
-Turn on carbide .306 mandrel in one pass

After going in the delumper die and over the .307 expander, there were a couple necks right at .0025 TIR. The rest were right at .0015 TIR with a good number under that. Blending into the shoulder with a 35 degree cutter, even the .0025 run out cases showed no 'wave' on the shoulder blend. The runout on the .0025 necks was under .001 after turning indicating it was more neck.thickness inconsistency on those cases than anything.

Next step will be drawing back the cases, a good scrubbing in hot water and Dawn followed by a soak in acetone. At that point, they'll be ready to f.l. size with a bushing and be ready to go.

 

[jimmymac]

If you decide to make a few for sale, I'd like to buy one please. Thanks.

 

[Bill Norris]

FWIW, I finished up fifty new Lapua 30BR cases this morning with the 'delumping' die.
-Up to .30 with Redding tapered expander
-Into the delumper die
-Expand over a .3070 mandrel
-Turn on carbide .306 mandrel in one pass

After going in the delumper die and over the .307 expander, there were a couple necks right at .0025 TIR. The rest were right at .0015 TIR with a good number under that. Blending into the shoulder with a 35 degree cutter, even the .0025 run out cases showed no 'wave' on the shoulder blend. The runout on the .0025 necks was under .001 after turning indicating it was more neck.thickness inconsistency on those cases than anything.

Next step will be drawing back the cases, a good scrubbing in hot water and Dawn followed by a soak in acetone. At that point, they'll be ready to f.l. size with a bushing and be ready to go.

Please check your P M Thanks.

 

[AlNyhus]

So this morning I made another fifty 30BR cases...this time for a new Bartlien. When I was packing stuff away it dawned on me that pics are worth a thousand words. Here's the gear I use.
-Top left-rt: 300 Weatherby die used for expanding necks...it's just a holder for the expander next to it that has a Redding 6-30 tapered expander on it. Next is the .327 'delumper' die. Then a Sinclair expander body and a 21st Century .307 expander ('delumped' cases go over the expander prior to neck turning). The bottle of red secret sauce is my turning lube brew. Lots of stuff works but when turning under power, you want something other than Imperial.
-Bottom from left- PMA turner with .306 carbide mandrel and 35 degree cutter. You want a cutter that's 5 degrees over the shoulder angle when you're blending into the shoulder so you don't get a 'ridge'. Next is a good Mitutoyo .0001 micrometer. Then the power driver with a Sinclair case driver that registers in the small flash hole. I like the Worx 20V because it's a two speed. On high speed, it's just right for neck turning. I hate feathering the throttle when turning necks...this one I can just put it on the mat and not worry about it. I go on fairly briskly and come off about three times as slow to get a nice bit of 'fuzz' on the way off the mandrel. Final results are on the far right.

 

[Sandstorm]

Al...Is that fake butter and transmission fluid your using for lube.

 

[AlNyhus]

Al...Is that fake butter and transmission fluid your using for lube.

50/50 mix of Marvel Mystery Oil and Mobil 1 0W-20 wt. The spray butter pump bottle is full of 91% rubbing alcohol.

 

[AlNyhus]

Next stop was a draw back of the cases. High tech stuff is pretty seductive. Try to not get all turned on by this setup.

If you're thinking about making up something like this delumper, don't get all hung up on run out numbers. The advantage this gives is managing the 'lump' so you can turn the necks in one pass and not struggle with the internal donut at the bottom of the neck.

Good shootin' -Al

 

[Silo1616]

Next stop was a draw back of the cases. High tech stuff is pretty seductive. Try to not get all turned on by this setup.

If you're thinking about making up something like this delumper, don't get all hung up on run out numbers. The advantage this gives is managing the 'lump' so you can turn the necks in one pass and not struggle with the internal donut at the bottom of the neck.

Good shootin' -Al

Can you see a color change in the brass with that burner nozzle set-up? or are you relying on time only.