Does bullet nose profile significantly affect penetration consistency?

[Naphtali]

For years I have believed, without proof, that a bullet with a flat nose of approximately 75 percent of bullet diameter will be significantly more likely to penetrate the flesh, bone, sinew, and so on of larger game animals - without changing its direction of penetration - than pointed and round-nose bullet shapes. My bullet testing on dry clay-backed paper and wet shows when bullets change shape during penetration, sometimes that shape change, aka mushrooming, unbalances the bullet which then changes its direction. But this is penetration of paper. I have no idea whether any testing for this facet of bullet penetration has occurred on animals.
***
Interestingly, this research has been done for bow hunting by an American retired optometrist named Ashby. Doctor Ashby retired to Australia where he conducted (is still conducting??) research to identify shape and weight of broadheads that are most effective on extremely large game. "Extremely large game" in this case means Asian buffalo in Australia's Northern Territory. Although testing was oriented for traditional bows, compound users can use his data equally effectively.
***
I have not shot a jacketed bullet in handgun or rifle in decades. While my query and paper testing has occurred only with cast bullets, I cannot identify a reason why if a pattern exists, the pattern will not include jacketed bullets. The only time a non-lead bullet was included in testing was to compare effect on paper of my .72-caliber conical load from my double rifle with a Barnes Triple Shock 150-grain .30-caliber bullet at chronographed 2900 ft/sec, a load that had killed more than ten elk.

[Rcmaveric]

Nose profile does in a way. Cross section density plays more into penetration than nose profile. Nose profile affects more energy transfer aspect, in the way of hydrostatic shock and knock down. You hit flesh something like a spire point its going to be like a pencil going through if the projectile doesn't mushroom with little energy transfer or shock and the elasticity of the flesh and skin will seal the wound. A good meplate insures that their is some transfer and shock if expansion fails or atleast puts a big enough hole that the elasticity of the skin and flesh cant seal the wound and stop bleading. Its hard to equate bullets to arrows because arrows have an amazingly efficient energy transfer. While bullets are inefficient due them passing through and retaining the energy as it keeps trucking down range. That's also why soft heavy bullets going slow are more tramatic. That bigger bullet is like getting hit with a cookie cutter. They leave a devastating wound. An arrow hitting is way more tramatic. There is a slow motion video floating around that explains it.

[Messy bear]

Absolutely! A friend and I used to test large rifles on large dead critters. The most dismall failures were round nose solids. They would exit with a zinging sound and fly off to who knows where. File a flat on the nose and catch them in the bank behind. Always wondered why companies took so long to realize this.

One very memorable experience was with paper and a 45 colt. We set up to test a straight twist barrel and as we were getting ready someone said don't put up much paper. So we layed up about 28 inches IIRC. The 310 Keith went straight through and out the back of the 2x8 backer board! So we set up 38 inches and this time the bullet dented the board and bounced back into channel a few inches. It was nose forward! Penetration was plumb straight!

[fredj338]

Extensive testing has been dome on the field on live game in Africa. A FN solid does tend to penetrate in a straight line & breaks bone where a RN may deflect. Testing on dry paper is just not a good test IMO. Way back when, many gun rags tested RN & flat nose & spritzer bullets on dowel screens, RN always deflect as do spritzers when striking he dowels off center.