How deep is too deep?

[DRNewcomb]

#include [generic_double_entendre]

 

[6MMsteve]

Plan B go to Plan B LOL, My 1st 260 barrel was short freebore but I think I have washed it out

 

[mike a]

Besides the neck walls being thicker at the neck/shoulder junction than at the case mouth, I like to think of the shoulder as a buttress. When the neck expands at the shoulder junction, there's a force vector trying to compress the shoulder walls towards the shoulder/body junction, but naturally there's stiff resistance, so the spring-back at the neck/shoulder junction is more pronounced than elsewhere on the neck.
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+1 to you, Buttress and Force Vectors I may not understand however I've found that in my 30 deg shoulder 6.5 creedmoor brass. With zero neck tension bullet slides right in. With .0001 n/t bullet seats easy until the junction. At first I thought it was a donut but no! It's that buttress thingy. I don't experience this in my 20 deg shoulder 243 or 308. Its like having variable neck tension. I don't like it and haven't yet got a handle on it. .002 n/t and the seater leaves a ring on the bullet. Sorry op don't mean to steal you thread. Thanx mike

 

[mikecr]

Im fl resizing. And what plan are you talking about? This is not the only bullet i plan to try. I also am going to try 130 hybrids. Im not sure why i would get a donut im not neck turning at all.

If you're FL sizing necks(actual FL sizing), AND seating bullet bearing right through neck/shoulder junction, then w/resp to accuracy you have a bad plan.
Not only do you bring donut area into tension, you also bring the neck-shoulder junction(reinforced by the shoulder angle) into tension.
Yes, it will shoot, but the tension gripping your bullets will vary across the widest scale.
You might search & read up on donuts. What they are, there causes, affects, and mitigating them.

 

[jlow]

Not always. Tests have shown as bullets starting out against the lands then incrementally seated deeper in case necks, pressure drops for a ways then starts back up. Somewhere mid point in bullet seating depths is where pressure is lowest. The range peak pressure has varies with bullet extraction (pull) force, throat dimensions and bullet hardness as well as powder burn rates.

Going from jam to jump of course will reduce pressure – that is a given. We are not talking about that, just the effect of reduced case volume.

Of course, as you seat deeper, you are reducing case volume but also the amount of powder you can put in a case unless you are going to accept a compressed load. Reducing your powder to compensate will reduce your MVs.

Every thing you mention could be a factor but again, we are talking about just seating deeper not changing anything else.

 

[Brians356]

how much helium in your mix?

Enough to barely tolerate drive-by comments with no redeeming content and zero value.
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[swadiver]

Enough to barely tolerate drive-by comments with no redeeming content and zero value.
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yo. take your chill pill. it was a joke for the technical divers on the forum.

 

[Brians356]

yo. take your chill pill. it was a joke for the technical divers on the forum.

Ah. Got it. Good one. First it's helium, now chill pills. I begin to know you a little, or well enough anyway.
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