I thought we were talking about depth of penetration. How does the issue of straight line penetration come into play? Why are you asking about straight line penetration rather than depth of penetration?

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Alf,

I am curious why you would ask about straightline penetration rather than just depth of penetration, because they are two different things. But to answer your question, the water would splash and some boards would get holes in them.

Keep in mind that the preference some of us show for flat nosed solids is due to observing the following compared to round nose solids:

1. greater depth of penetration
2. wider wound channels
3. less deviation from straight line penetration

Only Norbert's supercavitation explanation explains the data.

Can you offer any alternative explanation?

quote:

Originally posted by 500grains:

Only Norbert's supercavitation explanation explains the data.

Can you offer any alternative explanation?

500grains,

Bullet deflection can be mechanical as well.

Any area of a bullet that is not parallel to the longitudinal plane of our bullet's travel or perpendicular (as flat nose) works against us.

As to the round nose solid: The angular ogive and radius on the nose induces a "turning", "bending", even "tumbling" effect with mechanical advantage working against us! If stresses are "loaded" more on one side or another the bullet will arc or turn almost like it has a rudder! This leverage can yaw or flip as well with more frontal area produced in the process......(Hence less penetration) I believe the RN "curves" most of the time even when our inaccurate observation doesn't pick it up as we observe the wound channel.

Both the shank and the flat nose help to keep us straight. I think the Keith-type shoulder does as well (as it eliminates more angular area)..... What is hard for me to visualize is this shoulder having any effect during supercavitation in our animal if indeed that is what is taking place........

BigRx

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quote:

Originally posted by ALF:


Optimum velocity issues:

It has been shown that for each caliber / bullet length there appears to be a optimum velocity window where in the projectile increases it's penetration and then at a certain higher velocity penetration starts dropping off :

I believe what likely happens is that inside that ideal velocity window the projectile "self corrects" and stabilizes yaw and as soon as you go over the velocity ceiling it can no longer do so and drag increases due to an increase in angle of attack.... at this point if you increase velocity further you may get to a point where you reach an overturn moment and the bullet may tumble.

That may explain why the 458 Lott used to outpenetrate the 460 Wby (not sure if that is still true). But then why does a faster twist improve penetration? Norbert's explanation of stabilization of the supercavitation bubble is the only viable explanation for that phenomena that I am aware of.

As for supercavitation versus cavitation, I take it that you do not agree that water is liberated from living tissue to form a supercavitation bubble. If that is the point of disagreement, then it seems to be a small one, and can almost be ascribed to terminology.

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