carpassasin
Well-Known Member
Will the pressure increase seating the bullet deeper away from the lands
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question on pressure.
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Depends, sometimes. I hope this helps
carpassasin
Well-Known Member
Thanks i have been reloading for a long time but never messed with high presure loads.Running 196 hammers in a browning abolt 20 thousands off lands way to long for stock mag.
I'm pretty sure increasing bullet jump will not
increase pressure as the bullet is jumping into the freebore and less resistance. On the other hand, i believe it's common knowledge that pressure spikes can occur when bullets are seated too long and jammed into the lands. If the powder charge is at or near max, this can be dangerous. bench rest shooters often jam their bullets but at reduced charge weights.
increase pressure as the bullet is jumping into the freebore and less resistance. On the other hand, i believe it's common knowledge that pressure spikes can occur when bullets are seated too long and jammed into the lands. If the powder charge is at or near max, this can be dangerous. bench rest shooters often jam their bullets but at reduced charge weights.
Doom2
Well-Known Member
For a given load with the bullet seated in the lands the pressure will be at maximum. As the bullet moves away from the lands it will decrease rapidly at first then begin to flatten out. At some point as the bullet is seated deeper it will usually begin to rise again.
carpassasin
Well-Known Member
Thanks for the info always willing to learn.Stock rifle with a hudge jump if seated to fit mag.
According to QL, pressure will jump as coal decreases. My 6.5CM load (43.5 RL16/130 Berger) predicts a pressure of 57,627 psi at 2.97". Decreasing COAL to 2.9" increases pressure to 60,051 ps. In this case, the I suspect the decrease in usable case capacity from 48.7 to 47.7 grains is the likely cause of the pressure increase.
^^^^This.
Doom2
Well-Known Member
Not sure exactly how QL handles the point where the bullet releases but it's different when the bullet is in the lands. It will be the highest pressure because the bullet is fixed and has no kinetic energy so it depends on pressure to engrave. As the bullet jump increases the bullet releases based on neck tension and gains kinetic energy prior to engraving.
Does no one read the 1st couple of chapters of reloading manuals? This is covered in the basics. Jam, or touching, pressure spikes. Jump, pressure drops. If you jam, reduce the powder charge. If you're jumping, increase the powder charge. In my experience, hammers like a bit of jump, also drop down in burn speed to a faster burn powder to get a better case fill and pick up the speed you're looking for. Load until you hit pressure, then drop the charge. Hammers seem to be easy to load for accuracy.
Doom2
Well-Known Member
You have to wonder but books seem to be a lost source of information for the younger generations. The section from the Hornady manual on pressure is actually available online.
Internal Ballistics - Hornady Manufacturing, Inc
Internal Ballistics Video Library...
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