30BR cut too far into shoulder?

[TommyD11730]

Extreme closeup.... after 6 firings I notice this Black carbon ring on the brass. You can "feel" the ring with your fingernail.

Im wondering if I cut too far into the neck when turning.

With little 30BR experience not every piece looks like this. However enough of them for me to be ready to pitch the lot.

So should I pitch this lot of brass?

 

[Bill Norris]

Looks like you did cut pretty deep into the shoulder. It may come apart with continued firings.

 

[TommyD11730]

Looks like you did cut pretty deep into the shoulder. It may come apart with continued firings.

Thanks Bill... live and learn

 

[AlNyhus]

TommyD, a couple things to keep in mind as you go forward:
-A cutter angle that's more than the shoulder angle will eliminate the 'dig in' line and give you a smooth blend. My preference is a 35 degree cutter.
-It's unusual to see powder residue on the shoulder. Make sure that you're not bumping the shoulders excessively and/or using too light a load. Double check the neck clearance, too...could be a combination of things going on here.

Hope this helps. -Al

 

[bugman]

Extreme closeup.... after 6 firings I notice this Black carbon ring on the brass. You can "feel" the ring with your fingernail.

Im wondering if I cut too far into the neck when turning.

With little 30BR experience not every piece looks like this. However enough of them for me to be ready to pitch the lot.

So should I pitch this lot of brass?

Here is my 2 cents.......

Before you ditch all that brass, use a dremel and section one case lengthwise. You will notice a "ditch" internally and opposite the external area. If that "ditch" is less thick than the surrounding brass thickness of the neck and the shoulder immediately below it, ditch the brass or deal with the imminent neck separations.
If there is no internal "ditch" and brass thickness is the same as the other areas of the NECK, then you probably used too acute of a cutter angle. In this case, the increased shoulder brass thickness (even with the outside "dig) should be sufficient to prevent separations.

Either way, unless you are really jumping bullets, you don't need to turn onto the shoulder that far.

 

[Shooter13]

You will lose those necks ........... eventually. Take it from one with experience (in losing the neck). My first cutting job was to far down on the neck, I'd eject the case and there was no neck at all OR half the neck left. Not fun or a pretty sight! We try, we experiment and hopefully learn! I learn with every new experience, by the time I'm 100 years old I should have it down .............. or be dead, probably dead. Have a blessed day!!

 

[TommyD11730]

TommyD, a couple things to keep in mind as you go forward:
-A cutter angle that's more than the shoulder angle will eliminate the 'dig in' line and give you a smooth blend. My preference is a 35 degree cutter.
-It's unusual to see powder residue on the shoulder. Make sure that you're not bumping the shoulders excessively and/or using too light a load. Double check the neck clearance, too...could be a combination of things going on here.

Hope this helps. -Al

Hi Al, thanks for all of your advice.

I'm using a cutter that's marked 33 degrees, would 2 degrees make a difference?

Don't believe the load is too light (2980FPS/115G projectiles) and I'm pretty good about the bump(try to stay 1 tho or less). I had a few loaded rounds left and the OD is 2 tho under the chamber (.228 on a .330)

My guess is the shape/Cut of the brass is the culprit?

 

[TommyD11730]

Here is my 2 cents.......

Before you ditch all that brass, use a dremel and section one case lengthwise. You will notice a "ditch" internally and opposite the external area. If that "ditch" is less thick than the surrounding brass thickness of the neck and the shoulder immediately below it, ditch the brass or deal with the imminent neck separations.
If there is no internal "ditch" and brass thickness is the same as the other areas of the NECK, then you probably used too acute of a cutter angle. In this case, the increased shoulder brass thickness (even with the outside "dig) should be sufficient to prevent separations.

Either way, unless you are really jumping bullets, you don't need to turn onto the shoulder that far.

Cutting open a piece of the old brass is a great idea. Ill definitely do that, thanks!

 

[TommyD11730]

You will lose those necks ........... eventually. Take it from one with experience (in losing the neck). My first cutting job was to far down on the neck, I'd eject the case and there was no neck at all OR half the neck left. Not fun or a pretty sight! We try, we experiment and hopefully learn! I learn with every new experience, by the time I'm 100 years old I should have it down .............. or be dead, probably dead. Have a blessed day!!

I agree with you. Im making sure I pack my extractor going fwd (If I shoot that brass!).

 

[muleystalker]

With the c

Hi Al, thanks for all of your advice.

I'm using a cutter that's marked 33 degrees, would 2 degrees make a difference?

Don't believe the load is too light (2980FPS/115G projectiles) and I'm pretty good about the bump(try to stay 1 tho or less). I had a few loaded rounds left and the OD is 2 tho under the chamber.

My guess is the shape/Cut of the brass is the culprit?

