30BR neck turning sanity check and questions

[SVT_Tactical]

I wouldn't cut into shoulder unless you needed to. Why remove material if it's not in the way.

 

[JEFFPPC]

I wouldn't cut into shoulder unless you needed to. Why remove material if it's not in the way.

The theory is to help prevent donuts.

 

[DJSBRS]

When you neck it up to 30 caliber, it will have a huge donut on the outside of the neck about 3/4 of the way down the neck. That donut is where the shoulder neck junction was on the 6 BR and now stretched up the neck while expanding to the new 30 caliber. That donut must be cut off and down to the neck shoulder junction for proper clearance and to take in accordance of future brass flow at the neck shoulder junction after numerous firings.

DJ
DJ's Brass Service

 

[FNSafari]

My reamer specs. does not dictate cutting into the shoulders. Never had an issue with chambering Lapua or Peterson brass.

My Henrikson does require a slight cut into the shoulder. I guess that's why they call them wildcats...no standard dimensions.

 

[gunsandgunsmithing]

Is there any data or basis concluding that donuts hurt anything at all as long as the bullet is seated safely above it? I've read theories of venturi effect and all kinds of stuff but have never seen any real world data for or against leaving that area mostly, as is or close to it. Seems logical and you don't run even the possibility of cutting too deep.

 

[Link]

Pay to have them done. I have done quite a few, now i farmem out.

;]

 

[AlNyhus]

A nice blend into the shoulder prevents the dreaded 'WMFNG'* syndrome.

*Where'd My F'ing Neck Go?

 

[6BRA]

A full blade width skim into the shoulder hurts nothing. You don't want it deep but just slightly able to be felt by fingernail hurts nothing in my experience. 0000 steel wool and 2 firings and you will never feel it anymore.

 

[AlNyhus]

This is an exaggerated example of how I do my 30BR cases. The dark ring you see at the bottom of the neck is where the external 'lump' was from the necking up process. Below that is a narrow section that's where the shoulders are intentionally pushed back .020-ish for the first firing. The blend cut into the shoulder is about twice as long as I normally set up for. This is done with a 35 degree cutter and you can see how nicely that feathers out with no 'dig in' like you can get with a 30 degree cutter. As you can see by the uniformity of the shoulder blend, the case necks are not tipped at the neck/shoulder junction. If they are, you'll get a wavy blend cut into the shoulder. There are ways around this afterward. The best approach is to minimize it from the start.

For what it's worth. -Al

 

[6BRA]

This is an exaggerated example of how I do my 30BR cases. The dark ring you see at the bottom of the neck is where the external 'lump' was from the necking up process. Below that is a narrow section that's where the shoulders are intentionally pushed back .020-ish for the first firing. The blend cut into the shoulder is about twice as long as I normally set up for. This is done with a 35 degree cutter and you can see how nicely that feathers out with no 'dig in' like you can get with a 30 degree cutter. As you can see by the uniformity of the shoulder blend, the case necks are not tipped at the neck/shoulder junction. If they are, you'll get a wavy blend cut into the shoulder. There are ways around this afterward. The best approach is to minimize it from the start.

For what it's worth. -Al

I wish they would make a 45 deg cutter for the Ackleys.

 

[AlNyhus]

I wish they would make a 45 deg cutter for the Ackleys.

If you're using their turner, PMA makes a 45 degree cutter. On my 40 degree cases (250 Savage AI and 6mm Jet), I just turn the parent case with a +5 degree cutter for the original shoulder angle prior to f-forming.

 

[6BRA]

If you're using their turner, PMA makes a 45 degree cutter. On my 40 degree cases (250 Savage AI and 6mm Jet), I just turn the parent case with a +5 degree cutter for the original shoulder angle prior to f-forming.

I'll have to look at that 45 deg cutter. I was unaware. I have 2 PMA and a Pumpkin.

 

[LCazador]

Honestly, I've never turned necks by the 'math'. I turn them until they measure what I want over the pressure ring.

I would recommend what AlNyhus say's ^^^! Do a trial run with a few. It's what I call real life measurements!

 

[LCazador]

When you neck it up to 30 caliber, it will have a huge donut on the outside of the neck about 3/4 of the way down the neck. That donut is where the shoulder neck junction was on the 6 BR and now stretched up the neck while expanding to the new 30 caliber. That donut must be cut off and down to the neck shoulder junction for proper clearance and to take in accordance of future brass flow at the neck shoulder junction after numerous firings.

DJ
DJ's Brass Service

This is exactly the way it should be done. Cut just enough to remove the outside donut for proper clearance. I had numerous neck detachments when I tried cutting anymore then that! Don't worry about an inside donut you'll never be seating close to it with the 30BR.