You say your good about the bump and I'm sure you are but as rough as those cases are and as high as that ridge is on the shoulder there is no way you could get a consistent shoulder bump on that brass. The ridge/ high spot are not letting the shoulder seat against the chamber, I suspect thats where the carbon blow by is coming from.

 

[TommyD11730]

Ok so I had some time on my hands and I figured.. why not ruin some more brass (kidding I hope!).

So I was gentle on the Lapua brass necking it up. Made 4 short strokes with the PMA expander, rotating between to make sure I didn't harm anything.

Then came the turning. I had already decided I wanted to try and keep the necks thicker than last time, 010" was my goal. So once I had my thickness set I SLOWLY started cutting further back on the brass. After each cut I would clean the case and try to chamber in my chamber. Once I determined that(yes I have to cut slightly into the neck junction to chamber) I added just a kiss more. Comparing the new vs old its pretty obvious how far I cut into the neck last time vs today.

My only concern now is with the slightly thicker brass I still make it to .330. Having .002 clearance before fingers crossed Ill be ok.

Thanks for not running me through the wringer guys!

 

[TommyD11730]

With the c

You say your good about the bump and I'm sure you are but as rough as those cases are and as high as that ridge is on the shoulder there is no way you could get a consistent shoulder bump on that brass. The ridge/ high spot are not letting the shoulder seat against the chamber, I suspect thats where the carbon blow by is coming from.

Thats a EXCELLANT point. Now I have to wonder about my comparator I use to measure bump.

Strangely enough the SD on this brass was excellent (to me) with single digets for 45 rounds fired. HOWEVER the ES was not good @ 38.5 FPS. There were 2 horrible flyers that I took the blame for. When time came to anneal the brass I could see 2 pieces that the necks lit up like a Christmas tree!

 

[Shooter13]

What is the pressure ring on your bullet? I use BIBs 112 and they are .3087 so for .002 clearance I cut my brass to .00965 (maybe LOL) really as close to .0095 as I can and that assures me of .002 clearance. Just for your consideration.

 

[AlNyhus]

I'm using a cutter that's marked 33 degrees, would 2 degrees make a difference?

As long as it's more than the shoulder angle, you're good.

 

[AlNyhus]

Also, the wavy appearance of the blend is due to the necks being off axis with the case body after being necked up. It's not a big deal but it can cause some cutter 'dig' if you're not careful.

After expanding, I use a 'delumper' die with a .327 fixed neck dimension to straighten the neck relative to the body and remove the external 'lump' prior to turning. Doing this makes the blend into the shoulder very uniform. Here's an example....the blend cut was carried intentionally too far down to illustrate this. The sharpie marks on the cases are at 180 degrees from each other. You can also see where the 'lump' was.

For what it's worth....

 

[P1ZombieKiller]

it also looks like your new cuts are little rough.
It appears you need to be slower on the "in/out" process.
Slow in. Slower out is my advice.

 

[TommyD11730]

Also, the wavy appearance of the blend is due to the necks being off axis with the case body after being necked up. It's not a big deal but it can cause some cutter 'dig' if you're not careful.

After expanding, I use a 'delumper' die with a .327 fixed neck dimension to straighten the neck relative to the body and remove the external 'lump' prior to turning. Doing this makes the blend into the shoulder very uniform. Here's an example....the blend cut was carried intentionally too far down to illustrate this. The sharpie marks on the cases are at 180 degrees from each other. You can also see where the 'lump' was.

For what it's worth....

Wow! Here I thought the cut being not exactly concentric was a result of my KN setup.
So you know my next question, where do I find a "delump-er die"?
Great info.. thanks!

 

[P1ZombieKiller]

don't sweat the "un-even-ness". Just don't dig in too deep into the shoulder.
I have found that if you go up in 2 stages ( like from .243 to .284 to .308) it helps to eliminate that a lot. But its really not too big of a deal.

If you use another expander die, it needs to be in conjunction with your turning mandrel. If you expand too much, the brass will fit on your turning mandrel sloppy, and then you have a whole different issue on your hand.

 

[TommyD11730]

don't sweat the "un-even-ness". Just don't dig in too deep into the shoulder.
I have found that if you go up in 2 stages ( like from .243 to .284 to .308) it helps to eliminate that a lot. But its really not too big of a deal.

If you use another expander die, it needs to be in conjunction with your turning mandrel. If you expand too much, the brass will fit on your turning mandrel sloppy, and then you have a whole different issue on your hand.

The PMA mandrel is actually smaller then the mandrel on my K & M turner. So, I use the K & M expander so it will fit on the K & M turning mandrel (I believe I measured it as .3085)
Then I neck size the brass before 1st firing.

 

[TommyD11730]

it also looks like your new cuts are little rough.
It appears you need to be slower on the "in/out" process.
Slow in. Slower out is my advice.

Yes, trying to find a balance as I'm trying to keep the heat down.
Any suggestions on a lube for the mandrel when turning?